Re-work the Pattern Parameter algorithm

[bmuenzenmeyer]

Async work has exposed what I believe to be a flaw in my pattern parameter algorithm.

Consider the following set of patterns:

paramParent.mustache

{{> test-paramMiddle(class: "foo") }}

paramParent.json

{
  "url" : "link.test-foo"
}

paramMiddle.mustache

<div class="{{class}}">
  {{> test-link }}
</div>

link.mustache

<a href="{{url}}">Click Here for Foo Pattern</a>

Expected Outcome

<div class="foo">
   <a href="../../patterns/test-foo/test-foo.rendered.html">Click Here for Foo Pattern</a>
</div>

Actual Outcome

<div class="foo">
</div>

Analysis

After troubleshooting for a while, I've called into question my decision to consume (i.e. immediately render) patterns when a pattern parameter is present. With async rendering within loops and recursion, this is just a nightmare.

What I am now pivoting to is a replacement of values only.

So we see class patternParameter, we replace the paramMiddle partial to:

<div class="foo">
  {{> test-link }}
</div>

and then carry on with additional resolution. I think this will yield results more consistent with user' expectations.

[bmuenzenmeyer]

Making good progress on this over on https://github.com/pattern-lab/patternlab-node/tree/pattern-param-rework