JSON Pretty printing

Author: mikera

convex-core/src/main/java/convex/core/util/JSONUtils.java

@@ -171,6 +171,18 @@ public static AString toJSONString(Object value) {
 		appendJSON(bb, value);
 		return Strings.create(bb.toBlob());
 	}
+	
+	/**
+	 * Convert any object to JSON
+	 * 
+	 * @param value Value to convert to JSON, may be Java or CVM structure
+	 * @return CVM String containing valid JSON
+	 */
+	public static AString toJSONPretty(Object value) {
+		BlobBuilder bb = new BlobBuilder();
+		appendPrettyJSON(bb, RT.cvm(value),0);
+		return Strings.create(bb.toBlob());
+	}
 
 	private static void appendJSON(BlobBuilder bb, Object value) {
 		if (value == null) {
@@ -336,6 +348,80 @@ private static void appendJSON(BlobBuilder bb, ACell value) {
 
 		throw new IllegalArgumentException("Can't print as JSON: "+Utils.getClassName(value));
 	}
+	
+	private static final int INDENT=2;
+	
+    private static BlobBuilder appendPrettyJSON(BlobBuilder sb, ACell o, int indent) {
+        if (o instanceof AMap) {
+            int entryIndent = indent + INDENT;
+            sb.append("{\n");
+            AMap<?, ?> m = ((AMap<?, ?>) o);
+            int size = m.size();
+            int pos = 0;
+            for (int i = 0; i < size; i++) {
+            	MapEntry<?,?> me=m.entryAt(i);
+                AString k = keyValue(me.getKey());
+                appendWhitespaceString(sb, entryIndent);
+                sb.append(toString(k));
+                sb.append(": ");
+                int vIndent = entryIndent + k.size() + 4; // indent for value
+                ACell v = me.getValue();
+                appendPrettyJSON(sb, v, vIndent);
+                pos++;
+                if (pos == size) {
+                    sb.append('\n'); // final entry
+                } else {
+                    sb.append(",\n"); // comma for next entry
+                }
+            }
+            appendWhitespaceString(sb, indent);
+            sb.append("}");
+        } else if (o instanceof ASequence) {
+        	ASequence<?> list = (ASequence<?>) o;
+            int size = list.size();
+            int entryIndent = indent + 1;
+            sb.append("[");
+            for (int i = 0; i < size; i++) {
+                if (i > 0) {
+                    sb.append(",\n");
+                    appendWhitespaceString(sb, entryIndent);
+                }
+                ACell v = list.get(i);
+                appendPrettyJSON(sb, v, entryIndent);
+            }
+            sb.append("]");
+        } else {
+            sb.append(toString(o));
+        }
+        return sb;
+    }
+    
+    /**
+     * Convert any CVM value into a JSON style key
+     * @param key
+     * @return
+     */
+    private static AString keyValue(ACell key) {
+		return RT.str(key);
+	}
+
+	private static final StringShort WHITESPACE=StringShort.create("                                ");
+    private static final long WHITESPACE_LENGTH=WHITESPACE.count();
+    /**
+     * Appends a whitespace string of the specified length.
+     *
+     * @param sb    StringBuilder to append the whitespace characters
+     * @param count Number of whitespace characters
+     * @return Updated StringBuilder
+     */
+    private static BlobBuilder appendWhitespaceString(BlobBuilder sb, long count) {
+        while (count > WHITESPACE_LENGTH) {
+            sb.append(WHITESPACE);
+            count -= WHITESPACE_LENGTH;
+        }
+        sb.append(WHITESPACE.slice(0, count));
+        return sb;
+    }
 
 
 	private static void appendCVMStringQuoted(BlobBuilder bb, CharSequence cs) {

convex-core/src/main/java/convex/core/util/Utils.java

@@ -1324,7 +1324,7 @@ public static String joinStrings(List<String> strings, String separator) {
 	 * @param c Divisor
 	 * @return Result of (a*b)/c
 	 */
-	static long slowMulDiv(long a, long b, long c) {
+	public static long slowMulDiv(long a, long b, long c) {
 		// TODO: we want a faster version of this
 
 		BigInteger result=BigInteger.valueOf(a).multiply(BigInteger.valueOf(b)).divide(BigInteger.valueOf(c));

convex-core/src/test/java/convex/core/data/VectorsTest.java

@@ -20,7 +20,7 @@
 import convex.core.data.util.VectorBuilder;
 import convex.core.exceptions.BadFormatException;
 import convex.core.lang.RT;
-import convex.core.utils.VisitCounter;
+import convex.core.util.VisitCounter;
 import convex.test.Samples;
 
 /**

convex-core/src/test/java/convex/core/util/EconomicsTest.java

@@ -9,6 +9,8 @@
 
 import org.junit.jupiter.api.Test;
 
+import convex.core.util.Economics;
+
 public class EconomicsTest {
 
 	@Test

convex-core/src/test/java/convex/core/util/GenTestEconomics.java

@@ -10,6 +10,9 @@
 import com.pholser.junit.quickcheck.Property;
 import com.pholser.junit.quickcheck.runner.JUnitQuickcheck;
 
+import convex.core.util.Economics;
+import convex.core.util.Utils;
+
 @RunWith(JUnitQuickcheck.class)
 public class GenTestEconomics {
 

convex-core/src/test/java/convex/core/utils/JSONUtilsTest.java renamed to convex-core/src/test/java/convex/core/util/JSONUtilsTest.java

@@ -1,4 +1,4 @@
-package convex.core.utils;
+package convex.core.util;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertNull;
@@ -34,7 +34,6 @@
 import convex.core.exceptions.ParseException;
 import convex.core.json.JSONReader;
 import convex.core.lang.RT;
-import convex.core.util.JSONUtils;
 
 public class JSONUtilsTest {
 
@@ -121,6 +120,11 @@ public void testEscape() {
 		assertEquals(StringShort.create(" \\\""),JSONUtils.escape(" \""));
 	}
 
+	@Test
+	public void testPrettyJSON() {
+		assertEquals("{\n  \"foo\": \"bar\"\n}",JSONUtils.toJSONPretty(Maps.of("foo","bar")).toString());
+	}
+	
 	@Test
 	public void testJSON() {
 		assertNull(JSONUtils.json(null));
@@ -226,6 +230,8 @@ private void checkJSON5Only(String s) {
 		JSONUtils.parseJSON5(s);
 	}
 
+
+	
 	@Test
 	public void testJSONRoundTrips() {
 
@@ -259,10 +265,13 @@ private void doJSONRoundTrip(Object o, ACell c) {
 		String js1=JSONUtils.toString(o);
 		String js2=JSONUtils.toString(c);
 		assertEquals(js1.length(),js2.length()); // should be same length, orders might differ
-		
+
+		String jsp=JSONUtils.toJSONPretty(c).toString();
+
 		// Written JSON should be parseable as strict JSON
 		assertEquals(c,JSONUtils.parse(js1),()->"JSON="+js1);
 		assertEquals(c,JSONUtils.parse(js2));
+		assertEquals(c,JSONUtils.parse(jsp));
 		assertEquals(c,JSONReader.read(js2));
 	}
 

convex-core/src/test/java/convex/core/utils/VisitCounter.java renamed to convex-core/src/test/java/convex/core/util/VisitCounter.java

@@ -1,4 +1,4 @@
-package convex.core.utils;
+package convex.core.util;
 
 import java.util.function.Consumer;