Add MD002 with test, incorporate markdown-it parser.

lib/markdownlint.js

@@ -1,6 +1,7 @@
 "use strict";
 
 var fs = require("fs");
+var md = require("markdown-it")();
 var rules = require("./rules");
 
 function numberComparison(a, b) {
@@ -16,10 +17,11 @@ function lintFile(file, options, callback) {
     if (err) {
       callback(err);
     } else {
-      var lines = contents.split(/\r\n|\n/g);
+      var tokens = md.parse(contents);
+      var lines = contents.split(/\r\n|\r|\n/g);
       var result = {};
       rules.forEach(function forRule(rule) {
-        var errors = rule.func(lines);
+        var errors = rule.func(tokens, lines);
         if (errors.length) {
           errors.sort(numberComparison);
           result[rule.name] = errors.filter(uniqueFilterForSorted);

lib/rules.js

@@ -10,10 +10,26 @@ function padAndTrim(lines) {
 }
 
 module.exports = [
+  {
+    "name": "MD002",
+    "desc": "First header should be a h1 header",
+    "func": function MD002(tokens) {
+      var errors = [];
+      tokens.every(function forToken(token) {
+        if ((token.type === "heading_open") && (token.hLevel !== 1)) {
+          errors.push(token.lines[0] + 1);
+          return false;
+        }
+        return true;
+      });
+      return errors;
+    }
+  },
+
   {
     "name": "MD031",
     "desc": "Fenced code blocks should be surrounded by blank lines",
-    "func": function MD031(lines) {
+    "func": function MD031(tokens, lines) {
       // Some parsers have trouble detecting fenced code blocks without
       // surrounding whitespace, so examine the lines directly.
       lines = padAndTrim(lines);
@@ -35,7 +51,7 @@ module.exports = [
   {
     "name": "MD032",
     "desc": "Lists should be surrounded by blank lines",
-    "func": function MD032(lines) {
+    "func": function MD032(tokens, lines) {
       // Some parsers have trouble detecting lists without surrounding
       // whitespace, so examine the lines directly.
       var errors = [];

package.json

@@ -17,6 +17,9 @@
     "test": "nodeunit",
     "lint": "eslint lib test"
   },
+  "dependencies": {
+    "markdown-it": "^3.0.7"
+  },
   "devDependencies": {
     "eslint": "^0.15.0",
     "nodeunit": "^0.9.0"

test/first_header_bad_atx.md

@@ -0,0 +1 @@
+## Header {MD002}

test/first_header_bad_setext.md

@@ -0,0 +1,2 @@
+Header {MD002}
+--------------

test/markdownlint-test.js

@@ -12,7 +12,7 @@ function createTestForFile(file) {
       { "encoding": "utf8" },
       function readFileCallback(err, contents) {
         test.ifError(err);
-        var lines = contents.split(/\r\n|\n/g);
+        var lines = contents.split(/\r\n|\r|\n/g);
         var results = {};
         lines.forEach(function forLine(line, lineNum) {
           var match = line.match(/\{(MD\d+)(?::(\d+))?\}/);