add metadata

docs/event_system.md

@@ -27,7 +27,7 @@ Note:
 This object holds the text captured by the subparser. The properties of this object
 are different for each subparser.
 
-Properties whose name starts with `_` are readonly.
+**Properties whose name starts with `_` are readonly**.
 
 Example:
 
@@ -214,3 +214,15 @@ These events are always guaranteed to be called, regardless of options or circum
 ### blockquote
 
 #### 
+
+
+### metadata
+
+
+
+## Common pitfalls
+
+### Infinite loop
+
+If you pass the input as output in a `onCapture` event, you might trigger an infinite loop. 
+

src/subParsers/makehtml/metadata.js

@@ -8,11 +8,50 @@ showdown.subParser('makehtml.metadata', function (text, options, globals) {
     return text;
   }
 
-  text = globals.converter._dispatch('makehtml.metadata.before', text, options, globals).getText();
+  let startEvent = new showdown.Event('makehtml.metadata.onStart', text);
+  startEvent
+    .setOutput(text)
+    ._setGlobals(globals)
+    ._setOptions(options);
+  startEvent = globals.converter.dispatch(startEvent);
+  text = startEvent.output;
+
+  /**
+   * @param {RegExp} pattern
+   * @param {string} wholeMatch
+   * @param {string} format
+   * @param {string} content
+   * @returns {string}
+   */
+  function parseMetadataContents (pattern, wholeMatch, format, content) {
+    let otp;
+    let captureStartEvent = new showdown.Event('makehtml.metadata.onCapture', content);
+    captureStartEvent
+      .setOutput(null)
+      ._setGlobals(globals)
+      ._setOptions(options)
+      .setRegexp(pattern)
+      .setMatches({
+        _wholeMatch: wholeMatch,
+        format: format,
+        content: content
+      })
+      .setAttributes({});
+    captureStartEvent = globals.converter.dispatch(captureStartEvent);
+
+    format = captureStartEvent.matches.format;
+    content = captureStartEvent.matches.content;
+
+    // if something was passed as output, it will be used as output
+    if (captureStartEvent.output && captureStartEvent.output !== '') {
+      otp = captureStartEvent.output;
+    } else {
+      otp = '¨M';
+    }
 
-  function parseMetadataContents (content) {
     // raw is raw so it's not changed in any way
     globals.metadata.raw = content;
+    globals.metadata.format = format;
 
     // escape chars forbidden in html attributes
     // double quotes
@@ -20,35 +59,47 @@ showdown.subParser('makehtml.metadata', function (text, options, globals) {
       // ampersand first
       .replace(/&/g, '&')
       // double quotes
-      .replace(/"/g, '"');
-
+      .replace(/"/g, '"')
     // Restore dollar signs and tremas
-    content = content
       .replace(/¨D/g, '$$')
-      .replace(/¨T/g, '¨');
+      .replace(/¨T/g, '¨')
+      // replace multiple spaces
+      .replace(/\n {4}/g, ' ');
 
-    content = content.replace(/\n {4}/g, ' ');
     content.replace(/^([\S ]+): +([\s\S]+?)$/gm, function (wm, key, value) {
       globals.metadata.parsed[key] = value;
       return '';
     });
+    let beforeHashEvent = new showdown.Event('makehtml.metadata.onHash', otp);
+    beforeHashEvent
+      .setOutput(otp)
+      ._setGlobals(globals)
+      ._setOptions(options);
+    beforeHashEvent = globals.converter.dispatch(beforeHashEvent);
+    otp = beforeHashEvent.output;
+    if (!otp) {
+      otp = '¨M';
+    }
+    return otp;
   }
 
-  text = text.replace(/^\s*«««+\s*(\S*?)\n([\s\S]+?)\n»»»+\s*\n/, function (wholematch, format, content) {
-    parseMetadataContents(content);
-    return '¨M';
+  // 1. Metadata with «««»»» delimiters
+  const rgx1 = /^\s*«««+\s*(\S*?)\n([\s\S]+?)\n»»»+\s*\n/;
+  text = text.replace(rgx1, function (wholeMatch, format, content) {
+    return parseMetadataContents(rgx1, wholeMatch, format, content);
   });
 
-  text = text.replace(/^\s*---+\s*(\S*?)\n([\s\S]+?)\n---+\s*\n/, function (wholematch, format, content) {
-    if (format) {
-      globals.metadata.format = format;
-    }
-    parseMetadataContents(content);
-    return '¨M';
+  // 2. Metadata with YAML delimiters
+  const rgx2 = /^\s*---+\s*(\S*?)\n([\s\S]+?)\n---+\s*\n/;
+  text = text.replace(rgx2, function (wholeMatch, format, content) {
+    return parseMetadataContents(rgx1, wholeMatch, format, content);
   });
-
   text = text.replace(/¨M/g, '');
-
-  text = globals.converter._dispatch('makehtml.metadata.after', text, options, globals).getText();
-  return text;
+  let afterEvent = new showdown.Event('makehtml.metadata.onEnd', text);
+  afterEvent
+    .setOutput(text)
+    ._setGlobals(globals)
+    ._setOptions(options);
+  afterEvent = globals.converter.dispatch(afterEvent);
+  return afterEvent.output;
 });