Mustache specs - lambda compliance

[danielfagerstrom]

Fixed most of the failing lambda tests from the Mustache spec from my Mustache spec pull request.

The spec says that for a function that is returned in a section or an interpolation:

1. When used as the data value for an Interpolation tag, the lambda MUST be
   treatable as an arity 0 function, and invoked as such. The returned value
   MUST be rendered against the default delimiters, then interpolated in place
   of the lambda.
2. When used as the data value for a Section tag, the lambda MUST be treatable
   as an arity 1 function, and invoked as such (passing a String containing the
   unprocessed section contents). The returned value MUST be rendered against
   the current delimiters, then interpolated in place of the section.

In current mustache.js the return value from a function in a interpolation or section is not interpolated so I implemented that.

For the section functions this breaks one of the current tests so I updated that one.

The test for "Section - Alternate Delimiters - Lambdas used for sections should parse with the current delimiters." still fails, I couldn't find any reasonably simple way to fix that.

[mjackson]

@danielfagerstrom I've merged the first few commits of this pull request already. Would you please rework this request to only include the last two commits (i.e. the ones that have to do with lambda compliance)? Thanks!

[eliOcs]

In version 0.7.2 lambdas don't work:

var Mustache = require("mustache");

Mustache.render("{{#lambda}}Hello{{/lambda}}", {
    lambda: function (hello) {
        return hello + " world!"
    }
}):

returns:

"Hello"

Expected

"Hello world!"

Are they going to be included soon?

[busticated]

hmm... perhaps related?.. i tried doing exactly this --> mustache/spec#54 (comment)

specifically:

view model:

{
    items: [
        { url: 'Some URL',      html: function() { return '{{>image}}'; } },
        { content: 'Some text', html: function() { return '{{>text}}'; } },
    ]
}

base.mustache

{{#items}}
    {{{html}}}
{{/items}}

text.mustache

<p>{{content}}</p>

image.mustache

<p><img src="{{url}}"/></p>

expected output:

<p><img src="Some URL"/></p>
<p>Some text</p>

actual output:

{{>image}} {{>text}}

JSFiddle Example

[andrewnicols]

I've encountered this recently. What's the current state of play if I were to take on the remaining changes?

Relevant part of the spec: https://github.com/mustache/spec/blob/master/specs/~lambdas.yml#L29

[MiniHeyd]

Is there any update on this? I am still seeing this issue with lambda's where {{ >second }} is printing Instead of the partial it is supposed to render.