Add code_blocks parameter to MD010 to ignore hard tabs in code blocks (fixes #31).

doc/Rules.md

@@ -258,6 +258,8 @@ Tags: whitespace, hard_tab
 
 Aliases: no-hard-tabs
 
+Parameters: code_blocks (boolean; default true)
+
 This rule is triggered by any lines that contain hard tab characters instead
 of using spaces for indentation. To fix this, replace any hard tab characters
 with spaces instead.
@@ -274,6 +276,10 @@ Corrected example:
 
         * Spaces used to indent the list item instead
 
+You have the option to exclude this rule for code blocks. To do so, set the
+`code_blocks` parameter to `false`. Code blocks are included by default since
+handling of tabs by tools is often inconsistent (ex: using 4 vs. 8 spaces).
+
 ## MD011 - Reversed link syntax
 
 Tags: links

lib/rules.js

@@ -328,8 +328,10 @@ module.exports = [
     "tags": [ "whitespace", "hard_tab" ],
     "aliases": [ "no-hard-tabs" ],
     "func": function MD010(params, errors) {
-      params.lines.forEach(function forLine(line, lineIndex) {
-        if (/\t/.test(line)) {
+      var codeBlocks = params.options.code_blocks;
+      var includeCodeBlocks = (codeBlocks === undefined) ? true : !!codeBlocks;
+      forEachLine(params, function forLine(line, lineIndex, inCode) {
+        if (/\t/.test(line) && (!inCode || includeCodeBlocks)) {
           errors.push(lineIndex + 1);
         }
       });

test/code-block-with-tabs-allowed.json

@@ -0,0 +1,6 @@
+{
+  "default": true,
+  "MD010": {
+    "code_blocks": false
+  }
+}

test/code-block-with-tabs-allowed.md

@@ -0,0 +1,35 @@
+# Heading
+
+```js
+if (true) {
+    console.log("true");
+    if (false) {
+        console.log("false");
+    }
+}
+```
+
+```js
+if (true) {
+	console.log("true");
+	if (false) {
+		console.log("false");
+	}
+}
+```
+
+    if (true) {
+        console.log("true");
+        if (false) {
+            console.log("false");
+        }
+    }
+
+	if (true) {
+		console.log("true");
+		if (false) {
+			console.log("false");
+		}
+	}
+
+Line with	hard tab. {MD010}

test/code-block-with-tabs.md

@@ -0,0 +1,35 @@
+# Heading
+
+```js
+if (true) {
+    console.log("true");
+    if (false) {
+        console.log("false");
+    }
+}
+```
+
+```js
+if (true) {
+	console.log("true");      // {MD010}
+	if (false) {              // {MD010}
+		console.log("false"); // {MD010}
+	}                         // {MD010}
+}
+```
+
+    if (true) {
+        console.log("true");
+        if (false) {
+            console.log("false");
+        }
+    }
+
+	if (true) {                   // {MD010}
+		console.log("true");      // {MD010}
+		if (false) {              // {MD010}
+			console.log("false"); // {MD010}
+		}                         // {MD010}
+	}                             // {MD010}
+
+Line with	hard tab. {MD010}

test/markdownlint-test.js

@@ -857,7 +857,7 @@ module.exports.readme = function readme(test) {
 };
 
 module.exports.doc = function doc(test) {
-  test.expect(293);
+  test.expect(294);
   fs.readFile("doc/Rules.md", shared.utf8Encoding,
     function readFile(err, contents) {
       test.ifError(err);