--- /dev/null
+'use strict';
+
+var trim = require('trim-trailing-lines');
+
+module.exports = fencedCode;
+
+var C_NEWLINE = '\n';
+var C_TAB = '\t';
+var C_SPACE = ' ';
+var C_TILDE = '~';
+var C_TICK = '`';
+
+var MIN_FENCE_COUNT = 3;
+var CODE_INDENT_COUNT = 4;
+
+function fencedCode(eat, value, silent) {
+ var self = this;
+ var settings = self.options;
+ var length = value.length + 1;
+ var index = 0;
+ var subvalue = '';
+ var fenceCount;
+ var marker;
+ var character;
+ var flag;
+ var queue;
+ var content;
+ var exdentedContent;
+ var closing;
+ var exdentedClosing;
+ var indent;
+ var now;
+
+ if (!settings.gfm) {
+ return;
+ }
+
+ /* Eat initial spacing. */
+ while (index < length) {
+ character = value.charAt(index);
+
+ if (character !== C_SPACE && character !== C_TAB) {
+ break;
+ }
+
+ subvalue += character;
+ index++;
+ }
+
+ indent = index;
+
+ /* Eat the fence. */
+ character = value.charAt(index);
+
+ if (character !== C_TILDE && character !== C_TICK) {
+ return;
+ }
+
+ index++;
+ marker = character;
+ fenceCount = 1;
+ subvalue += character;
+
+ while (index < length) {
+ character = value.charAt(index);
+
+ if (character !== marker) {
+ break;
+ }
+
+ subvalue += character;
+ fenceCount++;
+ index++;
+ }
+
+ if (fenceCount < MIN_FENCE_COUNT) {
+ return;
+ }
+
+ /* Eat spacing before flag. */
+ while (index < length) {
+ character = value.charAt(index);
+
+ if (character !== C_SPACE && character !== C_TAB) {
+ break;
+ }
+
+ subvalue += character;
+ index++;
+ }
+
+ /* Eat flag. */
+ flag = '';
+ queue = '';
+
+ while (index < length) {
+ character = value.charAt(index);
+
+ if (
+ character === C_NEWLINE ||
+ character === C_TILDE ||
+ character === C_TICK
+ ) {
+ break;
+ }
+
+ if (character === C_SPACE || character === C_TAB) {
+ queue += character;
+ } else {
+ flag += queue + character;
+ queue = '';
+ }
+
+ index++;
+ }
+
+ character = value.charAt(index);
+
+ if (character && character !== C_NEWLINE) {
+ return;
+ }
+
+ if (silent) {
+ return true;
+ }
+
+ now = eat.now();
+ now.column += subvalue.length;
+ now.offset += subvalue.length;
+
+ subvalue += flag;
+ flag = self.decode.raw(self.unescape(flag), now);
+
+ if (queue) {
+ subvalue += queue;
+ }
+
+ queue = '';
+ closing = '';
+ exdentedClosing = '';
+ content = '';
+ exdentedContent = '';
+
+ /* Eat content. */
+ while (index < length) {
+ character = value.charAt(index);
+ content += closing;
+ exdentedContent += exdentedClosing;
+ closing = '';
+ exdentedClosing = '';
+
+ if (character !== C_NEWLINE) {
+ content += character;
+ exdentedClosing += character;
+ index++;
+ continue;
+ }
+
+ /* Add the newline to `subvalue` if its the first
+ * character. Otherwise, add it to the `closing`
+ * queue. */
+ if (content) {
+ closing += character;
+ exdentedClosing += character;
+ } else {
+ subvalue += character;
+ }
+
+ queue = '';
+ index++;
+
+ while (index < length) {
+ character = value.charAt(index);
+
+ if (character !== C_SPACE) {
+ break;
+ }
+
+ queue += character;
+ index++;
+ }
+
+ closing += queue;
+ exdentedClosing += queue.slice(indent);
+
+ if (queue.length >= CODE_INDENT_COUNT) {
+ continue;
+ }
+
+ queue = '';
+
+ while (index < length) {
+ character = value.charAt(index);
+
+ if (character !== marker) {
+ break;
+ }
+
+ queue += character;
+ index++;
+ }
+
+ closing += queue;
+ exdentedClosing += queue;
+
+ if (queue.length < fenceCount) {
+ continue;
+ }
+
+ queue = '';
+
+ while (index < length) {
+ character = value.charAt(index);
+
+ if (character !== C_SPACE && character !== C_TAB) {
+ break;
+ }
+
+ closing += character;
+ exdentedClosing += character;
+ index++;
+ }
+
+ if (!character || character === C_NEWLINE) {
+ break;
+ }
+ }
+
+ subvalue += content + closing;
+
+ return eat(subvalue)({
+ type: 'code',
+ lang: flag || null,
+ value: trim(exdentedContent)
+ });
+}