Add markdown extension mechanism and syntax

README.md

@@ -267,6 +267,13 @@ Default: `false`
 
 Use "smart" typograhic punctuation for things like quotes and dashes.
 
+### plugins
+
+Type: `boolean`
+Default: `false`
+
+Enable plugin syntax.
+
 ## Access to lexer and parser
 
 You also have direct access to the lexer and parser if you so desire.
@@ -358,6 +365,45 @@ $ node
   links: {} ]
 ```
 
+## Plugin syntax
+
+Plugins are customizable blocks which could extend default markdown behavior
+on demand. It could be iframes, podcasts, UML diagrams, video, etc. Plugin block
+starts with '@', plugin name and params in round braces. Plugin could contain
+block of data. Data block should preserve indentation it allow to add any
+content with any markup inside of the block.
+
+```
+@uml(sequence)
+  Alice->Bob: Hi, Bob!
+  Bob->Alice: Hi, Alice!
+```
+If plugin not exists it's just ignoring.
+
+### Define plugin
+
+Plugins could be defined at runtime or for all marked instances:
+
+```javascript
+// Define default plugin
+marked.Renderer.plugins.video = function(params) {
+  return `<video src="${params}"/>`;
+};
+
+// Instance plugins
+var renderer = new marked.Renderer({
+  plugins: {
+    uml(params, block) {
+      //...
+    }
+  }
+});
+
+renderer.plugins.audio = function(params) {
+  return `<audio src="${params}"/>`;
+};
+```
+
 ## Running Tests & Contributing
 
 If you want to submit a pull request, make sure your changes pass the test

examples/plugin.js

@@ -0,0 +1,64 @@
+'use strict';
+
+var marked = require('marked');
+var csv = require('csv-string');
+var html = require('escape-html');
+
+// Enable plugins for all instances
+marked.setOptions({plugins: true});
+
+// Initialize renderer
+var renderer = new marked.Renderer({
+  plugins: {
+    // Convert `@link(title,url)` into link.
+    links: function(params, block) {
+      var parts = params.split(/\s*,\s*/);
+      return '<a href="' + html(parts[1]) + '">' + html(parts[0]) + '</a>';
+    },
+
+    // Convert `@github(user/repo)` into github link.
+    github: function(params, block) {
+      return '<a href="https://github.com/' + html(params) + '">' + html(params) + '</a>';
+    },
+
+    // Convert `@csv(headers)` block data into table.
+    csv: function(params, block) {
+      var thead = params.length ? params.split(/\s*,\s*/) : null;
+      var tbody = csv.parse(block);
+
+      var table = ['<table>']; // Use array to avoid string reallocations
+      if (thead) {
+        table.push('<thead><tr>');
+        thead.forEach(function(heading) {
+          table.push('<th>' + html(heading) + "</th>");
+        });
+        table.push('</tr></thead>');
+      }
+      table.push('<tbody>');
+      tbody.forEach(function(row) {
+        table.push('<tr>');
+        row.forEach(function(cell) {
+          table.push('<td>' + html(cell) + "</td>");
+        });
+        table.push('</tr>');
+      });
+      table.push('</tbody></table>');
+
+      return table.join('\n');
+    },
+    gallery(params, block) {
+      var gallery = ['<ul class="imageGallery">'];
+      block.replace(/^\s+|\s+$/gm, '').split(/\s+\r?\n\s+/).forEach(function(img) {
+        gallery.push('<li class="imageGallery-item"><img src="' + html(img) + '"/></li>');
+      });
+      gallery.push('</ul>');
+      return gallery.join('\n');
+    }
+  }
+});
+
+// Add plugin to initialized renderer.
+// Parse block of markdown inside markdown. Yep even so :)
+renderer.plugins.markdown = function(params, block) {
+  return marked(block, {renderer: this});
+};

lib/marked.js

@@ -24,7 +24,7 @@ var block = {
   def: /^ *\[([^\]]+)\]: *<?([^\s>]+)>?(?: +["(]([^\n]+)[")])? *(?:\n+|$)/,
   table: noop,
   paragraph: /^((?:[^\n]+\n?(?!hr|heading|lheading|blockquote|tag|def))+)\n*/,
-  text: /^[^\n]+/
+  text: /^[^\n]+/,
 };
 
 block.bullet = /(?:[*+-]|\d+\.)/;
@@ -95,6 +95,10 @@ block.tables = merge({}, block.gfm, {
   table: /^ *\|(.+)\n *\|( *[-:]+[-| :]*)\n((?: *\|.*(?:\n|$))*)\n*/
 });
 
+block.extra = {
+  plugin: /^@(!?[A-Za-z0-9_-]+) *\( *((.+) *)?\).*?\n((\s{2,}|\t{1,}).+\n(((\5).*\n)|\n)*)?/,
+};
+
 /**
  * Block Lexer
  */
@@ -103,15 +107,22 @@ function Lexer(options) {
   this.tokens = [];
   this.tokens.links = {};
   this.options = options || marked.defaults;
-  this.rules = block.normal;
-
+  var rules;
   if (this.options.gfm) {
     if (this.options.tables) {
-      this.rules = block.tables;
+      rules = merge({}, block.tables);
     } else {
-      this.rules = block.gfm;
+      rules = merge({}, block.gfm);
     }
+  } else {
+    rules = merge({}, block.normal);
   }
+
+  if (this.options.plugins) {
+    rules.plugin = block.extra.plugin;
+  }
+
+  this.rules = rules;
 }
 
 /**
@@ -183,6 +194,18 @@ Lexer.prototype.token = function(src, top, bq) {
       continue;
     }
 
+    // code
+    if (this.rules.plugin && (cap = this.rules.plugin.exec(src))) {
+      src = src.substring(cap[0].length);
+      this.tokens.push({
+        type: 'plugin',
+        plugin: cap[1],
+        params: cap[3],
+        block: cap[4] !== undefined ? cap[4].replace(new RegExp('^' + cap[4].match(/^\s+/)[0], 'gm'), '') : undefined,
+      });
+      continue;
+    }
+
     // fences (gfm)
     if (cap = this.rules.fences.exec(src)) {
       src = src.substring(cap[0].length);
@@ -759,6 +782,7 @@ InlineLexer.prototype.mangle = function(text) {
 
 function Renderer(options) {
   this.options = options || {};
+  this.plugins = merge({}, this.plugins, this.options.plugins);
 }
 
 Renderer.prototype.code = function(code, lang, escaped) {
@@ -784,6 +808,24 @@ Renderer.prototype.code = function(code, lang, escaped) {
     + '\n</code></pre>\n';
 };
 
+Renderer.prototype.plugin = function(plugin, params, block) {
+  if (plugin.charAt(0) === '!') {
+    if (! this.plugins.hasOwnProperty(plugin)) {
+      return block;
+    } else {
+      return '';
+    }
+  } else {
+    if (this.plugins.hasOwnProperty(plugin)) {
+      return this.plugins[plugin].call(this, params, block);
+    } else {
+      return '';
+    }
+  }
+};
+
+Renderer.prototype.plugins = Renderer.plugins = {};
+
 Renderer.prototype.blockquote = function(quote) {
   return '<blockquote>\n' + quote + '</blockquote>\n';
 };
@@ -991,6 +1033,12 @@ Parser.prototype.tok = function() {
         this.token.lang,
         this.token.escaped);
     }
+    case 'plugin': {
+        return this.renderer.plugin(
+          this.token.plugin,
+          this.token.params,
+          this.token.block);
+    }
     case 'table': {
       var header = ''
         , body = ''
@@ -1094,7 +1142,7 @@ function escape(html, encode) {
 }
 
 function unescape(html) {
-	// explicitly match decimal, hex, and named HTML entities 
+	// explicitly match decimal, hex, and named HTML entities
   return html.replace(/&(#(?:\d+)|(?:#x[0-9A-Fa-f]+)|(?:\w+));?/g, function(_, n) {
     n = n.toLowerCase();
     if (n === 'colon') return ':';
@@ -1253,7 +1301,8 @@ marked.defaults = {
   smartypants: false,
   headerPrefix: '',
   renderer: new Renderer,
-  xhtml: false
+  xhtml: false,
+  plugins: false
 };
 
 /**

test/index.js

@@ -82,6 +82,19 @@ function runTests(engine, options) {
     marked.setOptions(options.marked);
   }
 
+  engine.setOptions({plugins: true});
+
+  var renderer = new marked.Renderer();
+  renderer.plugins = {};
+  renderer.plugins.github = function(params, body) {
+    return '<a href="https://github.com/' + body + '">' + body + '</a>';
+  };
+
+  renderer.plugins.link = function(params, body) {
+    var parts = params.split(/\s*,\s*/);
+    return '<a href="' + parts[1] + '">' + parts[0] + '</a>';
+  };
+
 main:
   for (; i < len; i++) {
     filename = keys[i];
@@ -112,7 +125,7 @@ main:
     }
 
     try {
-      text = engine(file.text).replace(/\s/g, '');
+      text = engine(file.text, {renderer: renderer}).replace(/\s/g, '');
       html = file.html.replace(/\s/g, '');
     } catch(e) {
       console.log('%s failed.', filename);

test/tests/plugin_github.html

@@ -0,0 +1,3 @@
+<a href="https://github.com">github</a>
+<a href="https://github.com/chjj/marked">chjj/marked</a>
+NoYoutubePlugin

test/tests/plugin_github.text

@@ -0,0 +1,10 @@
+@link(github, https://github.com)
+
+@github(https)
+  chjj/marked
+
+@no()
+  Ignore
+
+@!youtube()
+  No Youtube Plugin