Clean up code in engine_twig and move to the correct location

Author: geoffp

builder/pattern_engines/engine_twig.js

@@ -0,0 +1,82 @@
+/*
+ * handlebars pattern engine for patternlab-node - v0.15.1 - 2015
+ *
+ * Geoffrey Pursell, Brian Muenzenmeyer, and the web community.
+ * Licensed under the MIT license.
+ *
+ * Many thanks to Brad Frost and Dave Olsen for inspiration, encouragement, and advice.
+ *
+ */
+
+/*
+ * ENGINE SUPPORT LEVEL:
+ *
+ * Full. Partial calls and lineage hunting are supported. Handlebars does not
+ * support the mustache-specific syntax extensions, style modifiers and pattern
+ * parameters, because their use cases are addressed by the core Handlebars
+ * feature set.
+ *
+ */
+
+"use strict";
+
+var Twig = require('twig/twig.js');
+var twig = Twig.twig;
+
+var engine_twig = {
+  engine: Twig,
+  engineName: 'twig',
+  engineFileExtension: '.twig',
+
+  //Important! Needed for Twig compilation. Can't resolve paths otherwise.
+  expandPartials: true,
+
+  // regexes, stored here so they're only compiled once
+  findPartialsRE: /{%([ ]+)?(?:extends|include|embed)(\s\S)(.*)%}/g,
+  findPartialKeyRE: /"((?:\\.|[^"\\])*)"/,
+  findListItemsRE: /({{#( )?)(list(I|i)tems.)(one|two|three|four|five|six|seven|eight|nine|ten|eleven|twelve|thirteen|fourteen|fifteen|sixteen|seventeen|eighteen|nineteen|twenty)( )?}}/g, // TODO
+
+  // render it
+  renderPattern: function renderPattern(template, data) {
+    var result = twig({
+      data: template
+    }).render(data);
+
+    return result;
+  },
+
+  // find and return any {{> template-name }} within pattern
+  findPartials: function findPartials(pattern) {
+    var matches = pattern.template.match(this.findPartialsRE);
+    return matches;
+  },
+  findPartialsWithStyleModifiers: function () {
+    // TODO: make the call to this from oPattern objects conditional on their
+    // being implemented here.
+    return [];
+  },
+
+  // returns any patterns that match {{> value(foo:"bar") }} or {{>
+  // value:mod(foo:"bar") }} within the pattern
+  findPartialsWithPatternParameters: function () {
+    // TODO: make the call to this from oPattern objects conditional on their
+    // being implemented here.
+    return [];
+  },
+  findListItems: function (pattern) {
+    var matches = pattern.template.match(this.findListItemsRE);
+    return matches;
+  },
+
+  // given a pattern, and a partial string, tease out the "pattern key" and
+  // return it.
+  findPartialKey: function (partialString) {
+    //var partialKey = partialString.replace(this.findPartialsRE, '$1');
+    var partialKey = partialString.match(this.findPartialKeyRE)[0];
+    partialKey = partialKey.replace(/"/g, '');
+
+    return partialKey;
+  }
+};
+
+module.exports = engine_twig;