Add maximum parameter to MD012/no-multiple-blanks (fixes #27).

doc/Rules.md

@@ -306,6 +306,8 @@ Tags: whitespace, blank_lines
 
 Aliases: no-multiple-blanks
 
+Parameters: maximum (number; default 1)
+
 This rule is triggered when there are multiple consecutive blank lines in the
 document:
 
@@ -323,6 +325,9 @@ To fix this, delete the offending lines:
 Note: this rule will not be triggered if there are multiple consecutive blank
 lines inside code blocks.
 
+Note: The `maximum` parameter can be used to configure the maximum number of
+consecutive blank lines.
+
 ## MD013 - Line length
 
 Tags: line_length

lib/rules.js

@@ -358,13 +358,13 @@ module.exports = [
     "tags": [ "whitespace", "blank_lines" ],
     "aliases": [ "no-multiple-blanks" ],
     "func": function MD012(params, errors) {
-      var prevLine = "-";
+      var maximum = params.options.maximum || 1;
+      var count = 0;
       forEachLine(params, function forLine(line, lineIndex, inCode) {
-        line = line.trim();
-        if (!inCode && !line.length && !prevLine.length) {
+        count = (inCode || line.trim().length) ? 0 : count + 1;
+        if (maximum < count) {
           errors.push(lineIndex + 1);
         }
-        prevLine = line;
       });
     }
   },

test/markdownlint-test.js

@@ -857,7 +857,7 @@ module.exports.readme = function readme(test) {
 };
 
 module.exports.doc = function doc(test) {
-  test.expect(294);
+  test.expect(295);
   fs.readFile("doc/Rules.md", shared.utf8Encoding,
     function readFile(err, contents) {
       test.ifError(err);

test/no-multiple-blanks-maximum.json

@@ -0,0 +1,6 @@
+{
+  "default": true,
+  "MD012": {
+    "maximum": 3
+  }
+}

test/no-multiple-blanks-maximum.md

@@ -0,0 +1,46 @@
+# Heading
+
+Text
+
+Text
+
+
+Text
+
+
+
+Text
+
+
+
+
+Text {MD012:16}
+
+
+
+
+
+Text {MD012:21} {MD012:22}
+
+
+
+
+
+
+Text {MD012:27} {MD012:28} {MD012:29}
+
+Text
+
+
+
+
+Text {MD012:36}
+
+
+
+Text
+
+
+Text
+
+Text

test/no-multiple-blanks.md

@@ -0,0 +1,24 @@
+# Heading
+
+Text
+
+Text
+
+
+Text {MD012:7}
+
+
+
+Text {MD012:10} {MD012:11}
+
+
+
+
+Text {MD012:14} {MD012:15} {MD012:16}
+
+Text
+
+
+Text {MD012:21}
+
+Text