diff --git a/examples/xpub_descriptors.rs b/examples/xpub_descriptors.rs
index c66f26307..54f68ba29 100644
--- a/examples/xpub_descriptors.rs
+++ b/examples/xpub_descriptors.rs
@@ -18,7 +18,7 @@ use std::str::FromStr;
 
 use miniscript::bitcoin::secp256k1::{Secp256k1, Verification};
 use miniscript::bitcoin::{Address, Network};
-use miniscript::{Descriptor, DescriptorPublicKey, TranslatePk2};
+use miniscript::{Descriptor, DescriptorPublicKey};
 
 const XPUB_1: &str = "xpub661MyMwAqRbcFW31YEwpkMuc5THy2PSt5bDMsktWQcFF8syAmRUapSCGu8ED9W6oDMSgv6Zz8idoc4a6mr8BDzTJY47LJhkJ8UB7WEGuduB";
 const XPUB_2: &str = "xpub69H7F5d8KSRgmmdJg2KhpAK8SR3DjMwAdkxj3ZuxV27CprR9LgpeyGmXUbC6wb7ERfvrnKZjXoUmmDznezpbZb7ap6r1D3tgFxHmwMkQTPH";
@@ -42,7 +42,7 @@ fn p2wsh<C: Verification>(secp: &Secp256k1<C>) -> Address {
 
     let address = Descriptor::<DescriptorPublicKey>::from_str(&s)
         .unwrap()
-        .translate_pk2(|xpk| xpk.derive_public_key(secp))
+        .derived_descriptor(&secp, 0) // dummy index value if it not a wildcard
         .unwrap()
         .address(Network::Bitcoin)
         .unwrap();
diff --git a/src/descriptor/bare.rs b/src/descriptor/bare.rs
index be5be5483..0b3159ab6 100644
--- a/src/descriptor/bare.rs
+++ b/src/descriptor/bare.rs
@@ -19,7 +19,6 @@
 //!
 
 use core::fmt;
-use core::str::FromStr;
 
 use bitcoin::blockdata::script;
 use bitcoin::{Address, Network, Script};
@@ -32,7 +31,7 @@ use crate::prelude::*;
 use crate::util::{varint_len, witness_to_scriptsig};
 use crate::{
     BareCtx, Error, ForEach, ForEachKey, Miniscript, MiniscriptKey, Satisfier, ToPublicKey,
-    TranslatePk,
+    TranslatePk, Translator,
 };
 
 /// Create a Bare Descriptor. That is descriptor that is
@@ -145,35 +144,24 @@ impl<Pk: MiniscriptKey> Liftable<Pk> for Bare<Pk> {
     }
 }
 
-impl<Pk> FromTree for Bare<Pk>
-where
-    Pk: MiniscriptKey + FromStr,
-    Pk::Hash: FromStr,
-    <Pk as FromStr>::Err: ToString,
-    <<Pk as MiniscriptKey>::Hash as FromStr>::Err: ToString,
-{
+impl_from_tree!(
+    Bare<Pk>,
     fn from_tree(top: &expression::Tree) -> Result<Self, Error> {
         let sub = Miniscript::<Pk, BareCtx>::from_tree(top)?;
         BareCtx::top_level_checks(&sub)?;
         Bare::new(sub)
     }
-}
-
-impl<Pk> FromStr for Bare<Pk>
-where
-    Pk: MiniscriptKey + FromStr,
-    Pk::Hash: FromStr,
-    <Pk as FromStr>::Err: ToString,
-    <<Pk as MiniscriptKey>::Hash as FromStr>::Err: ToString,
-{
-    type Err = Error;
+);
 
+impl_from_str!(
+    Bare<Pk>,
+    type Err = Error;,
     fn from_str(s: &str) -> Result<Self, Self::Err> {
         let desc_str = verify_checksum(s)?;
         let top = expression::Tree::from_str(desc_str)?;
         Self::from_tree(&top)
     }
-}
+);
 
 impl<Pk: MiniscriptKey> ForEachKey<Pk> for Bare<Pk> {
     fn for_each_key<'a, F: FnMut(ForEach<'a, Pk>) -> bool>(&'a self, pred: F) -> bool
@@ -192,14 +180,11 @@ where
 {
     type Output = Bare<Q>;
 
-    fn translate_pk<Fpk, Fpkh, E>(&self, mut fpk: Fpk, mut fpkh: Fpkh) -> Result<Self::Output, E>
+    fn translate_pk<T, E>(&self, t: &mut T) -> Result<Self::Output, E>
     where
-        Fpk: FnMut(&P) -> Result<Q, E>,
-        Fpkh: FnMut(&P::Hash) -> Result<Q::Hash, E>,
-        Q: MiniscriptKey,
+        T: Translator<P, Q, E>,
     {
-        Ok(Bare::new(self.ms.translate_pk(&mut fpk, &mut fpkh)?)
-            .expect("Translation cannot fail inside Bare"))
+        Ok(Bare::new(self.ms.translate_pk(t)?).expect("Translation cannot fail inside Bare"))
     }
 }
 
@@ -313,13 +298,8 @@ impl<Pk: MiniscriptKey> Liftable<Pk> for Pkh<Pk> {
     }
 }
 
-impl<Pk> FromTree for Pkh<Pk>
-where
-    Pk: MiniscriptKey + FromStr,
-    Pk::Hash: FromStr,
-    <Pk as FromStr>::Err: ToString,
-    <<Pk as MiniscriptKey>::Hash as FromStr>::Err: ToString,
-{
+impl_from_tree!(
+    Pkh<Pk>,
     fn from_tree(top: &expression::Tree) -> Result<Self, Error> {
         if top.name == "pkh" && top.args.len() == 1 {
             Ok(Pkh::new(expression::terminal(&top.args[0], |pk| {
@@ -333,23 +313,17 @@ where
             )))
         }
     }
-}
-
-impl<Pk> FromStr for Pkh<Pk>
-where
-    Pk: MiniscriptKey + FromStr,
-    Pk::Hash: FromStr,
-    <Pk as FromStr>::Err: ToString,
-    <<Pk as MiniscriptKey>::Hash as FromStr>::Err: ToString,
-{
-    type Err = Error;
+);
 
+impl_from_str!(
+    Pkh<Pk>,
+    type Err = Error;,
     fn from_str(s: &str) -> Result<Self, Self::Err> {
         let desc_str = verify_checksum(s)?;
         let top = expression::Tree::from_str(desc_str)?;
         Self::from_tree(&top)
     }
-}
+);
 
 impl<Pk: MiniscriptKey> ForEachKey<Pk> for Pkh<Pk> {
     fn for_each_key<'a, F: FnMut(ForEach<'a, Pk>) -> bool>(&'a self, mut pred: F) -> bool
@@ -368,11 +342,10 @@ where
 {
     type Output = Pkh<Q>;
 
-    fn translate_pk<Fpk, Fpkh, E>(&self, mut fpk: Fpk, _fpkh: Fpkh) -> Result<Self::Output, E>
+    fn translate_pk<T, E>(&self, t: &mut T) -> Result<Self::Output, E>
     where
-        Fpk: FnMut(&P) -> Result<Q, E>,
-        Fpkh: FnMut(&P::Hash) -> Result<Q::Hash, E>,
+        T: Translator<P, Q, E>,
     {
-        Ok(Pkh::new(fpk(&self.pk)?))
+        Ok(Pkh::new(t.pk(&self.pk)?))
     }
 }
diff --git a/src/descriptor/key.rs b/src/descriptor/key.rs
index 657100d6e..edcd43b6d 100644
--- a/src/descriptor/key.rs
+++ b/src/descriptor/key.rs
@@ -4,7 +4,7 @@ use core::str::FromStr;
 use std::error;
 
 use bitcoin::hashes::hex::FromHex;
-use bitcoin::hashes::{hash160, Hash, HashEngine};
+use bitcoin::hashes::{hash160, sha256, Hash, HashEngine};
 use bitcoin::secp256k1::{Secp256k1, Signing, Verification};
 use bitcoin::util::bip32;
 use bitcoin::{self, XOnlyPublicKey, XpubIdentifier};
@@ -737,6 +737,7 @@ impl<K: InnerXKey> DescriptorXKey<K> {
 impl MiniscriptKey for DescriptorPublicKey {
     // This allows us to be able to derive public keys even for PkH s
     type Hash = Self;
+    type Sha256 = bitcoin::hashes::sha256::Hash;
 
     fn is_uncompressed(&self) -> bool {
         match self {
@@ -802,6 +803,7 @@ impl fmt::Display for DerivedDescriptorKey {
 impl MiniscriptKey for DerivedDescriptorKey {
     // This allows us to be able to derive public keys even for PkH s
     type Hash = Self;
+    type Sha256 = bitcoin::hashes::sha256::Hash;
 
     fn is_uncompressed(&self) -> bool {
         self.key.is_uncompressed()
@@ -825,6 +827,10 @@ impl ToPublicKey for DerivedDescriptorKey {
     fn hash_to_hash160(hash: &Self) -> hash160::Hash {
         hash.to_public_key().to_pubkeyhash()
     }
+
+    fn to_sha256(hash: &sha256::Hash) -> sha256::Hash {
+        *hash
+    }
 }
 
 #[cfg(test)]
diff --git a/src/descriptor/mod.rs b/src/descriptor/mod.rs
index 57bc91de2..46d1adfa9 100644
--- a/src/descriptor/mod.rs
+++ b/src/descriptor/mod.rs
@@ -28,6 +28,7 @@ use core::ops::Range;
 use core::str::{self, FromStr};
 
 use bitcoin::blockdata::witness::Witness;
+use bitcoin::hashes::sha256;
 use bitcoin::util::address::WitnessVersion;
 use bitcoin::{self, secp256k1, Address, Network, Script, TxIn};
 use sync::Arc;
@@ -36,8 +37,8 @@ use self::checksum::verify_checksum;
 use crate::miniscript::{Legacy, Miniscript, Segwitv0};
 use crate::prelude::*;
 use crate::{
-    expression, miniscript, BareCtx, Error, ForEach, ForEachKey, MiniscriptKey, Satisfier,
-    ToPublicKey, TranslatePk, TranslatePk2,
+    expression, miniscript, BareCtx, Error, ForEach, ForEachKey, MiniscriptKey, PkTranslator,
+    Satisfier, ToPublicKey, TranslatePk, Translator,
 };
 
 mod bare;
@@ -475,25 +476,19 @@ where
     Q: MiniscriptKey,
 {
     type Output = Descriptor<Q>;
+
     /// Converts a descriptor using abstract keys to one using specific keys.
-    ///
-    /// # Panics
-    ///
-    /// If `fpk` returns an uncompressed key when converting to a Segwit descriptor.
-    /// To prevent this panic, ensure `fpk` returns an error in this case instead.
-    fn translate_pk<Fpk, Fpkh, E>(&self, mut fpk: Fpk, mut fpkh: Fpkh) -> Result<Descriptor<Q>, E>
+    fn translate_pk<T, E>(&self, t: &mut T) -> Result<Self::Output, E>
     where
-        Fpk: FnMut(&P) -> Result<Q, E>,
-        Fpkh: FnMut(&P::Hash) -> Result<Q::Hash, E>,
-        Q: MiniscriptKey,
+        T: Translator<P, Q, E>,
     {
         let desc = match *self {
-            Descriptor::Bare(ref bare) => Descriptor::Bare(bare.translate_pk(&mut fpk, &mut fpkh)?),
-            Descriptor::Pkh(ref pk) => Descriptor::Pkh(pk.translate_pk(&mut fpk, &mut fpkh)?),
-            Descriptor::Wpkh(ref pk) => Descriptor::Wpkh(pk.translate_pk(&mut fpk, &mut fpkh)?),
-            Descriptor::Sh(ref sh) => Descriptor::Sh(sh.translate_pk(&mut fpk, &mut fpkh)?),
-            Descriptor::Wsh(ref wsh) => Descriptor::Wsh(wsh.translate_pk(&mut fpk, &mut fpkh)?),
-            Descriptor::Tr(ref tr) => Descriptor::Tr(tr.translate_pk(&mut fpk, &mut fpkh)?),
+            Descriptor::Bare(ref bare) => Descriptor::Bare(bare.translate_pk(t)?),
+            Descriptor::Pkh(ref pk) => Descriptor::Pkh(pk.translate_pk(t)?),
+            Descriptor::Wpkh(ref pk) => Descriptor::Wpkh(pk.translate_pk(t)?),
+            Descriptor::Sh(ref sh) => Descriptor::Sh(sh.translate_pk(t)?),
+            Descriptor::Wsh(ref wsh) => Descriptor::Wsh(wsh.translate_pk(t)?),
+            Descriptor::Tr(ref tr) => Descriptor::Tr(tr.translate_pk(t)?),
         };
         Ok(desc)
     }
@@ -529,7 +524,19 @@ impl Descriptor<DescriptorPublicKey> {
     /// In most cases, you would want to use [`Self::derived_descriptor`] directly to obtain
     /// a [`Descriptor<bitcoin::PublicKey>`]
     pub fn derive(&self, index: u32) -> Descriptor<DerivedDescriptorKey> {
-        self.translate_pk2_infallible(|pk| pk.clone().derive(index))
+        struct Derivator(u32);
+
+        impl PkTranslator<DescriptorPublicKey, DerivedDescriptorKey, ()> for Derivator {
+            fn pk(&mut self, pk: &DescriptorPublicKey) -> Result<DerivedDescriptorKey, ()> {
+                Ok(pk.clone().derive(self.0))
+            }
+
+            fn pkh(&mut self, pkh: &DescriptorPublicKey) -> Result<DerivedDescriptorKey, ()> {
+                Ok(pkh.clone().derive(self.0))
+            }
+        }
+        self.translate_pk(&mut Derivator(index))
+            .expect("BIP 32 key index substitution cannot fail")
     }
 
     /// Derive a [`Descriptor`] with a concrete [`bitcoin::PublicKey`] at a given index
@@ -561,9 +568,28 @@ impl Descriptor<DescriptorPublicKey> {
         secp: &secp256k1::Secp256k1<C>,
         index: u32,
     ) -> Result<Descriptor<bitcoin::PublicKey>, ConversionError> {
-        let derived = self
-            .derive(index)
-            .translate_pk2(|xpk| xpk.derive_public_key(secp))?;
+        struct Derivator<'a, C: secp256k1::Verification>(&'a secp256k1::Secp256k1<C>);
+
+        impl<'a, C: secp256k1::Verification>
+            PkTranslator<DerivedDescriptorKey, bitcoin::PublicKey, ConversionError>
+            for Derivator<'a, C>
+        {
+            fn pk(
+                &mut self,
+                pk: &DerivedDescriptorKey,
+            ) -> Result<bitcoin::PublicKey, ConversionError> {
+                pk.derive_public_key(&self.0)
+            }
+
+            fn pkh(
+                &mut self,
+                pkh: &DerivedDescriptorKey,
+            ) -> Result<bitcoin::hashes::hash160::Hash, ConversionError> {
+                Ok(pkh.derive_public_key(&self.0)?.to_pubkeyhash())
+            }
+        }
+
+        let derived = self.derive(index).translate_pk(&mut Derivator(secp))?;
         Ok(derived)
     }
 
@@ -575,12 +601,22 @@ impl Descriptor<DescriptorPublicKey> {
         secp: &secp256k1::Secp256k1<C>,
         s: &str,
     ) -> Result<(Descriptor<DescriptorPublicKey>, KeyMap), Error> {
-        let parse_key = |s: &String,
-                         key_map: &mut KeyMap|
-         -> Result<DescriptorPublicKey, DescriptorKeyParseError> {
+        fn parse_key<C: secp256k1::Signing>(
+            s: &String,
+            key_map: &mut KeyMap,
+            secp: &secp256k1::Secp256k1<C>,
+        ) -> Result<DescriptorPublicKey, Error> {
             let (public_key, secret_key) = match DescriptorSecretKey::from_str(s) {
-                Ok(sk) => (sk.to_public(secp)?, Some(sk)),
-                Err(_) => (DescriptorPublicKey::from_str(s)?, None),
+                Ok(sk) => (
+                    sk.to_public(secp)
+                        .map_err(|e| Error::Unexpected(e.to_string()))?,
+                    Some(sk),
+                ),
+                Err(_) => (
+                    DescriptorPublicKey::from_str(s)
+                        .map_err(|e| Error::Unexpected(e.to_string()))?,
+                    None,
+                ),
             };
 
             if let Some(secret_key) = secret_key {
@@ -588,26 +624,56 @@ impl Descriptor<DescriptorPublicKey> {
             }
 
             Ok(public_key)
-        };
+        }
+
+        let mut keymap_pk = KeyMapWrapper(HashMap::new(), secp);
+
+        struct KeyMapWrapper<'a, C: secp256k1::Signing>(KeyMap, &'a secp256k1::Secp256k1<C>);
+
+        impl<'a, C: secp256k1::Signing> Translator<String, DescriptorPublicKey, Error>
+            for KeyMapWrapper<'a, C>
+        {
+            fn pk(&mut self, pk: &String) -> Result<DescriptorPublicKey, Error> {
+                parse_key(pk, &mut self.0, self.1)
+            }
+
+            fn pkh(&mut self, pkh: &String) -> Result<DescriptorPublicKey, Error> {
+                parse_key(pkh, &mut self.0, self.1)
+            }
 
-        let mut keymap_pk = KeyMap::new();
-        let mut keymap_pkh = KeyMap::new();
+            fn sha256(&mut self, sha256: &String) -> Result<sha256::Hash, Error> {
+                let hash =
+                    sha256::Hash::from_str(sha256).map_err(|e| Error::Unexpected(e.to_string()))?;
+                Ok(hash)
+            }
+        }
 
         let descriptor = Descriptor::<String>::from_str(s)?;
         let descriptor = descriptor
-            .translate_pk(
-                |pk| parse_key(pk, &mut keymap_pk),
-                |pkh| parse_key(pkh, &mut keymap_pkh),
-            )
+            .translate_pk(&mut keymap_pk)
             .map_err(|e| Error::Unexpected(e.to_string()))?;
 
-        keymap_pk.extend(keymap_pkh.into_iter());
-
-        Ok((descriptor, keymap_pk))
+        Ok((descriptor, keymap_pk.0))
     }
 
     /// Serialize a descriptor to string with its secret keys
     pub fn to_string_with_secret(&self, key_map: &KeyMap) -> String {
+        struct KeyMapLookUp<'a>(&'a KeyMap);
+
+        impl<'a> Translator<DescriptorPublicKey, String, ()> for KeyMapLookUp<'a> {
+            fn pk(&mut self, pk: &DescriptorPublicKey) -> Result<String, ()> {
+                key_to_string(pk, self.0)
+            }
+
+            fn pkh(&mut self, pkh: &DescriptorPublicKey) -> Result<String, ()> {
+                key_to_string(pkh, self.0)
+            }
+
+            fn sha256(&mut self, sha256: &sha256::Hash) -> Result<String, ()> {
+                Ok(sha256.to_string())
+            }
+        }
+
         fn key_to_string(pk: &DescriptorPublicKey, key_map: &KeyMap) -> Result<String, ()> {
             Ok(match key_map.get(pk) {
                 Some(secret) => secret.to_string(),
@@ -616,10 +682,7 @@ impl Descriptor<DescriptorPublicKey> {
         }
 
         let descriptor = self
-            .translate_pk::<_, _, ()>(
-                |pk| key_to_string(pk, key_map),
-                |pkh| key_to_string(pkh, key_map),
-            )
+            .translate_pk(&mut KeyMapLookUp(key_map))
             .expect("Translation to string cannot fail");
 
         descriptor.to_string()
@@ -651,14 +714,9 @@ impl Descriptor<DescriptorPublicKey> {
     }
 }
 
-impl<Pk> expression::FromTree for Descriptor<Pk>
-where
-    Pk: MiniscriptKey + str::FromStr,
-    Pk::Hash: str::FromStr,
-    <Pk as FromStr>::Err: ToString,
-    <<Pk as MiniscriptKey>::Hash as FromStr>::Err: ToString,
-{
-    /// Parse an expression tree into a descriptor
+impl_from_tree!(
+    Descriptor<Pk>,
+    /// Parse an expression tree into a descriptor.
     fn from_tree(top: &expression::Tree) -> Result<Descriptor<Pk>, Error> {
         Ok(match (top.name, top.args.len() as u32) {
             ("pkh", 1) => Descriptor::Pkh(Pkh::from_tree(top)?),
@@ -669,17 +727,11 @@ where
             _ => Descriptor::Bare(Bare::from_tree(top)?),
         })
     }
-}
-
-impl<Pk> FromStr for Descriptor<Pk>
-where
-    Pk: MiniscriptKey + str::FromStr,
-    Pk::Hash: str::FromStr,
-    <Pk as FromStr>::Err: ToString,
-    <<Pk as MiniscriptKey>::Hash as FromStr>::Err: ToString,
-{
-    type Err = Error;
+);
 
+impl_from_str!(
+    Descriptor<Pk>,
+    type Err = Error;,
     fn from_str(s: &str) -> Result<Descriptor<Pk>, Error> {
         // tr tree parsing has special code
         // Tr::from_str will check the checksum
@@ -692,7 +744,7 @@ where
             expression::FromTree::from_tree(&top)
         }
     }
-}
+);
 
 impl<Pk: MiniscriptKey> fmt::Debug for Descriptor<Pk> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
@@ -742,7 +794,7 @@ mod tests {
     use crate::descriptor::{DescriptorPublicKey, DescriptorSecretKey, DescriptorXKey, SinglePub};
     #[cfg(feature = "compiler")]
     use crate::policy;
-    use crate::{hex_script, Descriptor, DummyKey, Error, Miniscript, Satisfier, TranslatePk2};
+    use crate::{hex_script, Descriptor, DummyKey, Error, Miniscript, Satisfier};
 
     type StdDescriptor = Descriptor<PublicKey>;
     const TEST_PK: &'static str =
@@ -1479,19 +1531,14 @@ mod tests {
             assert_eq!(desc_one.to_string(), raw_desc_one);
             assert_eq!(desc_two.to_string(), raw_desc_two);
 
-            // Derive a child in case the descriptor is ranged. If it's not this won't have any
-            // effect
-            let desc_one = desc_one.derive(index);
-            let desc_two = desc_two.derive(index);
-
             // Same address
             let addr_one = desc_one
-                .translate_pk2(|xpk| xpk.derive_public_key(&secp_ctx))
+                .derived_descriptor(&secp_ctx, index)
                 .unwrap()
                 .address(bitcoin::Network::Bitcoin)
                 .unwrap();
             let addr_two = desc_two
-                .translate_pk2(|xpk| xpk.derive_public_key(&secp_ctx))
+                .derived_descriptor(&secp_ctx, index)
                 .unwrap()
                 .address(bitcoin::Network::Bitcoin)
                 .unwrap();
diff --git a/src/descriptor/segwitv0.rs b/src/descriptor/segwitv0.rs
index 8ec2e2348..070d23934 100644
--- a/src/descriptor/segwitv0.rs
+++ b/src/descriptor/segwitv0.rs
@@ -17,7 +17,6 @@
 //! of wsh, wpkh and sortedmulti inside wsh.
 
 use core::fmt;
-use core::str::FromStr;
 
 use bitcoin::{self, Address, Network, Script};
 
@@ -30,7 +29,7 @@ use crate::prelude::*;
 use crate::util::varint_len;
 use crate::{
     Error, ForEach, ForEachKey, Miniscript, MiniscriptKey, Satisfier, Segwitv0, ToPublicKey,
-    TranslatePk,
+    TranslatePk, Translator,
 };
 /// A Segwitv0 wsh descriptor
 #[derive(Clone, Ord, PartialOrd, Eq, PartialEq, Hash)]
@@ -194,13 +193,8 @@ impl<Pk: MiniscriptKey> Liftable<Pk> for Wsh<Pk> {
     }
 }
 
-impl<Pk> FromTree for Wsh<Pk>
-where
-    Pk: MiniscriptKey + FromStr,
-    Pk::Hash: FromStr,
-    <Pk as FromStr>::Err: ToString,
-    <<Pk as MiniscriptKey>::Hash as FromStr>::Err: ToString,
-{
+impl_from_tree!(
+    Wsh<Pk>,
     fn from_tree(top: &expression::Tree) -> Result<Self, Error> {
         if top.name == "wsh" && top.args.len() == 1 {
             let top = &top.args[0];
@@ -222,7 +216,8 @@ where
             )))
         }
     }
-}
+);
+
 impl<Pk: MiniscriptKey> fmt::Debug for Wsh<Pk> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         match self.inner {
@@ -240,21 +235,15 @@ impl<Pk: MiniscriptKey> fmt::Display for Wsh<Pk> {
     }
 }
 
-impl<Pk> FromStr for Wsh<Pk>
-where
-    Pk: MiniscriptKey + FromStr,
-    Pk::Hash: FromStr,
-    <Pk as FromStr>::Err: ToString,
-    <<Pk as MiniscriptKey>::Hash as FromStr>::Err: ToString,
-{
-    type Err = Error;
-
+impl_from_str!(
+    Wsh<Pk>,
+    type Err = Error;,
     fn from_str(s: &str) -> Result<Self, Self::Err> {
         let desc_str = verify_checksum(s)?;
         let top = expression::Tree::from_str(desc_str)?;
         Wsh::<Pk>::from_tree(&top)
     }
-}
+);
 
 impl<Pk: MiniscriptKey> ForEachKey<Pk> for Wsh<Pk> {
     fn for_each_key<'a, F: FnMut(ForEach<'a, Pk>) -> bool>(&'a self, pred: F) -> bool
@@ -276,14 +265,13 @@ where
 {
     type Output = Wsh<Q>;
 
-    fn translate_pk<Fpk, Fpkh, E>(&self, mut fpk: Fpk, mut fpkh: Fpkh) -> Result<Self::Output, E>
+    fn translate_pk<T, E>(&self, t: &mut T) -> Result<Self::Output, E>
     where
-        Fpk: FnMut(&P) -> Result<Q, E>,
-        Fpkh: FnMut(&P::Hash) -> Result<Q::Hash, E>,
+        T: Translator<P, Q, E>,
     {
         let inner = match self.inner {
-            WshInner::SortedMulti(ref smv) => WshInner::SortedMulti(smv.translate_pk(&mut fpk)?),
-            WshInner::Ms(ref ms) => WshInner::Ms(ms.translate_pk(&mut fpk, &mut fpkh)?),
+            WshInner::SortedMulti(ref smv) => WshInner::SortedMulti(smv.translate_pk(t)?),
+            WshInner::Ms(ref ms) => WshInner::Ms(ms.translate_pk(t)?),
         };
         Ok(Wsh { inner })
     }
@@ -423,13 +411,8 @@ impl<Pk: MiniscriptKey> Liftable<Pk> for Wpkh<Pk> {
     }
 }
 
-impl<Pk> FromTree for Wpkh<Pk>
-where
-    Pk: MiniscriptKey + FromStr,
-    Pk::Hash: FromStr,
-    <Pk as FromStr>::Err: ToString,
-    <<Pk as MiniscriptKey>::Hash as FromStr>::Err: ToString,
-{
+impl_from_tree!(
+    Wpkh<Pk>,
     fn from_tree(top: &expression::Tree) -> Result<Self, Error> {
         if top.name == "wpkh" && top.args.len() == 1 {
             Ok(Wpkh::new(expression::terminal(&top.args[0], |pk| {
@@ -443,23 +426,17 @@ where
             )))
         }
     }
-}
-
-impl<Pk> FromStr for Wpkh<Pk>
-where
-    Pk: MiniscriptKey + FromStr,
-    Pk::Hash: FromStr,
-    <Pk as FromStr>::Err: ToString,
-    <<Pk as MiniscriptKey>::Hash as FromStr>::Err: ToString,
-{
-    type Err = Error;
+);
 
+impl_from_str!(
+    Wpkh<Pk>,
+    type Err = Error;,
     fn from_str(s: &str) -> Result<Self, Self::Err> {
         let desc_str = verify_checksum(s)?;
         let top = expression::Tree::from_str(desc_str)?;
         Self::from_tree(&top)
     }
-}
+);
 
 impl<Pk: MiniscriptKey> ForEachKey<Pk> for Wpkh<Pk> {
     fn for_each_key<'a, F: FnMut(ForEach<'a, Pk>) -> bool>(&'a self, mut pred: F) -> bool
@@ -478,11 +455,10 @@ where
 {
     type Output = Wpkh<Q>;
 
-    fn translate_pk<Fpk, Fpkh, E>(&self, mut fpk: Fpk, _fpkh: Fpkh) -> Result<Self::Output, E>
+    fn translate_pk<T, E>(&self, t: &mut T) -> Result<Self::Output, E>
     where
-        Fpk: FnMut(&P) -> Result<Q, E>,
-        Fpkh: FnMut(&P::Hash) -> Result<Q::Hash, E>,
+        T: Translator<P, Q, E>,
     {
-        Ok(Wpkh::new(fpk(&self.pk)?).expect("Uncompressed keys in Wpkh"))
+        Ok(Wpkh::new(t.pk(&self.pk)?).expect("Uncompressed keys in Wpkh"))
     }
 }
diff --git a/src/descriptor/sh.rs b/src/descriptor/sh.rs
index 332328bea..d9202e67e 100644
--- a/src/descriptor/sh.rs
+++ b/src/descriptor/sh.rs
@@ -19,7 +19,6 @@
 //!
 
 use core::fmt;
-use core::str::FromStr;
 
 use bitcoin::blockdata::script;
 use bitcoin::{Address, Network, Script};
@@ -33,7 +32,7 @@ use crate::prelude::*;
 use crate::util::{varint_len, witness_to_scriptsig};
 use crate::{
     push_opcode_size, Error, ForEach, ForEachKey, Legacy, Miniscript, MiniscriptKey, Satisfier,
-    Segwitv0, ToPublicKey, TranslatePk,
+    Segwitv0, ToPublicKey, TranslatePk, Translator,
 };
 
 /// A Legacy p2sh Descriptor
@@ -91,13 +90,8 @@ impl<Pk: MiniscriptKey> fmt::Display for Sh<Pk> {
     }
 }
 
-impl<Pk> FromTree for Sh<Pk>
-where
-    Pk: MiniscriptKey + FromStr,
-    Pk::Hash: FromStr,
-    <Pk as FromStr>::Err: ToString,
-    <<Pk as MiniscriptKey>::Hash as FromStr>::Err: ToString,
-{
+impl_from_tree!(
+    Sh<Pk>,
     fn from_tree(top: &expression::Tree) -> Result<Self, Error> {
         if top.name == "sh" && top.args.len() == 1 {
             let top = &top.args[0];
@@ -120,22 +114,17 @@ where
             )))
         }
     }
-}
+);
 
-impl<Pk> FromStr for Sh<Pk>
-where
-    Pk: MiniscriptKey + FromStr,
-    Pk::Hash: FromStr,
-    <Pk as FromStr>::Err: ToString,
-    <<Pk as MiniscriptKey>::Hash as FromStr>::Err: ToString,
-{
-    type Err = Error;
+impl_from_str!(
+    Sh<Pk>,
+    type Err = Error;,
     fn from_str(s: &str) -> Result<Self, Self::Err> {
         let desc_str = verify_checksum(s)?;
         let top = expression::Tree::from_str(desc_str)?;
         Self::from_tree(&top)
     }
-}
+);
 
 impl<Pk: MiniscriptKey> Sh<Pk> {
     /// Get the Inner
@@ -409,16 +398,15 @@ where
 {
     type Output = Sh<Q>;
 
-    fn translate_pk<Fpk, Fpkh, E>(&self, mut fpk: Fpk, mut fpkh: Fpkh) -> Result<Self::Output, E>
+    fn translate_pk<T, E>(&self, t: &mut T) -> Result<Self::Output, E>
     where
-        Fpk: FnMut(&P) -> Result<Q, E>,
-        Fpkh: FnMut(&P::Hash) -> Result<Q::Hash, E>,
+        T: Translator<P, Q, E>,
     {
         let inner = match self.inner {
-            ShInner::Wsh(ref wsh) => ShInner::Wsh(wsh.translate_pk(&mut fpk, &mut fpkh)?),
-            ShInner::Wpkh(ref wpkh) => ShInner::Wpkh(wpkh.translate_pk(&mut fpk, &mut fpkh)?),
-            ShInner::SortedMulti(ref smv) => ShInner::SortedMulti(smv.translate_pk(&mut fpk)?),
-            ShInner::Ms(ref ms) => ShInner::Ms(ms.translate_pk(&mut fpk, &mut fpkh)?),
+            ShInner::Wsh(ref wsh) => ShInner::Wsh(wsh.translate_pk(t)?),
+            ShInner::Wpkh(ref wpkh) => ShInner::Wpkh(wpkh.translate_pk(t)?),
+            ShInner::SortedMulti(ref smv) => ShInner::SortedMulti(smv.translate_pk(t)?),
+            ShInner::Ms(ref ms) => ShInner::Ms(ms.translate_pk(t)?),
         };
         Ok(Sh { inner })
     }
diff --git a/src/descriptor/sortedmulti.rs b/src/descriptor/sortedmulti.rs
index e0a6c0910..d3c21a239 100644
--- a/src/descriptor/sortedmulti.rs
+++ b/src/descriptor/sortedmulti.rs
@@ -28,7 +28,7 @@ use crate::miniscript::limits::MAX_PUBKEYS_PER_MULTISIG;
 use crate::prelude::*;
 use crate::{
     errstr, expression, miniscript, policy, script_num_size, Error, ForEach, ForEachKey,
-    Miniscript, MiniscriptKey, Satisfier, ToPublicKey,
+    Miniscript, MiniscriptKey, Satisfier, ToPublicKey, Translator,
 };
 
 /// Contents of a "sortedmulti" descriptor
@@ -94,15 +94,15 @@ impl<Pk: MiniscriptKey, Ctx: ScriptContext> SortedMultiVec<Pk, Ctx> {
     /// This will panic if fpk returns an uncompressed key when
     /// converting to a Segwit descriptor. To prevent this panic, ensure
     /// fpk returns an error in this case instead.
-    pub fn translate_pk<FPk, Q, FuncError>(
+    pub fn translate_pk<T, Q, FuncError>(
         &self,
-        fpk: &mut FPk,
+        t: &mut T,
     ) -> Result<SortedMultiVec<Q, Ctx>, FuncError>
     where
-        FPk: FnMut(&Pk) -> Result<Q, FuncError>,
+        T: Translator<Pk, Q, FuncError>,
         Q: MiniscriptKey,
     {
-        let pks: Result<Vec<Q>, _> = self.pks.iter().map(&mut *fpk).collect();
+        let pks: Result<Vec<Q>, _> = self.pks.iter().map(|pk| t.pk(pk)).collect();
         Ok(SortedMultiVec {
             k: self.k,
             pks: pks?,
diff --git a/src/descriptor/tr.rs b/src/descriptor/tr.rs
index f0b40db5c..7fde28171 100644
--- a/src/descriptor/tr.rs
+++ b/src/descriptor/tr.rs
@@ -20,6 +20,7 @@ use crate::prelude::*;
 use crate::util::{varint_len, witness_size};
 use crate::{
     errstr, Error, ForEach, ForEachKey, MiniscriptKey, Satisfier, Tap, ToPublicKey, TranslatePk,
+    Translator,
 };
 
 /// A Taproot Tree representation.
@@ -127,22 +128,17 @@ impl<Pk: MiniscriptKey> TapTree<Pk> {
     }
 
     // Helper function to translate keys
-    fn translate_helper<FPk, FPkh, Q, Error>(
-        &self,
-        fpk: &mut FPk,
-        fpkh: &mut FPkh,
-    ) -> Result<TapTree<Q>, Error>
+    fn translate_helper<T, Q, Error>(&self, t: &mut T) -> Result<TapTree<Q>, Error>
     where
-        FPk: FnMut(&Pk) -> Result<Q, Error>,
-        FPkh: FnMut(&Pk::Hash) -> Result<Q::Hash, Error>,
+        T: Translator<Pk, Q, Error>,
         Q: MiniscriptKey,
     {
         let frag = match self {
             TapTree::Tree(l, r) => TapTree::Tree(
-                Arc::new(l.translate_helper(fpk, fpkh)?),
-                Arc::new(r.translate_helper(fpk, fpkh)?),
+                Arc::new(l.translate_helper(t)?),
+                Arc::new(r.translate_helper(t)?),
             ),
-            TapTree::Leaf(ms) => TapTree::Leaf(Arc::new(ms.translate_pk(fpk, fpkh)?)),
+            TapTree::Leaf(ms) => TapTree::Leaf(Arc::new(ms.translate_pk(t)?)),
         };
         Ok(frag)
     }
@@ -388,41 +384,32 @@ where
     }
 }
 
-impl<Pk: MiniscriptKey> FromTree for Tr<Pk>
-where
-    Pk: MiniscriptKey + FromStr,
-    Pk::Hash: FromStr,
-    <Pk as FromStr>::Err: ToString,
-    <<Pk as MiniscriptKey>::Hash as FromStr>::Err: ToString,
-{
-    fn from_tree(top: &expression::Tree) -> Result<Self, Error> {
-        // Helper function to parse taproot script path
-        fn parse_tr_script_spend<Pk: MiniscriptKey>(
-            tree: &expression::Tree,
-        ) -> Result<TapTree<Pk>, Error>
-        where
-            Pk: MiniscriptKey + FromStr,
-            Pk::Hash: FromStr,
-            <Pk as FromStr>::Err: ToString,
-            <<Pk as MiniscriptKey>::Hash as FromStr>::Err: ToString,
-        {
-            match tree {
-                expression::Tree { name, args } if !name.is_empty() && args.is_empty() => {
-                    let script = Miniscript::<Pk, Tap>::from_str(name)?;
-                    Ok(TapTree::Leaf(Arc::new(script)))
-                }
-                expression::Tree { name, args } if name.is_empty() && args.len() == 2 => {
-                    let left = parse_tr_script_spend(&args[0])?;
-                    let right = parse_tr_script_spend(&args[1])?;
-                    Ok(TapTree::Tree(Arc::new(left), Arc::new(right)))
-                }
-                _ => Err(Error::Unexpected(
-                    "unknown format for script spending paths while parsing taproot descriptor"
-                        .to_string(),
-                )),
+#[rustfmt::skip]
+impl_block_str!(
+    Tr<Pk>,
+    // Helper function to parse taproot script path
+    fn parse_tr_script_spend(tree: &expression::Tree,) -> Result<TapTree<Pk>, Error> {
+        match tree {
+            expression::Tree { name, args } if !name.is_empty() && args.is_empty() => {
+                let script = Miniscript::<Pk, Tap>::from_str(name)?;
+                Ok(TapTree::Leaf(Arc::new(script)))
+            }
+            expression::Tree { name, args } if name.is_empty() && args.len() == 2 => {
+                let left = Self::parse_tr_script_spend(&args[0])?;
+                let right = Self::parse_tr_script_spend(&args[1])?;
+                Ok(TapTree::Tree(Arc::new(left), Arc::new(right)))
             }
+            _ => Err(Error::Unexpected(
+                "unknown format for script spending paths while parsing taproot descriptor"
+                    .to_string(),
+            )),
         }
+    }
+);
 
+impl_from_tree!(
+    Tr<Pk>,
+    fn from_tree(top: &expression::Tree) -> Result<Self, Error> {
         if top.name == "tr" {
             match top.args.len() {
                 1 => {
@@ -448,7 +435,7 @@ where
                         )));
                     }
                     let tree = &top.args[1];
-                    let ret = parse_tr_script_spend(tree)?;
+                    let ret = Self::parse_tr_script_spend(tree)?;
                     Ok(Tr {
                         internal_key: expression::terminal(key, Pk::from_str)?,
                         tree: Some(ret),
@@ -471,23 +458,17 @@ where
             )));
         }
     }
-}
-
-impl<Pk: MiniscriptKey> FromStr for Tr<Pk>
-where
-    Pk: MiniscriptKey + FromStr,
-    Pk::Hash: FromStr,
-    <Pk as FromStr>::Err: ToString,
-    <<Pk as MiniscriptKey>::Hash as FromStr>::Err: ToString,
-{
-    type Err = Error;
+);
 
+impl_from_str!(
+    Tr<Pk>,
+    type Err = Error;,
     fn from_str(s: &str) -> Result<Self, Self::Err> {
         let desc_str = verify_checksum(s)?;
         let top = parse_tr_tree(desc_str)?;
         Self::from_tree(&top)
     }
-}
+);
 
 impl<Pk: MiniscriptKey> fmt::Debug for Tr<Pk> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
@@ -625,15 +606,14 @@ where
 {
     type Output = Tr<Q>;
 
-    fn translate_pk<Fpk, Fpkh, E>(&self, mut fpk: Fpk, mut fpkh: Fpkh) -> Result<Self::Output, E>
+    fn translate_pk<T, E>(&self, translate: &mut T) -> Result<Self::Output, E>
     where
-        Fpk: FnMut(&P) -> Result<Q, E>,
-        Fpkh: FnMut(&P::Hash) -> Result<Q::Hash, E>,
+        T: Translator<P, Q, E>,
     {
         let translate_desc = Tr {
-            internal_key: fpk(&self.internal_key)?,
+            internal_key: translate.pk(&self.internal_key)?,
             tree: match &self.tree {
-                Some(tree) => Some(tree.translate_helper(&mut fpk, &mut fpkh)?),
+                Some(tree) => Some(tree.translate_helper(translate)?),
                 None => None,
             },
             spend_info: Mutex::new(None),
diff --git a/src/expression.rs b/src/expression.rs
index bcecf2fe8..2c120ffb4 100644
--- a/src/expression.rs
+++ b/src/expression.rs
@@ -27,6 +27,11 @@ pub struct Tree<'a> {
     /// The comma-separated contents of the `(...)`, if any
     pub args: Vec<Tree<'a>>,
 }
+// or_b(pk(A),pk(B))
+//
+// A = musig(musig(B,C),D,E)
+// or_b()
+// pk(A), pk(B)
 
 /// A trait for extracting a structure from a Tree representation in token form
 pub trait FromTree: Sized {
@@ -259,7 +264,4 @@ mod tests {
         assert!(parse_num("+6").is_err());
         assert!(parse_num("-6").is_err());
     }
-
-    // Add tests for tapscript parsing
-    // tr(D,{or_i(pk(A),pk(B)),{after(9),pk(C)}})
 }
diff --git a/src/interpreter/error.rs b/src/interpreter/error.rs
index 075b103aa..65fe2b848 100644
--- a/src/interpreter/error.rs
+++ b/src/interpreter/error.rs
@@ -145,22 +145,18 @@ impl fmt::Display for Error {
             }
             Error::IncorrectWScriptHash => f.write_str("witness script did not match scriptpubkey"),
             Error::InsufficientSignaturesMultiSig => f.write_str("Insufficient signatures for CMS"),
-            Error::InvalidSchnorrSighashType(ref sig) => {
-                write!(
-                    f,
-                    "Invalid sighash type for schnorr signature '{}'",
-                    sig.to_hex()
-                )
-            }
+            Error::InvalidSchnorrSighashType(ref sig) => write!(
+                f,
+                "Invalid sighash type for schnorr signature '{}'",
+                sig.to_hex()
+            ),
             Error::InvalidEcdsaSignature(pk) => write!(f, "bad ecdsa signature with pk {}", pk),
             Error::InvalidSchnorrSignature(pk) => write!(f, "bad schnorr signature with pk {}", pk),
-            Error::NonStandardSighash(ref sig) => {
-                write!(
-                    f,
-                    "Non standard sighash type for signature '{}'",
-                    sig.to_hex()
-                )
-            }
+            Error::NonStandardSighash(ref sig) => write!(
+                f,
+                "Non standard sighash type for signature '{}'",
+                sig.to_hex()
+            ),
             Error::NonEmptyWitness => f.write_str("legacy spend had nonempty witness"),
             Error::NonEmptyScriptSig => f.write_str("segwit spend had nonempty scriptsig"),
             Error::Miniscript(ref e) => write!(f, "parse error: {}", e),
diff --git a/src/interpreter/inner.rs b/src/interpreter/inner.rs
index e335107ec..efe6a44aa 100644
--- a/src/interpreter/inner.rs
+++ b/src/interpreter/inner.rs
@@ -20,7 +20,7 @@ use bitcoin::util::taproot::{ControlBlock, TAPROOT_ANNEX_PREFIX};
 use super::{stack, BitcoinKey, Error, Stack, TypedHash160};
 use crate::miniscript::context::{NoChecks, ScriptContext};
 use crate::prelude::*;
-use crate::{BareCtx, Legacy, Miniscript, MiniscriptKey, Segwitv0, Tap};
+use crate::{BareCtx, Legacy, Miniscript, MiniscriptKey, PkTranslator, Segwitv0, Tap};
 
 /// Attempts to parse a slice as a Bitcoin public key, checking compressedness
 /// if asked to, but otherwise dropping it
@@ -375,23 +375,39 @@ pub(super) trait ToNoChecks {
 
 impl<Ctx: ScriptContext> ToNoChecks for Miniscript<bitcoin::PublicKey, Ctx> {
     fn to_no_checks_ms(&self) -> Miniscript<BitcoinKey, NoChecks> {
-        // specify the () error type as this cannot error
-        self.real_translate_pk::<_, _, _, (), _>(
-            &mut |pk| Ok(BitcoinKey::Fullkey(*pk)),
-            &mut |pkh| Ok(TypedHash160::FullKey(*pkh)),
-        )
-        .expect("Translation should succeed")
+        struct TranslateFullPk;
+
+        impl PkTranslator<bitcoin::PublicKey, BitcoinKey, ()> for TranslateFullPk {
+            fn pk(&mut self, pk: &bitcoin::PublicKey) -> Result<BitcoinKey, ()> {
+                Ok(BitcoinKey::Fullkey(*pk))
+            }
+
+            fn pkh(&mut self, pkh: &hash160::Hash) -> Result<TypedHash160, ()> {
+                Ok(TypedHash160::FullKey(*pkh))
+            }
+        }
+
+        self.real_translate_pk(&mut TranslateFullPk)
+            .expect("Translation should succeed")
     }
 }
 
 impl<Ctx: ScriptContext> ToNoChecks for Miniscript<bitcoin::XOnlyPublicKey, Ctx> {
     fn to_no_checks_ms(&self) -> Miniscript<BitcoinKey, NoChecks> {
         // specify the () error type as this cannot error
-        self.real_translate_pk::<_, _, _, (), _>(
-            &mut |xpk| Ok(BitcoinKey::XOnlyPublicKey(*xpk)),
-            &mut |pkh| Ok(TypedHash160::XonlyKey(*pkh)),
-        )
-        .expect("Translation should succeed")
+        struct TranslateXOnlyPk;
+
+        impl PkTranslator<bitcoin::XOnlyPublicKey, BitcoinKey, ()> for TranslateXOnlyPk {
+            fn pk(&mut self, pk: &bitcoin::XOnlyPublicKey) -> Result<BitcoinKey, ()> {
+                Ok(BitcoinKey::XOnlyPublicKey(*pk))
+            }
+
+            fn pkh(&mut self, pkh: &hash160::Hash) -> Result<TypedHash160, ()> {
+                Ok(TypedHash160::XonlyKey(*pkh))
+            }
+        }
+        self.real_translate_pk(&mut TranslateXOnlyPk)
+            .expect("Translation should succeed")
     }
 }
 
diff --git a/src/interpreter/mod.rs b/src/interpreter/mod.rs
index 0c96da5fe..0e7af994f 100644
--- a/src/interpreter/mod.rs
+++ b/src/interpreter/mod.rs
@@ -149,6 +149,7 @@ impl TypedHash160 {
 
 impl MiniscriptKey for BitcoinKey {
     type Hash = TypedHash160;
+    type Sha256 = bitcoin::hashes::sha256::Hash;
 
     fn to_pubkeyhash(&self) -> Self::Hash {
         match self {
diff --git a/src/lib.rs b/src/lib.rs
index 9354c8f48..5bac1c908 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -118,6 +118,8 @@ pub mod policy;
 pub mod psbt;
 pub mod timelock;
 
+#[cfg(test)]
+mod test_utils;
 mod util;
 
 use core::str::FromStr;
@@ -153,12 +155,17 @@ pub trait MiniscriptKey: Clone + Eq + Ord + fmt::Debug + fmt::Display + hash::Ha
     /// The associated [`Hash`] type for this pubkey.
     type Hash: Clone + Eq + Ord + fmt::Display + fmt::Debug + hash::Hash;
 
+    /// The associated [`sha256::Hash`] type for this [`MiniscriptKey`] type.
+    /// Used in the sha256 fragment
+    type Sha256: Clone + Eq + Ord + fmt::Display + fmt::Debug + hash::Hash;
+
     /// Converts this key to the associated pubkey hash.
     fn to_pubkeyhash(&self) -> Self::Hash;
 }
 
 impl MiniscriptKey for bitcoin::secp256k1::PublicKey {
     type Hash = hash160::Hash;
+    type Sha256 = sha256::Hash;
 
     fn to_pubkeyhash(&self) -> Self::Hash {
         hash160::Hash::hash(&self.serialize())
@@ -172,6 +179,7 @@ impl MiniscriptKey for bitcoin::PublicKey {
     }
 
     type Hash = hash160::Hash;
+    type Sha256 = sha256::Hash;
 
     fn to_pubkeyhash(&self) -> Self::Hash {
         hash160::Hash::hash(&self.to_bytes())
@@ -180,6 +188,7 @@ impl MiniscriptKey for bitcoin::PublicKey {
 
 impl MiniscriptKey for bitcoin::secp256k1::XOnlyPublicKey {
     type Hash = hash160::Hash;
+    type Sha256 = sha256::Hash;
 
     fn to_pubkeyhash(&self) -> Self::Hash {
         hash160::Hash::hash(&self.serialize())
@@ -192,6 +201,7 @@ impl MiniscriptKey for bitcoin::secp256k1::XOnlyPublicKey {
 
 impl MiniscriptKey for String {
     type Hash = String;
+    type Sha256 = String; // specify hashes as string
 
     fn to_pubkeyhash(&self) -> Self::Hash {
         (&self).to_string()
@@ -216,6 +226,9 @@ pub trait ToPublicKey: MiniscriptKey {
     /// should give the same result as calling `to_public_key` and hashing
     /// the result directly.
     fn hash_to_hash160(hash: &<Self as MiniscriptKey>::Hash) -> hash160::Hash;
+
+    /// Converts the generic associated [`MiniscriptKey::Sha256`] to [`sha256::Hash`]
+    fn to_sha256(hash: &<Self as MiniscriptKey>::Sha256) -> sha256::Hash;
 }
 
 impl ToPublicKey for bitcoin::PublicKey {
@@ -226,6 +239,10 @@ impl ToPublicKey for bitcoin::PublicKey {
     fn hash_to_hash160(hash: &hash160::Hash) -> hash160::Hash {
         *hash
     }
+
+    fn to_sha256(hash: &sha256::Hash) -> sha256::Hash {
+        *hash
+    }
 }
 
 impl ToPublicKey for bitcoin::secp256k1::PublicKey {
@@ -236,6 +253,10 @@ impl ToPublicKey for bitcoin::secp256k1::PublicKey {
     fn hash_to_hash160(hash: &hash160::Hash) -> hash160::Hash {
         *hash
     }
+
+    fn to_sha256(hash: &sha256::Hash) -> sha256::Hash {
+        *hash
+    }
 }
 
 impl ToPublicKey for bitcoin::secp256k1::XOnlyPublicKey {
@@ -255,6 +276,10 @@ impl ToPublicKey for bitcoin::secp256k1::XOnlyPublicKey {
     fn hash_to_hash160(hash: &hash160::Hash) -> hash160::Hash {
         *hash
     }
+
+    fn to_sha256(hash: &sha256::Hash) -> sha256::Hash {
+        *hash
+    }
 }
 
 /// Dummy key which de/serializes to the empty string; useful sometimes for testing
@@ -274,6 +299,7 @@ impl str::FromStr for DummyKey {
 
 impl MiniscriptKey for DummyKey {
     type Hash = DummyKeyHash;
+    type Sha256 = DummySha256Hash;
 
     fn to_pubkeyhash(&self) -> Self::Hash {
         DummyKeyHash
@@ -303,6 +329,11 @@ impl ToPublicKey for DummyKey {
     fn hash_to_hash160(_: &DummyKeyHash) -> hash160::Hash {
         hash160::Hash::from_str("f54a5851e9372b87810a8e60cdd2e7cfd80b6e31").unwrap()
     }
+
+    fn to_sha256(_hash: &DummySha256Hash) -> sha256::Hash {
+        sha256::Hash::from_str("50863ad64a87ae8a2fe83c1af1a8403cb53f53e486d8511dad8a04887e5b2352")
+            .unwrap()
+    }
 }
 
 /// Dummy keyhash which de/serializes to the empty string; useful sometimes for testing
@@ -332,134 +363,99 @@ impl hash::Hash for DummyKeyHash {
     }
 }
 
-/// Converts a descriptor using abstract keys to one using specific keys.
-///
-/// # Panics
-///
-/// If `fpk` returns an uncompressed key when converting to a segwit descriptor.
-/// To prevent this panic, ensure `fpk` returns an error in this case instead.
-pub trait TranslatePk<P, Q>
-where
-    P: MiniscriptKey,
-    Q: MiniscriptKey,
-{
-    /// The associated output type. This must be `Self<Q>`.
-    type Output;
-
-    /// Translates a struct from one generic to another where the translation
-    /// for Pk is provided by function `fpk`, and translation for PkH is
-    /// provided by function `fpkh`.
-    fn translate_pk<Fpk, Fpkh, E>(&self, fpk: Fpk, fpkh: Fpkh) -> Result<Self::Output, E>
-    where
-        Fpk: FnMut(&P) -> Result<Q, E>,
-        Fpkh: FnMut(&P::Hash) -> Result<Q::Hash, E>;
+/// Dummy keyhash which de/serializes to the empty string; useful for testing
+#[derive(Copy, Clone, PartialOrd, Ord, PartialEq, Eq, Debug)]
+pub struct DummySha256Hash;
 
-    /// Calls `Self::translate_pk` with conversion functions that cannot fail.
-    fn translate_pk_infallible<Fpk, Fpkh>(&self, mut fpk: Fpk, mut fpkh: Fpkh) -> Self::Output
-    where
-        Fpk: FnMut(&P) -> Q,
-        Fpkh: FnMut(&P::Hash) -> Q::Hash,
-    {
-        self.translate_pk::<_, _, ()>(|pk| Ok(fpk(pk)), |pkh| Ok(fpkh(pkh)))
-            .expect("infallible translation function")
+impl str::FromStr for DummySha256Hash {
+    type Err = &'static str;
+    fn from_str(x: &str) -> Result<DummySha256Hash, &'static str> {
+        if x.is_empty() {
+            Ok(DummySha256Hash)
+        } else {
+            Err("non empty dummy hash")
+        }
     }
 }
 
-/// Variant of `TranslatePk` where P and Q both have the same hash
-/// type, and the hashes can be converted by just cloning them.
-pub trait TranslatePk1<P, Q>: TranslatePk<P, Q>
-where
-    P: MiniscriptKey,
-    Q: MiniscriptKey<Hash = P::Hash>,
-{
-    /// Translates a struct from one generic to another where the translation
-    /// for Pk is provided by function `fpk`.
-    fn translate_pk1<Fpk, E>(&self, fpk: Fpk) -> Result<<Self as TranslatePk<P, Q>>::Output, E>
-    where
-        Fpk: FnMut(&P) -> Result<Q, E>,
-    {
-        self.translate_pk(fpk, |h| Ok(h.clone()))
+impl fmt::Display for DummySha256Hash {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        f.write_str("")
     }
+}
 
-    /// Translates a struct from one generic to another where the translation
-    /// for Pk is provided by function `fpk`.
-    fn translate_pk1_infallible<Fpk>(&self, fpk: Fpk) -> <Self as TranslatePk<P, Q>>::Output
-    where
-        Fpk: FnMut(&P) -> Q,
-    {
-        self.translate_pk_infallible(fpk, P::Hash::clone)
+impl hash::Hash for DummySha256Hash {
+    fn hash<H: hash::Hasher>(&self, state: &mut H) {
+        "DummySha256Hash".hash(state);
     }
 }
-impl<P, Q, T> TranslatePk1<P, Q> for T
+
+/// Describes an object that can translate various keys and hashes from one key to the type
+/// associated with the other key. Used by the [`TranslatePk`] trait to do the actual translations.
+pub trait Translator<P, Q, E>
 where
     P: MiniscriptKey,
-    Q: MiniscriptKey<Hash = P::Hash>,
-    T: TranslatePk<P, Q>,
+    Q: MiniscriptKey,
 {
+    /// Translates public keys P -> Q.
+    fn pk(&mut self, pk: &P) -> Result<Q, E>;
+
+    /// Translates public key hashes P::Hash -> Q::Hash.
+    fn pkh(&mut self, pkh: &P::Hash) -> Result<Q::Hash, E>;
+
+    /// Translates sha256 hashes from P::Sha256 -> Q::Sha256
+    fn sha256(&mut self, sha256: &P::Sha256) -> Result<Q::Sha256, E>;
 }
 
-/// Variant of `TranslatePk` where P's hash is P, so the hashes
-/// can be converted by reusing the key-conversion function.
-pub trait TranslatePk2<P, Q>: TranslatePk<P, Q>
+/// Provides the conversion information required in [`TranslatePk`].
+/// Same as [`Translator`], but useful when all the associated types apart
+/// from Pk/Pkh don't change in translation
+pub trait PkTranslator<P, Q, E>
 where
-    P: MiniscriptKey<Hash = P>,
-    Q: MiniscriptKey,
+    P: MiniscriptKey,
+    Q: MiniscriptKey<Sha256 = P::Sha256>,
 {
-    /// Translates a struct from one generic to another where the translation
-    /// for Pk is provided by function `fpk`.
-    fn translate_pk2<Fpk, E>(&self, fpk: Fpk) -> Result<<Self as TranslatePk<P, Q>>::Output, E>
-    where
-        Fpk: Fn(&P) -> Result<Q, E>,
-    {
-        self.translate_pk(&fpk, |h| fpk(h).map(|q| q.to_pubkeyhash()))
-    }
+    /// Provides the translation public keys P -> Q
+    fn pk(&mut self, pk: &P) -> Result<Q, E>;
 
-    /// Translates a struct from one generic to another where the translation
-    /// for Pk is provided by function `fpk`.
-    fn translate_pk2_infallible<Fpk>(&self, fpk: Fpk) -> <Self as TranslatePk<P, Q>>::Output
-    where
-        Fpk: Fn(&P) -> Q,
-    {
-        self.translate_pk_infallible(&fpk, |h| fpk(h).to_pubkeyhash())
-    }
+    /// Provides the translation public keys hashes P::Hash -> Q::Hash
+    fn pkh(&mut self, pkh: &P::Hash) -> Result<Q::Hash, E>;
 }
-impl<P, Q, T> TranslatePk2<P, Q> for T
+
+impl<P, Q, E, T> Translator<P, Q, E> for T
 where
-    P: MiniscriptKey<Hash = P>,
-    Q: MiniscriptKey,
-    T: TranslatePk<P, Q>,
+    T: PkTranslator<P, Q, E>,
+    P: MiniscriptKey,
+    Q: MiniscriptKey<Sha256 = P::Sha256>,
 {
-}
+    fn pk(&mut self, pk: &P) -> Result<Q, E> {
+        <Self as PkTranslator<P, Q, E>>::pk(self, pk)
+    }
 
-/// Variant of `TranslatePk` where Q's hash is `hash160` so we can
-/// derive hashes by calling `hash_to_hash160`.
-pub trait TranslatePk3<P: MiniscriptKey + ToPublicKey, Q: MiniscriptKey<Hash = hash160::Hash>>:
-    TranslatePk<P, Q>
-{
-    /// Translates a struct from one generic to another where the translation
-    /// for Pk is provided by function `fpk`.
-    fn translate_pk3<Fpk, E>(&self, fpk: Fpk) -> Result<<Self as TranslatePk<P, Q>>::Output, E>
-    where
-        Fpk: FnMut(&P) -> Result<Q, E>,
-    {
-        self.translate_pk(fpk, |h| Ok(P::hash_to_hash160(h)))
+    fn pkh(&mut self, pkh: &<P as MiniscriptKey>::Hash) -> Result<<Q as MiniscriptKey>::Hash, E> {
+        <Self as PkTranslator<P, Q, E>>::pkh(self, pkh)
     }
 
-    /// Translates a struct from one generic to another where the translation
-    /// for Pk is provided by function `fpk`.
-    fn translate_pk3_infallible<Fpk>(&self, fpk: Fpk) -> <Self as TranslatePk<P, Q>>::Output
-    where
-        Fpk: FnMut(&P) -> Q,
-    {
-        self.translate_pk_infallible(fpk, P::hash_to_hash160)
+    fn sha256(&mut self, sha256: &<P as MiniscriptKey>::Sha256) -> Result<<Q>::Sha256, E> {
+        Ok(sha256.clone())
     }
 }
-impl<P, Q, T> TranslatePk3<P, Q> for T
+
+/// Converts a descriptor using abstract keys to one using specific keys. Uses translator `t` to do
+/// the actual translation function calls.
+pub trait TranslatePk<P, Q>
 where
-    P: MiniscriptKey + ToPublicKey,
-    Q: MiniscriptKey<Hash = hash160::Hash>,
-    T: TranslatePk<P, Q>,
+    P: MiniscriptKey,
+    Q: MiniscriptKey,
 {
+    /// The associated output type. This must be `Self<Q>`.
+    type Output;
+
+    /// Translates a struct from one generic to another where the translations
+    /// for Pk are provided by the given [`Translator`].
+    fn translate_pk<T, E>(&self, translator: &mut T) -> Result<Self::Output, E>
+    where
+        T: Translator<P, Q, E>;
 }
 
 /// Either a key or a keyhash
@@ -658,18 +654,10 @@ impl fmt::Display for Error {
             Error::PubKeyCtxError(ref pk, ref ctx) => {
                 write!(f, "Pubkey error: {} under {} scriptcontext", pk, ctx)
             }
-            Error::MultiATooManyKeys(k) => {
-                write!(f, "MultiA too many keys {}", k)
-            }
-            Error::TaprootSpendInfoUnavialable => {
-                write!(f, "Taproot Spend Info not computed.")
-            }
-            Error::TrNoScriptCode => {
-                write!(f, "No script code for Tr descriptors")
-            }
-            Error::TrNoExplicitScript => {
-                write!(f, "No script code for Tr descriptors")
-            }
+            Error::MultiATooManyKeys(k) => write!(f, "MultiA too many keys {}", k),
+            Error::TaprootSpendInfoUnavialable => write!(f, "Taproot Spend Info not computed."),
+            Error::TrNoScriptCode => write!(f, "No script code for Tr descriptors"),
+            Error::TrNoExplicitScript => write!(f, "No script code for Tr descriptors"),
         }
     }
 }
diff --git a/src/macros.rs b/src/macros.rs
index b154919b3..7f59aa9a2 100644
--- a/src/macros.rs
+++ b/src/macros.rs
@@ -16,6 +16,88 @@ macro_rules! policy_str {
     ($($arg:tt)*) => ($crate::policy::Concrete::from_str(&format!($($arg)*)).unwrap())
 }
 
+/// Macro for implementing FromTree trait. This avoids copying all the Pk::Associated type bounds
+/// throughout the codebase.
+macro_rules! impl_from_tree {
+    ($(;$gen:ident; $gen_con:ident, )* $name: ty,
+        $(#[$meta:meta])*
+        fn $fn:ident ( $($arg:ident : $type:ty),* ) -> $ret:ty
+        $body:block
+    ) => {
+        impl<Pk $(, $gen)*> $crate::expression::FromTree for $name
+        where
+            Pk: MiniscriptKey + core::str::FromStr,
+            Pk::Hash: core::str::FromStr,
+            Pk::Sha256: core::str::FromStr,
+            <Pk as core::str::FromStr>::Err: $crate::prelude::ToString,
+            <<Pk as MiniscriptKey>::Hash as core::str::FromStr>::Err: $crate::prelude::ToString,
+            <<Pk as MiniscriptKey>::Sha256 as core::str::FromStr>::Err: $crate::prelude::ToString,
+            $($gen : $gen_con,)*
+            {
+
+                $(#[$meta])*
+                fn $fn($($arg: $type)* ) -> $ret {
+                    $body
+                }
+            }
+    };
+}
+
+/// Macro for implementing FromStr trait. This avoids copying all the Pk::Associated type bounds
+/// throughout the codebase.
+macro_rules! impl_from_str {
+    ($(;$gen:ident; $gen_con:ident, )* $name: ty,
+        type Err = $err_ty:ty;,
+        $(#[$meta:meta])*
+        fn $fn:ident ( $($arg:ident : $type:ty),* ) -> $ret:ty
+        $body:block
+    ) => {
+        impl<Pk $(, $gen)*> core::str::FromStr for $name
+        where
+            Pk: MiniscriptKey + core::str::FromStr,
+            Pk::Hash: core::str::FromStr,
+            Pk::Sha256: core::str::FromStr,
+            <Pk as core::str::FromStr>::Err: $crate::prelude::ToString,
+            <<Pk as MiniscriptKey>::Hash as core::str::FromStr>::Err: $crate::prelude::ToString,
+            <<Pk as MiniscriptKey>::Sha256 as core::str::FromStr>::Err: $crate::prelude::ToString,
+            $($gen : $gen_con,)*
+            {
+                type Err = $err_ty;
+
+                $(#[$meta])*
+                fn $fn($($arg: $type)* ) -> $ret {
+                    $body
+                }
+            }
+    };
+}
+
+/// Macro for impl Struct with associated bounds. This avoids copying all the Pk::Associated type bounds
+/// throughout the codebase.
+macro_rules! impl_block_str {
+    ($(;$gen:ident; $gen_con:ident, )* $name: ty,
+        $(#[$meta:meta])*
+        $v:vis fn $fn:ident ( $($arg:ident : $type:ty, )* ) -> $ret:ty
+        $body:block
+    ) => {
+        impl<Pk $(, $gen)*> $name
+        where
+            Pk: MiniscriptKey + core::str::FromStr,
+            Pk::Hash: core::str::FromStr,
+            Pk::Sha256: core::str::FromStr,
+            <Pk as core::str::FromStr>::Err: $crate::prelude::ToString,
+            <<Pk as MiniscriptKey>::Hash as core::str::FromStr>::Err: $crate::prelude::ToString,
+            <<Pk as MiniscriptKey>::Sha256 as core::str::FromStr>::Err: $crate::prelude::ToString,
+            $($gen : $gen_con,)*
+            {
+                $(#[$meta])*
+                $v fn $fn($($arg: $type,)* ) -> $ret {
+                    $body
+                }
+            }
+    };
+}
+
 /// A macro that implements serde serialization and deserialization using the
 /// `fmt::Display` and `str::FromStr` traits.
 macro_rules! serde_string_impl_pk {
@@ -25,9 +107,12 @@ macro_rules! serde_string_impl_pk {
         where
             Pk: $crate::MiniscriptKey + core::str::FromStr,
             Pk::Hash: core::str::FromStr,
+            Pk::Sha256: core::str::FromStr,
             <Pk as core::str::FromStr>::Err: core::fmt::Display,
             <<Pk as $crate::MiniscriptKey>::Hash as core::str::FromStr>::Err:
                 core::fmt::Display,
+            <<Pk as $crate::MiniscriptKey>::Sha256 as core::str::FromStr>::Err:
+                core::fmt::Display,
             $($gen : $gen_con,)*
         {
             fn deserialize<D>(deserializer: D) -> Result<$name<Pk $(, $gen)*>, D::Error>
@@ -44,9 +129,12 @@ macro_rules! serde_string_impl_pk {
                 where
                     Pk: $crate::MiniscriptKey + core::str::FromStr,
                     Pk::Hash: core::str::FromStr,
+                    Pk::Sha256: core::str::FromStr,
                     <Pk as core::str::FromStr>::Err: core::fmt::Display,
                     <<Pk as $crate::MiniscriptKey>::Hash as core::str::FromStr>::Err:
                         core::fmt::Display,
+                    <<Pk as $crate::MiniscriptKey>::Sha256 as core::str::FromStr>::Err:
+                        core::fmt::Display,
                     $($gen: $gen_con,)*
                 {
                     type Value = $name<Pk $(, $gen)*>;
diff --git a/src/miniscript/astelem.rs b/src/miniscript/astelem.rs
index e5cf13f74..932d5135e 100644
--- a/src/miniscript/astelem.rs
+++ b/src/miniscript/astelem.rs
@@ -19,12 +19,12 @@
 //! encoding in Bitcoin script, as well as a datatype. Full details
 //! are given on the Miniscript website.
 
+use core::fmt;
 use core::str::FromStr;
-use core::{fmt, str};
 
 use bitcoin::blockdata::{opcodes, script};
 use bitcoin::hashes::hex::FromHex;
-use bitcoin::hashes::{hash160, ripemd160, sha256, sha256d, Hash};
+use bitcoin::hashes::{hash160, ripemd160, sha256d, Hash};
 use sync::Arc;
 
 use crate::miniscript::context::SigType;
@@ -34,7 +34,7 @@ use crate::prelude::*;
 use crate::util::MsKeyBuilder;
 use crate::{
     errstr, expression, script_num_size, Error, ForEach, ForEachKey, Miniscript, MiniscriptKey,
-    Terminal, ToPublicKey, TranslatePk,
+    Terminal, ToPublicKey, TranslatePk, Translator,
 };
 
 impl<Pk: MiniscriptKey, Ctx: ScriptContext> Terminal<Pk, Ctx> {
@@ -67,16 +67,11 @@ where
     type Output = Terminal<Q, Ctx>;
 
     /// Converts an AST element with one public key type to one of another public key type.
-    ///
-    /// # Panics
-    ///
-    /// While converting to Segwit Miniscript using uncompressed public keys.
-    fn translate_pk<Fpk, Fpkh, E>(&self, mut fpk: Fpk, mut fpkh: Fpkh) -> Result<Self::Output, E>
+    fn translate_pk<T, E>(&self, translate: &mut T) -> Result<Self::Output, E>
     where
-        Fpk: FnMut(&Pk) -> Result<Q, E>,
-        Fpkh: FnMut(&Pk::Hash) -> Result<Q::Hash, E>,
+        T: Translator<Pk, Q, E>,
     {
-        self.real_translate_pk(&mut fpk, &mut fpkh)
+        self.real_translate_pk(translate)
     }
 }
 
@@ -127,87 +122,74 @@ impl<Pk: MiniscriptKey, Ctx: ScriptContext> Terminal<Pk, Ctx> {
         }
     }
 
-    pub(super) fn real_translate_pk<Fpk, Fpkh, Q, E, CtxQ>(
-        &self,
-        fpk: &mut Fpk,
-        fpkh: &mut Fpkh,
-    ) -> Result<Terminal<Q, CtxQ>, E>
+    pub(super) fn real_translate_pk<Q, CtxQ, T, E>(&self, t: &mut T) -> Result<Terminal<Q, CtxQ>, E>
     where
-        Fpk: FnMut(&Pk) -> Result<Q, E>,
-        Fpkh: FnMut(&Pk::Hash) -> Result<Q::Hash, E>,
         Q: MiniscriptKey,
         CtxQ: ScriptContext,
+        T: Translator<Pk, Q, E>,
     {
         let frag: Terminal<Q, CtxQ> = match *self {
-            Terminal::PkK(ref p) => Terminal::PkK(fpk(p)?),
-            Terminal::PkH(ref p) => Terminal::PkH(fpkh(p)?),
+            Terminal::PkK(ref p) => Terminal::PkK(t.pk(p)?),
+            Terminal::PkH(ref p) => Terminal::PkH(t.pkh(p)?),
             Terminal::After(n) => Terminal::After(n),
             Terminal::Older(n) => Terminal::Older(n),
-            Terminal::Sha256(x) => Terminal::Sha256(x),
+            Terminal::Sha256(ref x) => Terminal::Sha256(t.sha256(&x)?),
             Terminal::Hash256(x) => Terminal::Hash256(x),
             Terminal::Ripemd160(x) => Terminal::Ripemd160(x),
             Terminal::Hash160(x) => Terminal::Hash160(x),
             Terminal::True => Terminal::True,
             Terminal::False => Terminal::False,
-            Terminal::Alt(ref sub) => Terminal::Alt(Arc::new(sub.real_translate_pk(fpk, fpkh)?)),
-            Terminal::Swap(ref sub) => Terminal::Swap(Arc::new(sub.real_translate_pk(fpk, fpkh)?)),
-            Terminal::Check(ref sub) => {
-                Terminal::Check(Arc::new(sub.real_translate_pk(fpk, fpkh)?))
-            }
-            Terminal::DupIf(ref sub) => {
-                Terminal::DupIf(Arc::new(sub.real_translate_pk(fpk, fpkh)?))
-            }
-            Terminal::Verify(ref sub) => {
-                Terminal::Verify(Arc::new(sub.real_translate_pk(fpk, fpkh)?))
-            }
-            Terminal::NonZero(ref sub) => {
-                Terminal::NonZero(Arc::new(sub.real_translate_pk(fpk, fpkh)?))
-            }
+            Terminal::Alt(ref sub) => Terminal::Alt(Arc::new(sub.real_translate_pk(t)?)),
+            Terminal::Swap(ref sub) => Terminal::Swap(Arc::new(sub.real_translate_pk(t)?)),
+            Terminal::Check(ref sub) => Terminal::Check(Arc::new(sub.real_translate_pk(t)?)),
+            Terminal::DupIf(ref sub) => Terminal::DupIf(Arc::new(sub.real_translate_pk(t)?)),
+            Terminal::Verify(ref sub) => Terminal::Verify(Arc::new(sub.real_translate_pk(t)?)),
+            Terminal::NonZero(ref sub) => Terminal::NonZero(Arc::new(sub.real_translate_pk(t)?)),
             Terminal::ZeroNotEqual(ref sub) => {
-                Terminal::ZeroNotEqual(Arc::new(sub.real_translate_pk(fpk, fpkh)?))
+                Terminal::ZeroNotEqual(Arc::new(sub.real_translate_pk(t)?))
             }
             Terminal::AndV(ref left, ref right) => Terminal::AndV(
-                Arc::new(left.real_translate_pk(&mut *fpk, &mut *fpkh)?),
-                Arc::new(right.real_translate_pk(fpk, fpkh)?),
+                Arc::new(left.real_translate_pk(t)?),
+                Arc::new(right.real_translate_pk(t)?),
             ),
             Terminal::AndB(ref left, ref right) => Terminal::AndB(
-                Arc::new(left.real_translate_pk(&mut *fpk, &mut *fpkh)?),
-                Arc::new(right.real_translate_pk(fpk, fpkh)?),
+                Arc::new(left.real_translate_pk(t)?),
+                Arc::new(right.real_translate_pk(t)?),
             ),
             Terminal::AndOr(ref a, ref b, ref c) => Terminal::AndOr(
-                Arc::new(a.real_translate_pk(&mut *fpk, &mut *fpkh)?),
-                Arc::new(b.real_translate_pk(&mut *fpk, &mut *fpkh)?),
-                Arc::new(c.real_translate_pk(fpk, fpkh)?),
+                Arc::new(a.real_translate_pk(t)?),
+                Arc::new(b.real_translate_pk(t)?),
+                Arc::new(c.real_translate_pk(t)?),
             ),
             Terminal::OrB(ref left, ref right) => Terminal::OrB(
-                Arc::new(left.real_translate_pk(&mut *fpk, &mut *fpkh)?),
-                Arc::new(right.real_translate_pk(fpk, fpkh)?),
+                Arc::new(left.real_translate_pk(t)?),
+                Arc::new(right.real_translate_pk(t)?),
             ),
             Terminal::OrD(ref left, ref right) => Terminal::OrD(
-                Arc::new(left.real_translate_pk(&mut *fpk, &mut *fpkh)?),
-                Arc::new(right.real_translate_pk(fpk, fpkh)?),
+                Arc::new(left.real_translate_pk(t)?),
+                Arc::new(right.real_translate_pk(t)?),
             ),
             Terminal::OrC(ref left, ref right) => Terminal::OrC(
-                Arc::new(left.real_translate_pk(&mut *fpk, &mut *fpkh)?),
-                Arc::new(right.real_translate_pk(fpk, fpkh)?),
+                Arc::new(left.real_translate_pk(t)?),
+                Arc::new(right.real_translate_pk(t)?),
             ),
             Terminal::OrI(ref left, ref right) => Terminal::OrI(
-                Arc::new(left.real_translate_pk(&mut *fpk, &mut *fpkh)?),
-                Arc::new(right.real_translate_pk(fpk, fpkh)?),
+                Arc::new(left.real_translate_pk(t)?),
+                Arc::new(right.real_translate_pk(t)?),
             ),
             Terminal::Thresh(k, ref subs) => {
                 let subs: Result<Vec<Arc<Miniscript<Q, _>>>, _> = subs
                     .iter()
-                    .map(|s| s.real_translate_pk(&mut *fpk, &mut *fpkh).map(Arc::new))
+                    .map(|s| s.real_translate_pk(t).map(Arc::new))
                     .collect();
                 Terminal::Thresh(k, subs?)
             }
             Terminal::Multi(k, ref keys) => {
-                let keys: Result<Vec<Q>, _> = keys.iter().map(&mut *fpk).collect();
+                let keys: Result<Vec<Q>, _> = keys.iter().map(|k| t.pk(k)).collect();
                 Terminal::Multi(k, keys?)
             }
             Terminal::MultiA(k, ref keys) => {
-                let keys: Result<Vec<Q>, _> = keys.iter().map(&mut *fpk).collect();
+                let keys: Result<Vec<Q>, _> = keys.iter().map(|k| t.pk(k)).collect();
                 Terminal::MultiA(k, keys?)
             }
         };
@@ -276,7 +258,7 @@ impl<Pk: MiniscriptKey, Ctx: ScriptContext> fmt::Debug for Terminal<Pk, Ctx> {
                 Terminal::PkH(ref pkh) => write!(f, "pk_h({:?})", pkh),
                 Terminal::After(t) => write!(f, "after({})", t),
                 Terminal::Older(t) => write!(f, "older({})", t),
-                Terminal::Sha256(h) => write!(f, "sha256({})", h),
+                Terminal::Sha256(ref h) => write!(f, "sha256({})", h),
                 Terminal::Hash256(h) => {
                     let mut x = h.into_inner();
                     x.reverse();
@@ -333,7 +315,7 @@ impl<Pk: MiniscriptKey, Ctx: ScriptContext> fmt::Display for Terminal<Pk, Ctx> {
             Terminal::PkH(ref pkh) => write!(f, "pk_h({})", pkh),
             Terminal::After(t) => write!(f, "after({})", t),
             Terminal::Older(t) => write!(f, "older({})", t),
-            Terminal::Sha256(h) => write!(f, "sha256({})", h),
+            Terminal::Sha256(ref h) => write!(f, "sha256({})", h),
             Terminal::Hash256(h) => {
                 let mut x = h.into_inner();
                 x.reverse();
@@ -418,27 +400,17 @@ impl<Pk: MiniscriptKey, Ctx: ScriptContext> fmt::Display for Terminal<Pk, Ctx> {
     }
 }
 
-impl<Pk, Ctx> expression::FromTree for Arc<Terminal<Pk, Ctx>>
-where
-    Pk: MiniscriptKey + str::FromStr,
-    Pk::Hash: str::FromStr,
-    Ctx: ScriptContext,
-    <Pk as str::FromStr>::Err: ToString,
-    <<Pk as MiniscriptKey>::Hash as str::FromStr>::Err: ToString,
-{
+impl_from_tree!(
+    ;Ctx; ScriptContext,
+    Arc<Terminal<Pk, Ctx>>,
     fn from_tree(top: &expression::Tree) -> Result<Arc<Terminal<Pk, Ctx>>, Error> {
         Ok(Arc::new(expression::FromTree::from_tree(top)?))
     }
-}
+);
 
-impl<Pk, Ctx> expression::FromTree for Terminal<Pk, Ctx>
-where
-    Pk: MiniscriptKey + str::FromStr,
-    Pk::Hash: str::FromStr,
-    Ctx: ScriptContext,
-    <Pk as str::FromStr>::Err: ToString,
-    <<Pk as MiniscriptKey>::Hash as str::FromStr>::Err: ToString,
-{
+impl_from_tree!(
+    ;Ctx; ScriptContext,
+    Terminal<Pk, Ctx>,
     fn from_tree(top: &expression::Tree) -> Result<Terminal<Pk, Ctx>, Error> {
         let mut aliased_wrap;
         let frag_name;
@@ -498,7 +470,7 @@ where
                 expression::parse_num(x).map(Terminal::Older)
             }),
             ("sha256", 1) => expression::terminal(&top.args[0], |x| {
-                sha256::Hash::from_hex(x).map(Terminal::Sha256)
+                Pk::Sha256::from_str(x).map(Terminal::Sha256)
             }),
             ("hash256", 1) => expression::terminal(&top.args[0], |x| {
                 sha256d::Hash::from_hex(x)
@@ -620,7 +592,7 @@ where
         Ctx::check_global_validity(&ms)?;
         Ok(ms.node)
     }
-}
+);
 
 /// Helper trait to add a `push_astelem` method to `script::Builder`
 trait PushAstElem<Pk: MiniscriptKey, Ctx: ScriptContext> {
@@ -657,12 +629,12 @@ impl<Pk: MiniscriptKey, Ctx: ScriptContext> Terminal<Pk, Ctx> {
                 .push_int(t as i64)
                 .push_opcode(opcodes::all::OP_CLTV),
             Terminal::Older(t) => builder.push_int(t as i64).push_opcode(opcodes::all::OP_CSV),
-            Terminal::Sha256(h) => builder
+            Terminal::Sha256(ref h) => builder
                 .push_opcode(opcodes::all::OP_SIZE)
                 .push_int(32)
                 .push_opcode(opcodes::all::OP_EQUALVERIFY)
                 .push_opcode(opcodes::all::OP_SHA256)
-                .push_slice(&h[..])
+                .push_slice(&Pk::to_sha256(&h))
                 .push_opcode(opcodes::all::OP_EQUAL),
             Terminal::Hash256(h) => builder
                 .push_opcode(opcodes::all::OP_SIZE)
diff --git a/src/miniscript/context.rs b/src/miniscript/context.rs
index 8d0c451b8..9aeb2563c 100644
--- a/src/miniscript/context.rs
+++ b/src/miniscript/context.rs
@@ -191,6 +191,7 @@ pub trait ScriptContext:
     fmt::Debug + Clone + Ord + PartialOrd + Eq + PartialEq + hash::Hash + private::Sealed
 where
     Self::Key: MiniscriptKey<Hash = bitcoin::hashes::hash160::Hash>,
+    Self::Key: MiniscriptKey<Sha256 = bitcoin::hashes::sha256::Hash>,
 {
     /// The consensus key associated with the type. Must be a parseable key
     type Key: ParseableKey;
diff --git a/src/miniscript/decode.rs b/src/miniscript/decode.rs
index 2e10139ae..f7a94d42b 100644
--- a/src/miniscript/decode.rs
+++ b/src/miniscript/decode.rs
@@ -142,7 +142,7 @@ pub enum Terminal<Pk: MiniscriptKey, Ctx: ScriptContext> {
     Older(u32),
     // hashlocks
     /// `SIZE 32 EQUALVERIFY SHA256 <hash> EQUAL`
-    Sha256(sha256::Hash),
+    Sha256(Pk::Sha256),
     /// `SIZE 32 EQUALVERIFY HASH256 <hash> EQUAL`
     Hash256(sha256d::Hash),
     /// `SIZE 32 EQUALVERIFY RIPEMD160 <hash> EQUAL`
diff --git a/src/miniscript/iter.rs b/src/miniscript/iter.rs
index 5207c0ce7..fc9e28044 100644
--- a/src/miniscript/iter.rs
+++ b/src/miniscript/iter.rs
@@ -121,7 +121,7 @@ impl<Pk: MiniscriptKey, Ctx: ScriptContext> Miniscript<Pk, Ctx> {
     /// NB: The function analyzes only single miniscript item and not any of its descendants in AST.
     /// To obtain a list of all public keys within AST use [Miniscript::iter_pk()] function, for example
     /// `miniscript.iter_pubkeys().collect()`.
-    pub fn get_leaf_pk(&self) -> Vec<Pk> {
+    pub fn get_leapk(&self) -> Vec<Pk> {
         match self.node {
             Terminal::PkK(ref key) => vec![key.clone()],
             Terminal::Multi(_, ref keys) | Terminal::MultiA(_, ref keys) => keys.clone(),
@@ -138,7 +138,7 @@ impl<Pk: MiniscriptKey, Ctx: ScriptContext> Miniscript<Pk, Ctx> {
     /// NB: The function analyzes only single miniscript item and not any of its descendants in AST.
     /// To obtain a list of all public key hashes within AST use [Miniscript::iter_pkh()] function,
     /// for example `miniscript.iter_pubkey_hashes().collect()`.
-    pub fn get_leaf_pkh(&self) -> Vec<Pk::Hash> {
+    pub fn get_leapkh(&self) -> Vec<Pk::Hash> {
         match self.node {
             Terminal::PkH(ref hash) => vec![hash.clone()],
             Terminal::PkK(ref key) => vec![key.to_pubkeyhash()],
@@ -156,7 +156,7 @@ impl<Pk: MiniscriptKey, Ctx: ScriptContext> Miniscript<Pk, Ctx> {
     /// NB: The function analyzes only single miniscript item and not any of its descendants in AST.
     /// To obtain a list of all public keys or hashes within AST use [Miniscript::iter_pk_pkh()]
     /// function, for example `miniscript.iter_pubkeys_and_hashes().collect()`.
-    pub fn get_leaf_pk_pkh(&self) -> Vec<PkPkh<Pk>> {
+    pub fn get_leapk_pkh(&self) -> Vec<PkPkh<Pk>> {
         match self.node {
             Terminal::PkH(ref hash) => vec![PkPkh::HashedPubkey(hash.clone())],
             Terminal::PkK(ref key) => vec![PkPkh::PlainPubkey(key.clone())],
@@ -605,7 +605,7 @@ pub mod test {
                     return;
                 }
                 let ms = *ms.branches().first().unwrap_or(&&ms);
-                assert_eq!(ms.get_leaf_pk(), k);
+                assert_eq!(ms.get_leapk(), k);
             })
     }
 
@@ -624,7 +624,7 @@ pub mod test {
                     .collect();
                 // In our test cases we always have plain keys going first
                 all.extend(h);
-                assert_eq!(ms.get_leaf_pkh(), all);
+                assert_eq!(ms.get_leapkh(), all);
             })
     }
 
@@ -642,7 +642,7 @@ pub mod test {
                 } else {
                     k.into_iter().map(|k| PkPkh::PlainPubkey(k)).collect()
                 };
-                assert_eq!(ms.get_leaf_pk_pkh(), r);
+                assert_eq!(ms.get_leapk_pkh(), r);
             })
     }
 
diff --git a/src/miniscript/mod.rs b/src/miniscript/mod.rs
index 66d0b1f86..08c7f75d6 100644
--- a/src/miniscript/mod.rs
+++ b/src/miniscript/mod.rs
@@ -53,8 +53,9 @@ pub use crate::miniscript::context::ScriptContext;
 use crate::miniscript::decode::Terminal;
 use crate::miniscript::types::extra_props::ExtData;
 use crate::miniscript::types::Type;
-use crate::{expression, Error, ForEach, ForEachKey, MiniscriptKey, ToPublicKey, TranslatePk};
-
+use crate::{
+    expression, Error, ForEach, ForEachKey, MiniscriptKey, ToPublicKey, TranslatePk, Translator,
+};
 #[cfg(test)]
 mod ms_tests;
 
@@ -288,23 +289,12 @@ where
     type Output = Miniscript<Q, Ctx>;
 
     /// Translates a struct from one generic to another where the translation
-    /// for Pk is provided by function `fpk`, and translation for PkH is
-    /// provided by function `fpkh`.
-    ///
-    /// # Panics
-    ///
-    /// If `fpk` returns an uncompressed key when converting to a Segwit descriptor.
-    /// To prevent this panic, ensure `fpk` returns an error in this case instead.
-    fn translate_pk<Fpk, Fpkh, FuncError>(
-        &self,
-        mut fpk: Fpk,
-        mut fpkh: Fpkh,
-    ) -> Result<Self::Output, FuncError>
+    /// for Pk is provided by [`Translator`]
+    fn translate_pk<T, E>(&self, translate: &mut T) -> Result<Self::Output, E>
     where
-        Fpk: FnMut(&Pk) -> Result<Q, FuncError>,
-        Fpkh: FnMut(&Pk::Hash) -> Result<Q::Hash, FuncError>,
+        T: Translator<Pk, Q, E>,
     {
-        self.real_translate_pk(&mut fpk, &mut fpkh)
+        self.real_translate_pk(translate)
     }
 }
 
@@ -317,18 +307,16 @@ impl<Pk: MiniscriptKey, Ctx: ScriptContext> Miniscript<Pk, Ctx> {
         self.node.real_for_each_key(pred)
     }
 
-    pub(crate) fn real_translate_pk<Fpk, Fpkh, Q, FuncError, CtxQ>(
+    pub(super) fn real_translate_pk<Q, CtxQ, T, FuncError>(
         &self,
-        fpk: &mut Fpk,
-        fpkh: &mut Fpkh,
+        t: &mut T,
     ) -> Result<Miniscript<Q, CtxQ>, FuncError>
     where
-        Fpk: FnMut(&Pk) -> Result<Q, FuncError>,
-        Fpkh: FnMut(&Pk::Hash) -> Result<Q::Hash, FuncError>,
         Q: MiniscriptKey,
         CtxQ: ScriptContext,
+        T: Translator<Pk, Q, FuncError>,
     {
-        let inner = self.node.real_translate_pk(fpk, fpkh)?;
+        let inner = self.node.real_translate_pk(t)?;
         let ms = Miniscript {
             //directly copying the type and ext is safe because translating public
             //key should not change any properties
@@ -339,7 +327,11 @@ impl<Pk: MiniscriptKey, Ctx: ScriptContext> Miniscript<Pk, Ctx> {
         };
         Ok(ms)
     }
+}
 
+impl_block_str!(
+    ;Ctx; ScriptContext,
+    Miniscript<Pk, Ctx>,
     /// Attempt to parse an insane(scripts don't clear sanity checks)
     /// from string into a Miniscript representation.
     /// Use this to parse scripts with repeated pubkeys, timelock mixing, malleable
@@ -347,12 +339,7 @@ impl<Pk: MiniscriptKey, Ctx: ScriptContext> Miniscript<Pk, Ctx> {
     /// Some of the analysis guarantees of miniscript are lost when dealing with
     /// insane scripts. In general, in a multi-party setting users should only
     /// accept sane scripts.
-    pub fn from_str_insane(s: &str) -> Result<Miniscript<Pk, Ctx>, Error>
-    where
-        Pk: str::FromStr,
-        Pk::Hash: str::FromStr,
-        <Pk as str::FromStr>::Err: ToString,
-        <<Pk as MiniscriptKey>::Hash as str::FromStr>::Err: ToString,
+    pub fn from_str_insane(s: &str,) -> Result<Miniscript<Pk, Ctx>, Error>
     {
         // This checks for invalid ASCII chars
         let top = expression::Tree::from_str(s)?;
@@ -364,7 +351,7 @@ impl<Pk: MiniscriptKey, Ctx: ScriptContext> Miniscript<Pk, Ctx> {
             Ok(ms)
         }
     }
-}
+);
 
 impl<Pk: MiniscriptKey, Ctx: ScriptContext> Miniscript<Pk, Ctx> {
     /// Attempt to produce non-malleable satisfying witness for the
@@ -417,27 +404,17 @@ impl<Pk: MiniscriptKey, Ctx: ScriptContext> Miniscript<Pk, Ctx> {
     }
 }
 
-impl<Pk, Ctx> expression::FromTree for Arc<Miniscript<Pk, Ctx>>
-where
-    Pk: MiniscriptKey + str::FromStr,
-    Pk::Hash: str::FromStr,
-    Ctx: ScriptContext,
-    <Pk as str::FromStr>::Err: ToString,
-    <<Pk as MiniscriptKey>::Hash as str::FromStr>::Err: ToString,
-{
+impl_from_tree!(
+    ;Ctx; ScriptContext,
+    Arc<Miniscript<Pk, Ctx>>,
     fn from_tree(top: &expression::Tree) -> Result<Arc<Miniscript<Pk, Ctx>>, Error> {
         Ok(Arc::new(expression::FromTree::from_tree(top)?))
     }
-}
+);
 
-impl<Pk, Ctx> expression::FromTree for Miniscript<Pk, Ctx>
-where
-    Pk: MiniscriptKey + str::FromStr,
-    Pk::Hash: str::FromStr,
-    Ctx: ScriptContext,
-    <Pk as str::FromStr>::Err: ToString,
-    <<Pk as MiniscriptKey>::Hash as str::FromStr>::Err: ToString,
-{
+impl_from_tree!(
+    ;Ctx; ScriptContext,
+    Miniscript<Pk, Ctx>,
     /// Parse an expression tree into a Miniscript. As a general rule, this
     /// should not be called directly; rather go through the descriptor API.
     fn from_tree(top: &expression::Tree) -> Result<Miniscript<Pk, Ctx>, Error> {
@@ -449,27 +426,21 @@ where
             phantom: PhantomData,
         })
     }
-}
-
-/// Parse a Miniscript from string and perform sanity checks
-/// See [Miniscript::from_str_insane] to parse scripts from string that
-/// do not clear the [Miniscript::sanity_check] checks.
-impl<Pk, Ctx> str::FromStr for Miniscript<Pk, Ctx>
-where
-    Pk: MiniscriptKey + str::FromStr,
-    Pk::Hash: str::FromStr,
-    Ctx: ScriptContext,
-    <Pk as str::FromStr>::Err: ToString,
-    <<Pk as MiniscriptKey>::Hash as str::FromStr>::Err: ToString,
-{
-    type Err = Error;
-
+);
+
+impl_from_str!(
+    ;Ctx; ScriptContext,
+    Miniscript<Pk, Ctx>,
+    type Err = Error;,
+    /// Parse a Miniscript from string and perform sanity checks
+    /// See [Miniscript::from_str_insane] to parse scripts from string that
+    /// do not clear the [Miniscript::sanity_check] checks.
     fn from_str(s: &str) -> Result<Miniscript<Pk, Ctx>, Error> {
         let ms = Self::from_str_insane(s)?;
         ms.sanity_check()?;
         Ok(ms)
     }
-}
+);
 
 serde_string_impl_pk!(Miniscript, "a miniscript", Ctx; ScriptContext);
 
@@ -491,10 +462,8 @@ mod tests {
     use crate::miniscript::Terminal;
     use crate::policy::Liftable;
     use crate::prelude::*;
-    use crate::{
-        hex_script, DummyKey, DummyKeyHash, MiniscriptKey, Satisfier, ToPublicKey, TranslatePk,
-        TranslatePk1, TranslatePk2,
-    };
+    use crate::test_utils::{StrKeyTranslator, StrXOnlyKeyTranslator};
+    use crate::{hex_script, DummyKey, DummyKeyHash, Satisfier, ToPublicKey, TranslatePk};
 
     type Segwitv0Script = Miniscript<bitcoin::PublicKey, Segwitv0>;
     type Tapscript = Miniscript<bitcoin::secp256k1::XOnlyPublicKey, Tap>;
@@ -520,19 +489,11 @@ mod tests {
         ret
     }
 
-    fn string_rtt<Pk, Ctx, Str1, Str2>(
-        script: Miniscript<Pk, Ctx>,
-        expected_debug: Str1,
-        expected_display: Str2,
-    ) where
-        Pk: MiniscriptKey + str::FromStr,
-        Pk::Hash: str::FromStr,
-        Ctx: ScriptContext,
-        <Pk as str::FromStr>::Err: ToString,
-        <<Pk as MiniscriptKey>::Hash as str::FromStr>::Err: ToString,
-        Str1: Into<Option<&'static str>>,
-        Str2: Into<Option<&'static str>>,
-    {
+    fn string_rtt<Ctx: ScriptContext>(
+        script: Miniscript<bitcoin::PublicKey, Ctx>,
+        expected_debug: &str,
+        expected_display: &str,
+    ) {
         assert_eq!(script.ty.corr.base, types::Base::B);
         let debug = format!("{:?}", script);
         let display = format!("{}", script);
@@ -544,12 +505,24 @@ mod tests {
         }
         let roundtrip = Miniscript::from_str(&display).expect("parse string serialization");
         assert_eq!(roundtrip, script);
+    }
 
-        let translated = script.translate_pk_infallible(Pk::clone, Pk::Hash::clone);
-        assert_eq!(translated, script);
-
-        let translated = script.translate_pk1_infallible(Pk::clone);
-        assert_eq!(translated, script);
+    fn dummy_string_rtt<Ctx: ScriptContext>(
+        script: Miniscript<DummyKey, Ctx>,
+        expected_debug: &str,
+        expected_display: &str,
+    ) {
+        assert_eq!(script.ty.corr.base, types::Base::B);
+        let debug = format!("{:?}", script);
+        let display = format!("{}", script);
+        if let Some(expected) = expected_debug.into() {
+            assert_eq!(debug, expected);
+        }
+        if let Some(expected) = expected_display.into() {
+            assert_eq!(display, expected);
+        }
+        let roundtrip = Miniscript::from_str(&display).expect("parse string serialization");
+        assert_eq!(roundtrip, script);
     }
 
     fn script_rtt<Str1: Into<Option<&'static str>>>(script: Segwitv0Script, expected_hex: Str1) {
@@ -665,7 +638,7 @@ mod tests {
             ext: ExtData::cast_check(ExtData::from_pk_k::<Segwitv0>()).unwrap(),
             phantom: PhantomData,
         };
-        string_rtt(pkk_ms, "[B/onduesm]c:[K/onduesm]pk_k(DummyKey)", "pk()");
+        dummy_string_rtt(pkk_ms, "[B/onduesm]c:[K/onduesm]pk_k(DummyKey)", "pk()");
 
         let pkh_ms: Miniscript<DummyKey, Segwitv0> = Miniscript {
             node: Terminal::Check(Arc::new(Miniscript {
@@ -678,7 +651,7 @@ mod tests {
             ext: ExtData::cast_check(ExtData::from_pk_h::<Segwitv0>()).unwrap(),
             phantom: PhantomData,
         };
-        string_rtt(pkh_ms, "[B/nduesm]c:[K/nduesm]pk_h(DummyKeyHash)", "pkh()");
+        dummy_string_rtt(pkh_ms, "[B/nduesm]c:[K/nduesm]pk_h(DummyKeyHash)", "pkh()");
 
         let pkk_ms: Segwitv0Script = Miniscript {
             node: Terminal::Check(Arc::new(Miniscript {
@@ -1048,12 +1021,9 @@ mod tests {
         assert_eq!(tap_multi_a_ms.to_string(), "multi_a(1,A,B,C)");
 
         // Test encode/decode and translation tests
-        let tap_ms = tap_multi_a_ms.translate_pk2_infallible(|_| {
-            XOnlyPublicKey::from_str(
-                "e948a0bbf8b15ee47cf0851afbce8835b5f06d3003b8e7ed6104e82a1d41d6f8",
-            )
-            .unwrap()
-        });
+        let tap_ms = tap_multi_a_ms
+            .translate_pk(&mut StrXOnlyKeyTranslator::new())
+            .unwrap();
         // script rtt test
         assert_eq!(
             Miniscript::<XOnlyPublicKey, Tap>::parse_insane(&tap_ms.encode()).unwrap(),
@@ -1092,15 +1062,7 @@ mod tests {
             "and_b(1,s:and_v(v:older(9),c:pk_k(A)))",
         )
         .unwrap();
-        let ms_trans = ms.translate_pk_infallible(
-            |_x| {
-                bitcoin::PublicKey::from_str(
-                    "02fbcf092916824cc56c4591abeedd54586f5ffc73c6ba88118162e3500ad695ea",
-                )
-                .unwrap()
-            },
-            |_x| unreachable!(),
-        );
+        let ms_trans = ms.translate_pk(&mut StrKeyTranslator::new()).unwrap();
         let enc = ms_trans.encode();
         let ms = Miniscript::<bitcoin::PublicKey, Segwitv0>::parse_insane(&enc).unwrap();
         assert_eq!(ms_trans.encode(), ms.encode());
diff --git a/src/miniscript/satisfy.rs b/src/miniscript/satisfy.rs
index 6f74ab61a..be1b477da 100644
--- a/src/miniscript/satisfy.rs
+++ b/src/miniscript/satisfy.rs
@@ -21,7 +21,7 @@
 use core::{cmp, i64, mem};
 
 use bitcoin;
-use bitcoin::hashes::{hash160, ripemd160, sha256, sha256d};
+use bitcoin::hashes::{hash160, ripemd160, sha256d};
 use bitcoin::secp256k1::XOnlyPublicKey;
 use bitcoin::util::taproot::{ControlBlock, LeafVersion, TapLeafHash};
 use sync::Arc;
@@ -90,7 +90,7 @@ pub trait Satisfier<Pk: MiniscriptKey + ToPublicKey> {
     }
 
     /// Given a SHA256 hash, look up its preimage
-    fn lookup_sha256(&self, _: sha256::Hash) -> Option<Preimage32> {
+    fn lookup_sha256(&self, _: &Pk::Sha256) -> Option<Preimage32> {
         None
     }
 
@@ -257,7 +257,7 @@ impl<'a, Pk: MiniscriptKey + ToPublicKey, S: Satisfier<Pk>> Satisfier<Pk> for &'
         (**self).lookup_tap_control_block_map()
     }
 
-    fn lookup_sha256(&self, h: sha256::Hash) -> Option<Preimage32> {
+    fn lookup_sha256(&self, h: &Pk::Sha256) -> Option<Preimage32> {
         (**self).lookup_sha256(h)
     }
 
@@ -319,7 +319,7 @@ impl<'a, Pk: MiniscriptKey + ToPublicKey, S: Satisfier<Pk>> Satisfier<Pk> for &'
         (**self).lookup_tap_control_block_map()
     }
 
-    fn lookup_sha256(&self, h: sha256::Hash) -> Option<Preimage32> {
+    fn lookup_sha256(&self, h: &Pk::Sha256) -> Option<Preimage32> {
         (**self).lookup_sha256(h)
     }
 
@@ -433,7 +433,7 @@ macro_rules! impl_tuple_satisfier {
                 None
             }
 
-            fn lookup_sha256(&self, h: sha256::Hash) -> Option<Preimage32> {
+            fn lookup_sha256(&self, h: &Pk::Sha256) -> Option<Preimage32> {
                 let &($(ref $ty,)*) = self;
                 $(
                     if let Some(result) = $ty.lookup_sha256(h) {
@@ -601,7 +601,7 @@ impl Witness {
     }
 
     /// Turn a hash preimage into (part of) a satisfaction
-    fn sha256_preimage<Pk: ToPublicKey, S: Satisfier<Pk>>(sat: S, h: sha256::Hash) -> Self {
+    fn sha256_preimage<Pk: ToPublicKey, S: Satisfier<Pk>>(sat: S, h: &Pk::Sha256) -> Self {
         match sat.lookup_sha256(h) {
             Some(pre) => Witness::Stack(vec![pre.to_vec()]),
             // Note hash preimages are unavailable instead of impossible
@@ -981,7 +981,7 @@ impl Satisfaction {
                 stack: Witness::hash160_preimage(stfr, h),
                 has_sig: false,
             },
-            Terminal::Sha256(h) => Satisfaction {
+            Terminal::Sha256(ref h) => Satisfaction {
                 stack: Witness::sha256_preimage(stfr, h),
                 has_sig: false,
             },
diff --git a/src/policy/compiler.rs b/src/policy/compiler.rs
index 90eec0e38..79e76d0d9 100644
--- a/src/policy/compiler.rs
+++ b/src/policy/compiler.rs
@@ -845,7 +845,10 @@ where
         }
         Concrete::After(n) => insert_wrap!(AstElemExt::terminal(Terminal::After(n))),
         Concrete::Older(n) => insert_wrap!(AstElemExt::terminal(Terminal::Older(n))),
-        Concrete::Sha256(hash) => insert_wrap!(AstElemExt::terminal(Terminal::Sha256(hash))),
+        Concrete::Sha256(ref hash) => {
+            insert_wrap!(AstElemExt::terminal(Terminal::Sha256(hash.clone())))
+        }
+        // Satisfaction-cost + script-cost
         Concrete::Hash256(hash) => insert_wrap!(AstElemExt::terminal(Terminal::Hash256(hash))),
         Concrete::Ripemd160(hash) => insert_wrap!(AstElemExt::terminal(Terminal::Ripemd160(hash))),
         Concrete::Hash160(hash) => insert_wrap!(AstElemExt::terminal(Terminal::Hash160(hash))),
@@ -946,6 +949,8 @@ where
                 let r = best_compilations(policy_cache, &subs[1].1, rw * sat_prob, *dissat_prob)?;
                 r_comp.push(r);
             }
+
+            // or(sha256, pk)
             compile_binary!(&mut l_comp[0], &mut r_comp[0], [lw, rw], Terminal::OrB);
             compile_binary!(&mut r_comp[0], &mut l_comp[0], [rw, lw], Terminal::OrB);
 
diff --git a/src/policy/concrete.rs b/src/policy/concrete.rs
index f449b436b..a007ea881 100644
--- a/src/policy/concrete.rs
+++ b/src/policy/concrete.rs
@@ -20,7 +20,7 @@ use core::{fmt, str};
 use std::error;
 
 use bitcoin::hashes::hex::FromHex;
-use bitcoin::hashes::{hash160, ripemd160, sha256, sha256d};
+use bitcoin::hashes::{hash160, ripemd160, sha256d};
 #[cfg(feature = "compiler")]
 use {
     crate::descriptor::TapTree,
@@ -40,7 +40,7 @@ use crate::expression::{self, FromTree};
 use crate::miniscript::limits::{LOCKTIME_THRESHOLD, SEQUENCE_LOCKTIME_TYPE_FLAG};
 use crate::miniscript::types::extra_props::TimelockInfo;
 use crate::prelude::*;
-use crate::{errstr, Error, ForEach, ForEachKey, MiniscriptKey};
+use crate::{errstr, Error, ForEach, ForEachKey, MiniscriptKey, Translator};
 
 /// Concrete policy which corresponds directly to a Miniscript structure,
 /// and whose disjunctions are annotated with satisfaction probabilities
@@ -58,7 +58,7 @@ pub enum Policy<Pk: MiniscriptKey> {
     /// A relative locktime restriction
     Older(u32),
     /// A SHA256 whose preimage must be provided to satisfy the descriptor
-    Sha256(sha256::Hash),
+    Sha256(Pk::Sha256),
     /// A SHA256d whose preimage must be provided to satisfy the descriptor
     Hash256(sha256d::Hash),
     /// A RIPEMD160 whose preimage must be provided to satisfy the descriptor
@@ -326,39 +326,67 @@ impl<Pk: MiniscriptKey> Policy<Pk> {
     /// # Example
     ///
     /// ```
-    /// use miniscript::{bitcoin::PublicKey, policy::concrete::Policy};
+    /// use miniscript::{bitcoin::PublicKey, policy::concrete::Policy, Translator};
     /// use std::str::FromStr;
+    /// use std::collections::HashMap;
+    /// use miniscript::bitcoin::hashes::{sha256, hash160};
     /// let alice_key = "0270cf3c71f65a3d93d285d9149fddeeb638f87a2d4d8cf16c525f71c417439777";
     /// let bob_key = "02f43b15c50a436f5335dbea8a64dd3b4e63e34c3b50c42598acb5f4f336b5d2fb";
     /// let placeholder_policy = Policy::<String>::from_str("and(pk(alice_key),pk(bob_key))").unwrap();
     ///
-    /// let real_policy = placeholder_policy.translate_pk(|placeholder: &String| match placeholder.as_str() {
-    ///     "alice_key" => PublicKey::from_str(alice_key),
-    ///     "bob_key"   => PublicKey::from_str(bob_key),
-    ///     _ => panic!("unknown key!")
-    /// }).unwrap();
+    /// // Information to translator abstract String type keys to concrete bitcoin::PublicKey.
+    /// // In practice, wallets would map from String key names to BIP32 keys
+    /// struct StrPkTranslator {
+    ///     pk_map: HashMap<String, bitcoin::PublicKey>
+    /// }
+    ///
+    /// // If we also wanted to provide mapping of other associated types(sha256, older etc),
+    /// // we would use the general Translator Trait.
+    /// impl Translator<String, bitcoin::PublicKey, ()> for StrPkTranslator {
+    ///     // Provides the translation public keys P -> Q
+    ///     fn pk(&mut self, pk: &String) -> Result<bitcoin::PublicKey, ()> {
+    ///         self.pk_map.get(pk).copied().ok_or(()) // Dummy Err
+    ///     }
+    ///
+    ///     // If our policy also contained other fragments, we could provide the translation here.
+    ///     fn pkh(&mut self, pkh: &String) -> Result<hash160::Hash, ()> {
+    ///         unreachable!("Policy does not contain any pkh fragment");
+    ///     }
+    ///
+    ///     // If our policy also contained other fragments, we could provide the translation here.
+    ///     fn sha256(&mut self, sha256: &String) -> Result<sha256::Hash, ()> {
+    ///         unreachable!("Policy does not contain any sha256 fragment");
+    ///     }
+    /// }
+    ///
+    /// let mut pk_map = HashMap::new();
+    /// pk_map.insert(String::from("alice_key"), bitcoin::PublicKey::from_str(alice_key).unwrap());
+    /// pk_map.insert(String::from("bob_key"), bitcoin::PublicKey::from_str(bob_key).unwrap());
+    /// let mut t = StrPkTranslator { pk_map: pk_map };
+    ///
+    /// let real_policy = placeholder_policy.translate_pk(&mut t).unwrap();
     ///
     /// let expected_policy = Policy::from_str(&format!("and(pk({}),pk({}))", alice_key, bob_key)).unwrap();
     /// assert_eq!(real_policy, expected_policy);
     /// ```
-    pub fn translate_pk<Fpk, Q, E>(&self, mut fpk: Fpk) -> Result<Policy<Q>, E>
+    pub fn translate_pk<Q, E, T>(&self, t: &mut T) -> Result<Policy<Q>, E>
     where
-        Fpk: FnMut(&Pk) -> Result<Q, E>,
+        T: Translator<Pk, Q, E>,
         Q: MiniscriptKey,
     {
-        self._translate_pk(&mut fpk)
+        self._translate_pk(t)
     }
 
-    fn _translate_pk<Fpk, Q, E>(&self, fpk: &mut Fpk) -> Result<Policy<Q>, E>
+    fn _translate_pk<Q, E, T>(&self, t: &mut T) -> Result<Policy<Q>, E>
     where
-        Fpk: FnMut(&Pk) -> Result<Q, E>,
+        T: Translator<Pk, Q, E>,
         Q: MiniscriptKey,
     {
         match *self {
             Policy::Unsatisfiable => Ok(Policy::Unsatisfiable),
             Policy::Trivial => Ok(Policy::Trivial),
-            Policy::Key(ref pk) => fpk(pk).map(Policy::Key),
-            Policy::Sha256(ref h) => Ok(Policy::Sha256(*h)),
+            Policy::Key(ref pk) => t.pk(pk).map(Policy::Key),
+            Policy::Sha256(ref h) => t.sha256(h).map(Policy::Sha256),
             Policy::Hash256(ref h) => Ok(Policy::Hash256(*h)),
             Policy::Ripemd160(ref h) => Ok(Policy::Ripemd160(*h)),
             Policy::Hash160(ref h) => Ok(Policy::Hash160(*h)),
@@ -366,17 +394,17 @@ impl<Pk: MiniscriptKey> Policy<Pk> {
             Policy::Older(n) => Ok(Policy::Older(n)),
             Policy::Threshold(k, ref subs) => {
                 let new_subs: Result<Vec<Policy<Q>>, _> =
-                    subs.iter().map(|sub| sub._translate_pk(fpk)).collect();
+                    subs.iter().map(|sub| sub._translate_pk(t)).collect();
                 new_subs.map(|ok| Policy::Threshold(k, ok))
             }
             Policy::And(ref subs) => Ok(Policy::And(
                 subs.iter()
-                    .map(|sub| sub._translate_pk(fpk))
+                    .map(|sub| sub._translate_pk(t))
                     .collect::<Result<Vec<Policy<Q>>, E>>()?,
             )),
             Policy::Or(ref subs) => Ok(Policy::Or(
                 subs.iter()
-                    .map(|&(ref prob, ref sub)| Ok((*prob, sub._translate_pk(fpk)?)))
+                    .map(|&(ref prob, ref sub)| Ok((*prob, sub._translate_pk(t)?)))
                     .collect::<Result<Vec<(usize, Policy<Q>)>, E>>()?,
             )),
         }
@@ -601,7 +629,7 @@ impl<Pk: MiniscriptKey> fmt::Debug for Policy<Pk> {
             Policy::Key(ref pk) => write!(f, "pk({:?})", pk),
             Policy::After(n) => write!(f, "after({})", n),
             Policy::Older(n) => write!(f, "older({})", n),
-            Policy::Sha256(h) => write!(f, "sha256({})", h),
+            Policy::Sha256(ref h) => write!(f, "sha256({})", h),
             Policy::Hash256(h) => write!(f, "hash256({})", h),
             Policy::Ripemd160(h) => write!(f, "ripemd160({})", h),
             Policy::Hash160(h) => write!(f, "hash160({})", h),
@@ -644,7 +672,7 @@ impl<Pk: MiniscriptKey> fmt::Display for Policy<Pk> {
             Policy::Key(ref pk) => write!(f, "pk({})", pk),
             Policy::After(n) => write!(f, "after({})", n),
             Policy::Older(n) => write!(f, "older({})", n),
-            Policy::Sha256(h) => write!(f, "sha256({})", h),
+            Policy::Sha256(ref h) => write!(f, "sha256({})", h),
             Policy::Hash256(h) => write!(f, "hash256({})", h),
             Policy::Ripemd160(h) => write!(f, "ripemd160({})", h),
             Policy::Hash160(h) => write!(f, "hash160({})", h),
@@ -679,15 +707,9 @@ impl<Pk: MiniscriptKey> fmt::Display for Policy<Pk> {
     }
 }
 
-impl<Pk> str::FromStr for Policy<Pk>
-where
-    Pk: MiniscriptKey + str::FromStr,
-    Pk::Hash: str::FromStr,
-    <Pk as str::FromStr>::Err: ToString,
-    <<Pk as MiniscriptKey>::Hash as str::FromStr>::Err: ToString,
-{
-    type Err = Error;
-
+impl_from_str!(
+    Policy<Pk>,
+    type Err = Error;,
     fn from_str(s: &str) -> Result<Policy<Pk>, Error> {
         for ch in s.as_bytes() {
             if *ch < 20 || *ch > 127 {
@@ -700,22 +722,18 @@ where
         policy.check_timelocks()?;
         Ok(policy)
     }
-}
+);
 
 serde_string_impl_pk!(Policy, "a miniscript concrete policy");
 
-impl<Pk> Policy<Pk>
-where
-    Pk: MiniscriptKey + str::FromStr,
-    Pk::Hash: str::FromStr,
-    <Pk as str::FromStr>::Err: ToString,
-{
+#[rustfmt::skip]
+impl_block_str!(
+    Policy<Pk>,
     /// Helper function for `from_tree` to parse subexpressions with
     /// names of the form x@y
-    fn from_tree_prob(
-        top: &expression::Tree,
-        allow_prob: bool,
-    ) -> Result<(usize, Policy<Pk>), Error> {
+    fn from_tree_prob(top: &expression::Tree, allow_prob: bool,)
+        -> Result<(usize, Policy<Pk>), Error>
+    {
         let frag_prob;
         let frag_name;
         let mut name_split = top.name.split('@');
@@ -762,7 +780,7 @@ where
                 Ok(Policy::Older(num))
             }
             ("sha256", 1) => expression::terminal(&top.args[0], |x| {
-                sha256::Hash::from_hex(x).map(Policy::Sha256)
+                <Pk::Sha256 as core::str::FromStr>::from_str(x).map(Policy::Sha256)
             }),
             ("hash256", 1) => expression::terminal(&top.args[0], |x| {
                 sha256d::Hash::from_hex(x).map(Policy::Hash256)
@@ -813,18 +831,14 @@ where
         }
         .map(|res| (frag_prob, res))
     }
-}
+);
 
-impl<Pk> FromTree for Policy<Pk>
-where
-    Pk: MiniscriptKey + str::FromStr,
-    Pk::Hash: str::FromStr,
-    <Pk as str::FromStr>::Err: ToString,
-{
+impl_from_tree!(
+    Policy<Pk>,
     fn from_tree(top: &expression::Tree) -> Result<Policy<Pk>, Error> {
         Policy::from_tree_prob(top, false).map(|(_, result)| result)
     }
-}
+);
 
 /// Create a Huffman Tree from compiled [Miniscript] nodes
 #[cfg(feature = "compiler")]
diff --git a/src/policy/mod.rs b/src/policy/mod.rs
index 10ee3af61..29552da7b 100644
--- a/src/policy/mod.rs
+++ b/src/policy/mod.rs
@@ -128,7 +128,7 @@ impl<Pk: MiniscriptKey, Ctx: ScriptContext> Liftable<Pk> for Terminal<Pk, Ctx> {
             Terminal::PkH(ref pkh) => Semantic::KeyHash(pkh.clone()),
             Terminal::After(t) => Semantic::After(t),
             Terminal::Older(t) => Semantic::Older(t),
-            Terminal::Sha256(h) => Semantic::Sha256(h),
+            Terminal::Sha256(ref h) => Semantic::Sha256(h.clone()),
             Terminal::Hash256(h) => Semantic::Hash256(h),
             Terminal::Ripemd160(h) => Semantic::Ripemd160(h),
             Terminal::Hash160(h) => Semantic::Hash160(h),
@@ -203,7 +203,7 @@ impl<Pk: MiniscriptKey> Liftable<Pk> for Concrete<Pk> {
             Concrete::Key(ref pk) => Semantic::KeyHash(pk.to_pubkeyhash()),
             Concrete::After(t) => Semantic::After(t),
             Concrete::Older(t) => Semantic::Older(t),
-            Concrete::Sha256(h) => Semantic::Sha256(h),
+            Concrete::Sha256(ref h) => Semantic::Sha256(h.clone()),
             Concrete::Hash256(h) => Semantic::Hash256(h),
             Concrete::Ripemd160(h) => Semantic::Ripemd160(h),
             Concrete::Hash160(h) => Semantic::Hash160(h),
diff --git a/src/policy/semantic.rs b/src/policy/semantic.rs
index 83d60b172..58452429d 100644
--- a/src/policy/semantic.rs
+++ b/src/policy/semantic.rs
@@ -18,12 +18,12 @@ use core::str::FromStr;
 use core::{fmt, str};
 
 use bitcoin::hashes::hex::FromHex;
-use bitcoin::hashes::{hash160, ripemd160, sha256, sha256d};
+use bitcoin::hashes::{hash160, ripemd160, sha256d};
 
 use super::concrete::PolicyError;
 use super::ENTAILMENT_MAX_TERMINALS;
 use crate::prelude::*;
-use crate::{errstr, expression, timelock, Error, ForEach, ForEachKey, MiniscriptKey};
+use crate::{errstr, expression, timelock, Error, ForEach, ForEachKey, MiniscriptKey, Translator};
 
 /// Abstract policy which corresponds to the semantics of a Miniscript
 /// and which allows complex forms of analysis, e.g. filtering and
@@ -44,7 +44,7 @@ pub enum Policy<Pk: MiniscriptKey> {
     /// A relative locktime restriction
     Older(u32),
     /// A SHA256 whose preimage must be provided to satisfy the descriptor
-    Sha256(sha256::Hash),
+    Sha256(Pk::Sha256),
     /// A SHA256d whose preimage must be provided to satisfy the descriptor
     Hash256(sha256d::Hash),
     /// A RIPEMD160 whose preimage must be provided to satisfy the descriptor
@@ -82,39 +82,67 @@ impl<Pk: MiniscriptKey> Policy<Pk> {
     /// # Example
     ///
     /// ```
-    /// use miniscript::{bitcoin::{hashes::hash160, PublicKey}, policy::semantic::Policy};
+    /// use miniscript::{bitcoin::{hashes::hash160, PublicKey}, policy::semantic::Policy, Translator};
     /// use std::str::FromStr;
+    /// use std::collections::HashMap;
+    /// use miniscript::bitcoin::hashes::sha256;
     /// let alice_pkh = "236ada020df3208d2517f4b0db03e16f92cd8cf1";
     /// let bob_pkh = "3e89b972416ae33870b4634d03b8cdc773200cac";
     /// let placeholder_policy = Policy::<String>::from_str("and(pkh(alice_pkh),pkh(bob_pkh))").unwrap();
     ///
-    /// let real_policy = placeholder_policy.translate_pkh(|placeholder| match placeholder.as_str() {
-    ///     "alice_pkh" => hash160::Hash::from_str(alice_pkh),
-    ///     "bob_pkh"   => hash160::Hash::from_str(bob_pkh),
-    ///     _ => panic!("unknown key hash!")
-    /// }).unwrap();
+    /// // Information to translator abstract String type keys to concrete bitcoin::PublicKey.
+    /// // In practice, wallets would map from String key names to BIP32 keys
+    /// struct StrPkTranslator {
+    ///     pk_map: HashMap<String, hash160::Hash>
+    /// }
     ///
-    /// let expected_policy = Policy::<PublicKey>::from_str(&format!("and(pkh({}),pkh({}))", alice_pkh, bob_pkh)).unwrap();
+    /// // If we also wanted to provide mapping of other associated types(sha256, older etc),
+    /// // we would use the general Translator Trait.
+    /// impl Translator<String, bitcoin::PublicKey, ()> for StrPkTranslator {
+    ///     fn pk(&mut self, pk: &String) -> Result<bitcoin::PublicKey, ()> {
+    ///         unreachable!("Policy does not contain any pk fragment");
+    ///     }
+    ///
+    ///     // Provides the translation public keys P::Hash -> Q::Hash
+    ///     // If our policy also contained other fragments, we could provide the translation here.
+    ///     fn pkh(&mut self, pkh: &String) -> Result<hash160::Hash, ()> {
+    ///         self.pk_map.get(pkh).copied().ok_or(()) // Dummy Err
+    ///     }
+    ///
+    ///     // If our policy also contained other fragments, we could provide the translation here.
+    ///     fn sha256(&mut self, sha256: &String) -> Result<sha256::Hash, ()> {
+    ///         unreachable!("Policy does not contain any sha256 fragment");
+    ///     }
+    /// }
+    ///
+    /// let mut pk_map = HashMap::new();
+    /// pk_map.insert(String::from("alice_pkh"), hash160::Hash::from_str(alice_pkh).unwrap());
+    /// pk_map.insert(String::from("bob_pkh"), hash160::Hash::from_str(bob_pkh).unwrap());
+    /// let mut t = StrPkTranslator { pk_map: pk_map };
+    ///
+    /// let real_policy = placeholder_policy.translate_pkh(&mut t).unwrap();
+    ///
+    /// let expected_policy = Policy::from_str(&format!("and(pkh({}),pkh({}))", alice_pkh, bob_pkh)).unwrap();
     /// assert_eq!(real_policy, expected_policy);
     /// ```
-    pub fn translate_pkh<Fpkh, Q, E>(&self, mut fpkh: Fpkh) -> Result<Policy<Q>, E>
+    pub fn translate_pkh<Q, E, T>(&self, t: &mut T) -> Result<Policy<Q>, E>
     where
-        Fpkh: FnMut(&Pk::Hash) -> Result<Q::Hash, E>,
+        T: Translator<Pk, Q, E>,
         Q: MiniscriptKey,
     {
-        self._translate_pkh(&mut fpkh)
+        self._translate_pkh(t)
     }
 
-    fn _translate_pkh<Fpkh, Q, E>(&self, fpkh: &mut Fpkh) -> Result<Policy<Q>, E>
+    fn _translate_pkh<Q, E, T>(&self, t: &mut T) -> Result<Policy<Q>, E>
     where
-        Fpkh: FnMut(&Pk::Hash) -> Result<Q::Hash, E>,
+        T: Translator<Pk, Q, E>,
         Q: MiniscriptKey,
     {
         match *self {
             Policy::Unsatisfiable => Ok(Policy::Unsatisfiable),
             Policy::Trivial => Ok(Policy::Trivial),
-            Policy::KeyHash(ref pkh) => fpkh(pkh).map(Policy::KeyHash),
-            Policy::Sha256(ref h) => Ok(Policy::Sha256(*h)),
+            Policy::KeyHash(ref pkh) => t.pkh(pkh).map(Policy::KeyHash),
+            Policy::Sha256(ref h) => t.sha256(h).map(Policy::Sha256),
             Policy::Hash256(ref h) => Ok(Policy::Hash256(*h)),
             Policy::Ripemd160(ref h) => Ok(Policy::Ripemd160(*h)),
             Policy::Hash160(ref h) => Ok(Policy::Hash160(*h)),
@@ -122,7 +150,7 @@ impl<Pk: MiniscriptKey> Policy<Pk> {
             Policy::Older(n) => Ok(Policy::Older(n)),
             Policy::Threshold(k, ref subs) => {
                 let new_subs: Result<Vec<Policy<Q>>, _> =
-                    subs.iter().map(|sub| sub._translate_pkh(fpkh)).collect();
+                    subs.iter().map(|sub| sub._translate_pkh(t)).collect();
                 new_subs.map(|ok| Policy::Threshold(k, ok))
             }
         }
@@ -221,7 +249,7 @@ impl<Pk: MiniscriptKey> fmt::Debug for Policy<Pk> {
             Policy::KeyHash(ref pkh) => write!(f, "pkh({:?})", pkh),
             Policy::After(n) => write!(f, "after({})", n),
             Policy::Older(n) => write!(f, "older({})", n),
-            Policy::Sha256(h) => write!(f, "sha256({})", h),
+            Policy::Sha256(ref h) => write!(f, "sha256({})", h),
             Policy::Hash256(h) => write!(f, "hash256({})", h),
             Policy::Ripemd160(h) => write!(f, "ripemd160({})", h),
             Policy::Hash160(h) => write!(f, "hash160({})", h),
@@ -254,7 +282,7 @@ impl<Pk: MiniscriptKey> fmt::Display for Policy<Pk> {
             Policy::KeyHash(ref pkh) => write!(f, "pkh({})", pkh),
             Policy::After(n) => write!(f, "after({})", n),
             Policy::Older(n) => write!(f, "older({})", n),
-            Policy::Sha256(h) => write!(f, "sha256({})", h),
+            Policy::Sha256(ref h) => write!(f, "sha256({})", h),
             Policy::Hash256(h) => write!(f, "hash256({})", h),
             Policy::Ripemd160(h) => write!(f, "ripemd160({})", h),
             Policy::Hash160(h) => write!(f, "hash160({})", h),
@@ -279,15 +307,9 @@ impl<Pk: MiniscriptKey> fmt::Display for Policy<Pk> {
     }
 }
 
-impl<Pk> str::FromStr for Policy<Pk>
-where
-    Pk: MiniscriptKey + str::FromStr,
-    Pk::Hash: str::FromStr,
-    <Pk as str::FromStr>::Err: ToString,
-    <<Pk as MiniscriptKey>::Hash as str::FromStr>::Err: ToString,
-{
-    type Err = Error;
-
+impl_from_str!(
+    Policy<Pk>,
+    type Err = Error;,
     fn from_str(s: &str) -> Result<Policy<Pk>, Error> {
         for ch in s.as_bytes() {
             if *ch < 20 || *ch > 127 {
@@ -298,17 +320,12 @@ where
         let tree = expression::Tree::from_str(s)?;
         expression::FromTree::from_tree(&tree)
     }
-}
+);
 
 serde_string_impl_pk!(Policy, "a miniscript semantic policy");
 
-impl<Pk> expression::FromTree for Policy<Pk>
-where
-    Pk: MiniscriptKey + str::FromStr,
-    Pk::Hash: str::FromStr,
-    <Pk as str::FromStr>::Err: ToString,
-    <<Pk as MiniscriptKey>::Hash as str::FromStr>::Err: ToString,
-{
+impl_from_tree!(
+    Policy<Pk>,
     fn from_tree(top: &expression::Tree) -> Result<Policy<Pk>, Error> {
         match (top.name, top.args.len()) {
             ("UNSATISFIABLE", 0) => Ok(Policy::Unsatisfiable),
@@ -323,7 +340,7 @@ where
                 expression::parse_num(x).map(Policy::Older)
             }),
             ("sha256", 1) => expression::terminal(&top.args[0], |x| {
-                sha256::Hash::from_hex(x).map(Policy::Sha256)
+                Pk::Sha256::from_str(x).map(Policy::Sha256)
             }),
             ("hash256", 1) => expression::terminal(&top.args[0], |x| {
                 sha256d::Hash::from_hex(x).map(Policy::Hash256)
@@ -384,7 +401,7 @@ where
             _ => Err(errstr(top.name)),
         }
     }
-}
+);
 
 impl<Pk: MiniscriptKey> Policy<Pk> {
     /// Flatten out trees of `And`s and `Or`s; eliminate `Trivial` and
diff --git a/src/psbt/mod.rs b/src/psbt/mod.rs
index 0a78ef6e2..cc8a9f7c1 100644
--- a/src/psbt/mod.rs
+++ b/src/psbt/mod.rs
@@ -24,8 +24,8 @@ use core::ops::Deref;
 #[cfg(feature = "std")]
 use std::error;
 
-use bitcoin::hashes::{hash160, ripemd160, sha256, sha256d};
-use bitcoin::secp256k1::{self, Secp256k1};
+use bitcoin::hashes::{hash160, ripemd160, sha256d};
+use bitcoin::secp256k1::{self, Secp256k1, VerifyOnly};
 use bitcoin::util::psbt::{self, PartiallySignedTransaction as Psbt};
 use bitcoin::util::sighash::SighashCache;
 use bitcoin::util::taproot::{self, ControlBlock, LeafVersion, TapLeafHash};
@@ -36,8 +36,8 @@ use crate::miniscript::limits::SEQUENCE_LOCKTIME_DISABLE_FLAG;
 use crate::miniscript::satisfy::{After, Older};
 use crate::prelude::*;
 use crate::{
-    descriptor, interpreter, Descriptor, DescriptorPublicKey, MiniscriptKey, Preimage32, Satisfier,
-    ToPublicKey, TranslatePk, TranslatePk2,
+    descriptor, interpreter, Descriptor, DescriptorPublicKey, MiniscriptKey, PkTranslator,
+    Preimage32, Satisfier, ToPublicKey, TranslatePk,
 };
 
 mod finalizer;
@@ -238,9 +238,7 @@ impl fmt::Display for InputError {
                  sighashflag {:?} rather than required {:?}",
                 pubkey, got, required
             ),
-            InputError::CouldNotSatisfyTr => {
-                write!(f, "Could not satisfy Tr descriptor")
-            }
+            InputError::CouldNotSatisfyTr => write!(f, "Could not satisfy Tr descriptor"),
             InputError::NonStandardSighashType(e) => write!(f, "Non-standard sighash type {}", e),
         }
     }
@@ -370,10 +368,10 @@ impl<'psbt, Pk: MiniscriptKey + ToPublicKey> Satisfier<Pk> for PsbtInputSatisfie
             .and_then(try_vec_as_preimage32)
     }
 
-    fn lookup_sha256(&self, h: sha256::Hash) -> Option<Preimage32> {
+    fn lookup_sha256(&self, h: &Pk::Sha256) -> Option<Preimage32> {
         self.psbt.inputs[self.index]
             .sha256_preimages
-            .get(&h)
+            .get(&Pk::to_sha256(h))
             .and_then(try_vec_as_preimage32)
     }
 
@@ -932,6 +930,65 @@ impl PsbtInputExt for psbt::Input {
     }
 }
 
+// Traverse the pkh lookup while maintaining a reverse map for storing the map
+// hash160 -> (XonlyPublicKey)/PublicKey
+struct XOnlyHashLookUp(
+    pub BTreeMap<hash160::Hash, bitcoin::XOnlyPublicKey>,
+    pub secp256k1::Secp256k1<VerifyOnly>,
+);
+
+impl PkTranslator<DescriptorPublicKey, bitcoin::PublicKey, descriptor::ConversionError>
+    for XOnlyHashLookUp
+{
+    fn pk(
+        &mut self,
+        xpk: &DescriptorPublicKey,
+    ) -> Result<bitcoin::PublicKey, descriptor::ConversionError> {
+        xpk.derive_public_key(&self.1)
+    }
+
+    fn pkh(
+        &mut self,
+        xpk: &DescriptorPublicKey,
+    ) -> Result<hash160::Hash, descriptor::ConversionError> {
+        let pk = xpk.derive_public_key(&self.1)?;
+        let xonly = pk.to_x_only_pubkey();
+        let hash = xonly.to_pubkeyhash();
+        self.0.insert(hash, xonly);
+        Ok(hash)
+    }
+}
+
+// Traverse the pkh lookup while maintaining a reverse map for storing the map
+// hash160 -> (XonlyPublicKey)/PublicKey
+struct KeySourceLookUp(
+    pub BTreeMap<secp256k1::PublicKey, bitcoin::util::bip32::KeySource>,
+    pub secp256k1::Secp256k1<VerifyOnly>,
+);
+
+impl PkTranslator<DescriptorPublicKey, bitcoin::PublicKey, descriptor::ConversionError>
+    for KeySourceLookUp
+{
+    fn pk(
+        &mut self,
+        xpk: &DescriptorPublicKey,
+    ) -> Result<bitcoin::PublicKey, descriptor::ConversionError> {
+        let derived = xpk.derive_public_key(&self.1)?;
+        self.0.insert(
+            derived.to_public_key().inner,
+            (xpk.master_fingerprint(), xpk.full_derivation_path()),
+        );
+        Ok(derived)
+    }
+
+    fn pkh(
+        &mut self,
+        xpk: &DescriptorPublicKey,
+    ) -> Result<hash160::Hash, descriptor::ConversionError> {
+        Ok(self.pk(xpk)?.to_pubkeyhash())
+    }
+}
+
 fn update_input_with_descriptor_helper(
     input: &mut psbt::Input,
     descriptor: &Descriptor<DescriptorPublicKey>,
@@ -940,20 +997,12 @@ fn update_input_with_descriptor_helper(
     // One needs the derived descriptor and the other needs to know whether the script_pubkey check
     // failed.
 ) -> Result<(Descriptor<bitcoin::PublicKey>, bool), descriptor::ConversionError> {
-    use core::cell::RefCell;
     let secp = secp256k1::Secp256k1::verification_only();
 
     let derived = if let Descriptor::Tr(_) = &descriptor {
-        let mut hash_lookup = BTreeMap::new();
-        let derived = descriptor.translate_pk(
-            |xpk| xpk.derive_public_key(&secp),
-            |xpk| {
-                let xonly = xpk.derive_public_key(&secp)?.to_x_only_pubkey();
-                let hash = xonly.to_pubkeyhash();
-                hash_lookup.insert(hash, xonly);
-                Ok(hash)
-            },
-        )?;
+        let mut hash_lookup = XOnlyHashLookUp(BTreeMap::new(), secp);
+        // Feed in information about pkh -> pk mapping here
+        let derived = descriptor.translate_pk(&mut hash_lookup)?;
 
         if let Some(check_script) = check_script {
             if check_script != derived.script_pubkey() {
@@ -994,6 +1043,7 @@ fn update_input_with_descriptor_helper(
                         }
                         (PkPkh::HashedPubkey(hash), PkPkh::HashedPubkey(xpk)) => (
                             *hash_lookup
+                                .0
                                 .get(&hash)
                                 .expect("translate_pk inserted an entry for every hash"),
                             xpk,
@@ -1022,15 +1072,8 @@ fn update_input_with_descriptor_helper(
         derived
     } else {
         // have to use a RefCell because we can't pass FnMut to translate_pk2
-        let bip32_derivation = RefCell::new(BTreeMap::new());
-        let derived = descriptor.translate_pk2(|xpk| {
-            let derived = xpk.derive_public_key(&secp)?;
-            bip32_derivation.borrow_mut().insert(
-                derived.to_public_key().inner,
-                (xpk.master_fingerprint(), xpk.full_derivation_path()),
-            );
-            Ok(derived)
-        })?;
+        let mut bip32_derivation = KeySourceLookUp(BTreeMap::new(), Secp256k1::verification_only());
+        let derived = descriptor.translate_pk(&mut bip32_derivation)?;
 
         if let Some(check_script) = check_script {
             if check_script != derived.script_pubkey() {
@@ -1038,7 +1081,7 @@ fn update_input_with_descriptor_helper(
             }
         }
 
-        input.bip32_derivation = bip32_derivation.into_inner();
+        input.bip32_derivation = bip32_derivation.0;
 
         match &derived {
             Descriptor::Bare(_) | Descriptor::Pkh(_) | Descriptor::Wpkh(_) => {}
diff --git a/src/test_utils.rs b/src/test_utils.rs
new file mode 100644
index 000000000..8098482b4
--- /dev/null
+++ b/src/test_utils.rs
@@ -0,0 +1,150 @@
+//! Generally useful utilities for test scripts
+
+use std::collections::HashMap;
+use std::str::FromStr;
+
+use bitcoin::hashes::{hash160, sha256};
+use bitcoin::secp256k1;
+
+use crate::{MiniscriptKey, Translator};
+
+/// Translate from a String MiniscriptKey type to bitcoin::PublicKey
+/// If the hashmap is populated, this will lookup for keys in HashMap
+/// Otherwise, this will return a translation to a random key
+#[derive(Debug, PartialEq, Eq, Clone)]
+pub struct StrKeyTranslator {
+    pub pk_map: HashMap<String, bitcoin::PublicKey>,
+    pub pkh_map: HashMap<String, hash160::Hash>,
+    pub sha256_map: HashMap<String, sha256::Hash>,
+}
+
+impl Translator<String, bitcoin::PublicKey, ()> for StrKeyTranslator {
+    fn pk(&mut self, pk: &String) -> Result<bitcoin::PublicKey, ()> {
+        let key = self.pk_map.get(pk).copied().unwrap_or_else(|| {
+            bitcoin::PublicKey::from_str(
+                "02c2122e30e73f7fe37986e3f81ded00158e94b7ad472369b83bbdd28a9a198a39",
+            )
+            .unwrap()
+        });
+        Ok(key)
+    }
+
+    fn pkh(&mut self, pkh: &String) -> Result<hash160::Hash, ()> {
+        let hash = self.pkh_map.get(pkh).copied().unwrap_or_else(|| {
+            hash160::Hash::from_str("be8f27af36217ba89c793c419f058cd4e2a54e26").unwrap()
+        });
+        Ok(hash)
+    }
+
+    fn sha256(&mut self, _sha256: &String) -> Result<sha256::Hash, ()> {
+        let hash = sha256::Hash::from_str(
+            "4ae81572f06e1b88fd5ced7a1a000945432e83e1551e6f721ee9c00b8cc33260",
+        )
+        .unwrap();
+        Ok(hash)
+    }
+}
+
+/// Same as [`StrKeyTranslator`], but for [`bitcoin::XOnlyPublicKey`]
+#[derive(Debug, PartialEq, Eq, Clone)]
+pub struct StrXOnlyKeyTranslator {
+    pub pk_map: HashMap<String, bitcoin::XOnlyPublicKey>,
+    pub pkh_map: HashMap<String, hash160::Hash>,
+    pub sha256_map: HashMap<String, sha256::Hash>,
+}
+
+impl Translator<String, bitcoin::XOnlyPublicKey, ()> for StrXOnlyKeyTranslator {
+    fn pk(&mut self, pk: &String) -> Result<bitcoin::XOnlyPublicKey, ()> {
+        let key = self.pk_map.get(pk).copied().unwrap_or_else(|| {
+            bitcoin::XOnlyPublicKey::from_str(
+                "c2122e30e73f7fe37986e3f81ded00158e94b7ad472369b83bbdd28a9a198a39",
+            )
+            .unwrap()
+        });
+        Ok(key)
+    }
+
+    fn pkh(&mut self, pkh: &String) -> Result<hash160::Hash, ()> {
+        let hash = self.pkh_map.get(pkh).copied().unwrap_or_else(|| {
+            hash160::Hash::from_str("be8f27af36217ba89c793c419f058cd4e2a54e26").unwrap()
+        });
+        Ok(hash)
+    }
+
+    fn sha256(&mut self, _sha256: &String) -> Result<sha256::Hash, ()> {
+        let hash = sha256::Hash::from_str(
+            "4ae81572f06e1b88fd5ced7a1a000945432e83e1551e6f721ee9c00b8cc33260",
+        )
+        .unwrap();
+        Ok(hash)
+    }
+}
+
+// Deterministically sample keys to allow reproducible tests
+fn random_sks(n: usize) -> Vec<secp256k1::SecretKey> {
+    let mut sk = [0; 32];
+    let mut sks = vec![];
+    for i in 1..n + 1 {
+        sk[0] = i as u8;
+        sk[1] = (i >> 8) as u8;
+        sk[2] = (i >> 16) as u8;
+        sk[3] = (i >> 24) as u8;
+
+        let sk = secp256k1::SecretKey::from_slice(&sk[..]).expect("secret key");
+        sks.push(sk)
+    }
+    sks
+}
+
+impl StrKeyTranslator {
+    pub fn new() -> Self {
+        let secp = secp256k1::Secp256k1::new();
+        let sks = random_sks(26);
+        let pks: Vec<_> = sks
+            .iter()
+            .map(|sk| bitcoin::PublicKey::new(secp256k1::PublicKey::from_secret_key(&secp, sk)))
+            .collect();
+        let mut pk_map = HashMap::new();
+        let mut pkh_map = HashMap::new();
+        for (i, c) in (b'A'..b'Z').enumerate() {
+            let key = String::from_utf8(vec![c]).unwrap();
+            pk_map.insert(key.clone(), pks[i]);
+            pkh_map.insert(key, pks[i].to_pubkeyhash());
+        }
+        // We don't bother filling in sha256_map preimages in default implementation as it not unnecessary
+        // for sane miniscripts
+        Self {
+            pk_map,
+            pkh_map,
+            sha256_map: HashMap::new(),
+        }
+    }
+}
+
+impl StrXOnlyKeyTranslator {
+    pub fn new() -> Self {
+        let secp = secp256k1::Secp256k1::new();
+        let sks = random_sks(26);
+        let pks: Vec<_> = sks
+            .iter()
+            .map(|sk| {
+                let keypair = secp256k1::KeyPair::from_secret_key(&secp, *sk);
+                bitcoin::XOnlyPublicKey::from_keypair(&keypair)
+            })
+            .collect();
+        let mut pk_map = HashMap::new();
+        let mut pkh_map = HashMap::new();
+        for (i, c) in (b'A'..b'Z').enumerate() {
+            let key = String::from_utf8(vec![c]).unwrap();
+            pk_map.insert(key.clone(), pks[i]);
+            pkh_map.insert(key, pks[i].to_pubkeyhash());
+        }
+        // We don't bother filling in sha256_map preimages in default implementation as it not unnecessary
+        // for sane miniscripts
+        Self {
+            pk_map,
+            pkh_map,
+            sha256_map: HashMap::new(),
+        }
+    }
+}
diff --git a/tests/setup/test_util.rs b/tests/setup/test_util.rs
index 019b7c179..820d5c811 100644
--- a/tests/setup/test_util.rs
+++ b/tests/setup/test_util.rs
@@ -24,7 +24,9 @@ use bitcoin::hashes::hex::ToHex;
 use bitcoin::hashes::{hash160, ripemd160, sha256, sha256d, Hash};
 use bitcoin::secp256k1;
 use miniscript::descriptor::{SinglePub, SinglePubKey};
-use miniscript::{Descriptor, DescriptorPublicKey, Miniscript, ScriptContext, TranslatePk};
+use miniscript::{
+    Descriptor, DescriptorPublicKey, Miniscript, ScriptContext, TranslatePk, Translator,
+};
 use rand::RngCore;
 
 #[derive(Clone, Debug)]
@@ -153,127 +155,105 @@ pub fn parse_insane_ms<Ctx: ScriptContext>(
     let ms = subs_hash_frag(ms, pubdata);
     let ms =
         Miniscript::<String, Ctx>::from_str_insane(&ms).expect("only parsing valid minsicripts");
-    let mut i = 0;
-    let mut j = pubdata.pks.len();
-    let ms = ms.translate_pk_infallible(
-        &mut |pk_str: &String| {
-            let avail = !pk_str.ends_with("!");
-            if avail {
-                i = i + 1;
-                if pk_str.starts_with("K") {
-                    DescriptorPublicKey::Single(SinglePub {
-                        origin: None,
-                        key: SinglePubKey::FullKey(pubdata.pks[i]),
-                    })
-                } else if pk_str.starts_with("X") {
-                    DescriptorPublicKey::Single(SinglePub {
-                        origin: None,
-                        key: SinglePubKey::XOnly(pubdata.x_only_pks[i]),
-                    })
-                } else {
-                    // Parse any other keys as known to allow compatibility with existing tests
-                    DescriptorPublicKey::Single(SinglePub {
-                        origin: None,
-                        key: SinglePubKey::FullKey(pubdata.pks[i]),
-                    })
-                }
-            } else {
-                DescriptorPublicKey::Single(SinglePub {
+    let mut translator = StrTranslatorLoose(0, pubdata);
+    let ms = ms.translate_pk(&mut translator).unwrap();
+    ms
+}
+
+// Translate Str to DescriptorPublicKey
+#[derive(Debug, Clone)]
+struct StrDescPubKeyTranslator<'a>(usize, &'a PubData);
+
+impl<'a> Translator<String, DescriptorPublicKey, ()> for StrDescPubKeyTranslator<'a> {
+    fn pk(&mut self, pk_str: &String) -> Result<DescriptorPublicKey, ()> {
+        let avail = !pk_str.ends_with("!");
+        if avail {
+            self.0 = self.0 + 1;
+            if pk_str.starts_with("K") {
+                Ok(DescriptorPublicKey::Single(SinglePub {
                     origin: None,
-                    key: SinglePubKey::FullKey(random_pk(59)),
-                })
-            }
-        },
-        &mut |pk_str: &String| {
-            let avail = !pk_str.ends_with("!");
-            if avail {
-                j = j - 1;
-                if pk_str.starts_with("K") {
-                    DescriptorPublicKey::Single(SinglePub {
-                        origin: None,
-                        key: SinglePubKey::FullKey(pubdata.pks[j]),
-                    })
-                } else if pk_str.starts_with("X") {
-                    DescriptorPublicKey::Single(SinglePub {
-                        origin: None,
-                        key: SinglePubKey::XOnly(pubdata.x_only_pks[j]),
-                    })
-                } else {
-                    // Parse any other keys as known to allow compatibility with existing tests
-                    DescriptorPublicKey::Single(SinglePub {
-                        origin: None,
-                        key: SinglePubKey::FullKey(pubdata.pks[j]),
-                    })
-                }
-            } else {
-                DescriptorPublicKey::Single(SinglePub {
+                    key: SinglePubKey::FullKey(self.1.pks[self.0]),
+                }))
+            } else if pk_str.starts_with("X") {
+                Ok(DescriptorPublicKey::Single(SinglePub {
                     origin: None,
-                    key: SinglePubKey::FullKey(random_pk(59)),
-                })
+                    key: SinglePubKey::XOnly(self.1.x_only_pks[self.0]),
+                }))
+            } else {
+                panic!("Key must start with either K or X")
             }
-        },
-    );
-    ms
+        } else {
+            Ok(DescriptorPublicKey::Single(SinglePub {
+                origin: None,
+                key: SinglePubKey::FullKey(random_pk(59)),
+            }))
+        }
+    }
+
+    fn pkh(&mut self, pkh: &String) -> Result<DescriptorPublicKey, ()> {
+        self.pk(pkh)
+    }
+
+    fn sha256(&mut self, sha256: &String) -> Result<sha256::Hash, ()> {
+        let sha = sha256::Hash::from_str(sha256).unwrap();
+        Ok(sha)
+    }
 }
 
-#[allow(dead_code)]
-// https://github.com/rust-lang/rust/issues/46379. The code is pub fn and integration test, but still shows warnings
-pub fn parse_test_desc(desc: &str, pubdata: &PubData) -> Descriptor<DescriptorPublicKey> {
-    let desc = subs_hash_frag(desc, pubdata);
-    let desc =
-        Descriptor::<String>::from_str(&desc).expect("only parsing valid and sane descriptors");
-    let mut i = 0;
-    let mut j = pubdata.pks.len();
-    let desc: Result<_, ()> = desc.translate_pk(
-        &mut |pk_str: &'_ String| {
-            let avail = !pk_str.ends_with("!");
-            if avail {
-                i = i + 1;
-                if pk_str.starts_with("K") {
-                    Ok(DescriptorPublicKey::Single(SinglePub {
-                        origin: None,
-                        key: SinglePubKey::FullKey(pubdata.pks[i]),
-                    }))
-                } else if pk_str.starts_with("X") {
-                    Ok(DescriptorPublicKey::Single(SinglePub {
-                        origin: None,
-                        key: SinglePubKey::XOnly(pubdata.x_only_pks[i]),
-                    }))
-                } else {
-                    panic!("Key must start with either K or X")
-                }
-            } else {
+// Translate Str to DescriptorPublicKey
+// Same as StrDescPubKeyTranslator, but does not panic when Key is not starting with
+// K or X. This is used when testing vectors from C++ to rust
+#[derive(Debug, Clone)]
+struct StrTranslatorLoose<'a>(usize, &'a PubData);
+
+impl<'a> Translator<String, DescriptorPublicKey, ()> for StrTranslatorLoose<'a> {
+    fn pk(&mut self, pk_str: &String) -> Result<DescriptorPublicKey, ()> {
+        let avail = !pk_str.ends_with("!");
+        if avail {
+            self.0 = self.0 + 1;
+            if pk_str.starts_with("K") {
                 Ok(DescriptorPublicKey::Single(SinglePub {
                     origin: None,
-                    key: SinglePubKey::FullKey(random_pk(59)),
+                    key: SinglePubKey::FullKey(self.1.pks[self.0]),
+                }))
+            } else if pk_str.starts_with("X") {
+                Ok(DescriptorPublicKey::Single(SinglePub {
+                    origin: None,
+                    key: SinglePubKey::XOnly(self.1.x_only_pks[self.0]),
                 }))
-            }
-        },
-        &mut |pkh_str: &'_ String| {
-            let avail = !pkh_str.ends_with("!");
-            if avail {
-                j = j - 1;
-                if pkh_str.starts_with("K") {
-                    Ok(DescriptorPublicKey::Single(SinglePub {
-                        origin: None,
-                        key: SinglePubKey::FullKey(pubdata.pks[j]),
-                    }))
-                } else if pkh_str.starts_with("X") {
-                    Ok(DescriptorPublicKey::Single(SinglePub {
-                        origin: None,
-                        key: SinglePubKey::XOnly(pubdata.x_only_pks[j]),
-                    }))
-                } else {
-                    panic!("Key must start with either K or X")
-                }
             } else {
+                // Parse any other keys as known to allow compatibility with existing tests
                 Ok(DescriptorPublicKey::Single(SinglePub {
                     origin: None,
-                    key: SinglePubKey::FullKey(random_pk(61)),
+                    key: SinglePubKey::FullKey(self.1.pks[self.0]),
                 }))
             }
-        },
-    );
+        } else {
+            Ok(DescriptorPublicKey::Single(SinglePub {
+                origin: None,
+                key: SinglePubKey::FullKey(random_pk(59)),
+            }))
+        }
+    }
+
+    fn pkh(&mut self, pkh: &String) -> Result<DescriptorPublicKey, ()> {
+        self.pk(pkh)
+    }
+
+    fn sha256(&mut self, sha256: &String) -> Result<sha256::Hash, ()> {
+        let sha = sha256::Hash::from_str(sha256).unwrap();
+        Ok(sha)
+    }
+}
+
+#[allow(dead_code)]
+// https://github.com/rust-lang/rust/issues/46379. The code is pub fn and integration test, but still shows warnings
+pub fn parse_test_desc(desc: &str, pubdata: &PubData) -> Descriptor<DescriptorPublicKey> {
+    let desc = subs_hash_frag(desc, pubdata);
+    let desc =
+        Descriptor::<String>::from_str(&desc).expect("only parsing valid and sane descriptors");
+    let mut translator = StrDescPubKeyTranslator(0, pubdata);
+    let desc: Result<_, ()> = desc.translate_pk(&mut translator);
     desc.expect("Translate must succeed")
 }