Reorganise variable processing (part 2)

Processing page variables involves a two step process.

The first step extracts and renders locally declared page variables in
<variable> tags, using javascript proxies to force imported variables
to re-render as themselves again, which decreases code clarity.
The second step then extracts the imported variables, and stores such
variables into an alias map, then re-rendering the page a second time.

This process can be combined into a single pass to simplify the process
greatly and remove the need for workarounds like proxies.
This also increases rendering performance slightly, as only a single
pass is made

Moreover, variable tags in <include> tags are erroneously recognised as
page variables. Let's include a simple fix for this as well.

src/Site.js

@@ -688,7 +688,6 @@ class Site {
     const filePathArray = Array.isArray(filePaths) ? filePaths : [filePaths];
     const uniquePaths = _.uniq(filePathArray);
     logger.info('Rebuilding affected source files');
-    this.variablePreprocessor.resetVariables();
     return new Promise((resolve, reject) => {
       this.regenerateAffectedPages(uniquePaths)
         .then(() => fs.removeAsync(this.tempPath))
@@ -706,7 +705,6 @@ class Site {
     const uniqueUrls = _.uniq(normalizedUrlArray);
     uniqueUrls.forEach(normalizedUrl => logger.info(
       `Building ${normalizedUrl} as some of its dependencies were changed since the last visit`));
-    this.variablePreprocessor.resetVariables();
 
     /*
      Lazy loading only builds the page being viewed, but the user may be quick enough

src/lib/markbind/src/constants.js

@@ -5,11 +5,6 @@ module.exports = {
 
   BOILERPLATE_FOLDER_NAME: '_markbind/boilerplates',
 
-  /* Imported global variables will be assigned a namespace.
-   * A prefix is appended to reduce clashes with other variables in the page.
-   */
-  IMPORTED_VARIABLE_PREFIX: '$__MARKBIND__',
-
   // src/lib/markbind/src/utils.js
   markdownFileExts: ['md', 'mbd', 'mbdf'],
 };

src/lib/markbind/src/parser.js

@@ -235,21 +235,15 @@ class Parser {
         decodeEntities: true,
       });
 
-      const outerContentRendered = this.variablePreprocessor.renderOuterVariables(content, file,
-                                                                                  additionalVariables);
-      this.variablePreprocessor.extractInnerVariables(outerContentRendered, context.cwf)
-        .forEach(src => this.staticIncludeSrc.push(src));
-      const innerContentRendered = this.variablePreprocessor.renderInnerVariables(outerContentRendered,
-                                                                                  file, context.cwf,
-                                                                                  additionalVariables);
+      const renderedContent = this.variablePreprocessor.renderPage(file, content, additionalVariables);
 
       const fileExt = utils.getExt(file);
       if (utils.isMarkdownFileExt(fileExt)) {
         context.source = 'md';
-        parser.parseComplete(innerContentRendered.toString());
+        parser.parseComplete(renderedContent.toString());
       } else if (fileExt === 'html') {
         context.source = 'html';
-        parser.parseComplete(innerContentRendered);
+        parser.parseComplete(renderedContent);
       } else {
         const error = new Error(`Unsupported File Extension: '${fileExt}'`);
         reject(error);

src/lib/markbind/src/preprocessors/componentPreprocessor.js

@@ -244,9 +244,7 @@ function _preprocessInclude(node, context, config, parser) {
   const {
     renderedContent,
     childContext,
-    includedSrces,
   } = variablePreprocessor.renderIncludeFile(actualFilePath, element, context, filePath);
-  includedSrces.forEach(src => parser.staticIncludeSrc.push(src));
 
   _deleteIncludeAttributes(element);
 
@@ -317,6 +315,16 @@ function _preprocessVariables() {
   return utils.createEmptyNode();
 }
 
+function _preprocessImports(node, parser) {
+  if (node.attribs.from) {
+    parser.staticIncludeSrc.push({
+      from: node.attribs.cwf,
+      to: path.resolve(node.attribs.cwf, node.attribs.from),
+    });
+  }
+
+  return utils.createEmptyNode();
+}
 
 /*
  * Body
@@ -343,8 +351,9 @@ function preProcessComponent(node, context, config, parser) {
   case 'panel':
     return _preProcessPanel(element, context, config, parser);
   case 'variable':
-  case 'import':
     return _preprocessVariables();
+  case 'import':
+    return _preprocessImports(node, parser);
   case 'include':
     return _preprocessInclude(element, context, config, parser);
   case 'body':