Update MD013/line-length with heading_line_length parameter (fixes #170).

doc/Rules.md

@@ -443,13 +443,14 @@ Tags: line_length
 
 Aliases: line-length
 
-Parameters: line_length, code_blocks, tables, headings, headers (number; default 80, boolean; default true)
+Parameters: line_length, heading_line_length, code_blocks, tables, headings, headers (number; default 80, boolean; default true)
 
 > If `headings` is not provided, `headers` (deprecated) will be used.
 
 This rule is triggered when there are lines that are longer than the
-configured line length (default: 80 characters). To fix this, split the line
-up into multiple lines.
+configured `line_length` (default: 80 characters). To fix this, split the line
+up into multiple lines. To set a different maximum length for headings, use
+`heading_line_length`.
 
 This rule has an exception where there is no whitespace beyond the configured
 line length. This allows you to still include items such as long URLs without

lib/md013.js

@@ -3,8 +3,23 @@
 "use strict";
 
 const shared = require("./shared");
+const {
+  addErrorDetailIf, filterTokens, forEachHeading, forEachLine, rangeFromRegExp
+} = shared;
 
+const longLineRePrefix = "^(.{";
+const longLineRePostfix = "})(.*\\s.*)$";
 const labelRe = /^\s*\[.*[^\\]]:/;
+const linkOnlyLineRe = /^[es]*lT?L[ES]*$/;
+const tokenTypeMap = {
+  "em_open": "e",
+  "em_close": "E",
+  "link_open": "l",
+  "link_close": "L",
+  "strong_open": "s",
+  "strong_close": "S",
+  "text": "T"
+};
 
 module.exports = {
   "names": [ "MD013", "line-length" ],
@@ -12,6 +27,11 @@ module.exports = {
   "tags": [ "line_length" ],
   "function": function MD013(params, onError) {
     const lineLength = params.config.line_length || 80;
+    const headingLineLength = params.config.heading_line_length || lineLength;
+    const longLineRe =
+      new RegExp(longLineRePrefix + lineLength + longLineRePostfix);
+    const longHeadingLineRe =
+      new RegExp(longLineRePrefix + headingLineLength + longLineRePostfix);
     const codeBlocks = params.config.code_blocks;
     const includeCodeBlocks = (codeBlocks === undefined) ? true : !!codeBlocks;
     const tables = params.config.tables;
@@ -22,44 +42,34 @@ module.exports = {
     }
     const includeHeadings = (headings === undefined) ? true : !!headings;
     const headingLineNumbers = [];
-    if (!includeHeadings) {
-      shared.forEachHeading(params, function forHeading(heading) {
+    forEachHeading(params, (heading) => {
       headingLineNumbers.push(heading.lineNumber);
     });
-    }
-    const tokenTypeMap = {
-      "em_open": "e",
-      "em_close": "E",
-      "link_open": "l",
-      "link_close": "L",
-      "strong_open": "s",
-      "strong_close": "S",
-      "text": "T"
-    };
     const linkOnlyLineNumbers = [];
-    shared.filterTokens(params, "inline", function forToken(token) {
+    filterTokens(params, "inline", (token) => {
       let childTokenTypes = "";
-      token.children.forEach(function forChild(child) {
+      token.children.forEach((child) => {
         if (child.type !== "text" || child.content !== "") {
           childTokenTypes += tokenTypeMap[child.type] || "x";
         }
       });
-      if (/^[es]*lT?L[ES]*$/.test(childTokenTypes)) {
+      if (linkOnlyLineRe.test(childTokenTypes)) {
         linkOnlyLineNumbers.push(token.lineNumber);
       }
     });
-    const longLineRe = new RegExp("^(.{" + lineLength + "})(.*\\s.*)$");
-    shared.forEachLine(
-      function forLine(line, lineIndex, inCode, onFence, inTable) {
+    forEachLine((line, lineIndex, inCode, onFence, inTable) => {
       const lineNumber = lineIndex + 1;
+      const isHeading = headingLineNumbers.indexOf(lineNumber) >= 0;
+      const length = isHeading ? headingLineLength : lineLength;
+      const lengthRe = isHeading ? longHeadingLineRe : longLineRe;
       if ((includeCodeBlocks || !inCode) &&
           (includeTables || !inTable) &&
-            (includeHeadings || (headingLineNumbers.indexOf(lineNumber)) < 0) &&
+          (includeHeadings || !isHeading) &&
           (linkOnlyLineNumbers.indexOf(lineNumber) < 0) &&
-            longLineRe.test(line) &&
+          lengthRe.test(line) &&
           !labelRe.test(line)) {
-          shared.addErrorDetailIf(onError, lineNumber, lineLength,
-            line.length, null, null, shared.rangeFromRegExp(line, longLineRe));
+        addErrorDetailIf(onError, lineNumber, length, line.length,
+          null, null, rangeFromRegExp(line, lengthRe));
       }
     });
   }

schema/build-config-schema.js

@@ -129,6 +129,11 @@ rules.forEach(function forRule(rule) {
           "type": "integer",
           "default": 80
         },
+        "heading_line_length": {
+          "description": "Number of characters for headings",
+          "type": "integer",
+          "default": 80
+        },
         "code_blocks": {
           "description": "Include code blocks",
           "type": "boolean",

schema/markdownlint-config-schema.json

@@ -374,6 +374,11 @@
           "type": "integer",
           "default": 80
         },
+        "heading_line_length": {
+          "description": "Number of characters for headings",
+          "type": "integer",
+          "default": 80
+        },
         "code_blocks": {
           "description": "Include code blocks",
           "type": "boolean",
@@ -410,6 +415,11 @@
           "type": "integer",
           "default": 80
         },
+        "heading_line_length": {
+          "description": "Number of characters for headings",
+          "type": "integer",
+          "default": 80
+        },
         "code_blocks": {
           "description": "Include code blocks",
           "type": "boolean",

test/detailed-results-MD011-MD021.json

@@ -0,0 +1,6 @@
+{
+  "default": true,
+  "MD013": {
+    "heading_line_length": 40
+  }
+}

test/detailed-results-MD011-MD021.md

@@ -7,6 +7,8 @@ A (reversed)[link] example.
 
 123456789 123456789 123456789 123456789 123456789 123456789 123456789 123456789 123456789 123456789
 
+## 123456789 123456789 123456789 123456789 123456789 123456789
+
     $ command with no output
 
 ##No space A

test/detailed-results-MD011-MD021.results.json

@@ -28,6 +28,15 @@
     },
     {
         "lineNumber": 10,
+        "ruleNames": [ "MD013", "line-length" ],
+        "ruleDescription": "Line length",
+        "ruleInformation": "https://github.com/DavidAnson/markdownlint/blob/v0.0.0/doc/Rules.md#md013",
+        "errorDetail": "Expected: 40; Actual: 62",
+        "errorContext": null,
+        "errorRange": [41, 22]
+    },
+    {
+        "lineNumber": 12,
         "ruleNames": [ "MD014", "commands-show-output" ],
         "ruleDescription": "Dollar signs used before commands without showing output",
         "ruleInformation": "https://github.com/DavidAnson/markdownlint/blob/v0.0.0/doc/Rules.md#md014",
@@ -36,7 +45,7 @@
         "errorRange": [5, 2]
     },
     {
-        "lineNumber": 12,
+        "lineNumber": 14,
         "ruleNames": [ "MD018", "no-missing-space-atx" ],
         "ruleDescription": "No space after hash on atx style heading",
         "ruleInformation": "https://github.com/DavidAnson/markdownlint/blob/v0.0.0/doc/Rules.md#md018",
@@ -45,7 +54,7 @@
         "errorRange": [1, 3]
     },
     {
-        "lineNumber": 14,
+        "lineNumber": 16,
         "ruleNames": [ "MD019", "no-multiple-space-atx" ],
         "ruleDescription": "Multiple spaces after hash on atx style heading",
         "ruleInformation": "https://github.com/DavidAnson/markdownlint/blob/v0.0.0/doc/Rules.md#md019",
@@ -54,7 +63,7 @@
         "errorRange": [1, 5]
     },
     {
-        "lineNumber": 16,
+        "lineNumber": 18,
         "ruleNames": [ "MD020", "no-missing-space-closed-atx" ],
         "ruleDescription": "No space inside hashes on closed atx style heading",
         "ruleInformation": "https://github.com/DavidAnson/markdownlint/blob/v0.0.0/doc/Rules.md#md020",
@@ -63,7 +72,7 @@
         "errorRange": [1, 3]
     },
     {
-        "lineNumber": 18,
+        "lineNumber": 20,
         "ruleNames": [ "MD020", "no-missing-space-closed-atx" ],
         "ruleDescription": "No space inside hashes on closed atx style heading",
         "ruleInformation": "https://github.com/DavidAnson/markdownlint/blob/v0.0.0/doc/Rules.md#md020",
@@ -72,7 +81,7 @@
         "errorRange": [13, 3]
     },
     {
-        "lineNumber": 20,
+        "lineNumber": 22,
         "ruleNames": [ "MD021", "no-multiple-space-closed-atx" ],
         "ruleDescription": "Multiple spaces inside hashes on closed atx style heading",
         "ruleInformation": "https://github.com/DavidAnson/markdownlint/blob/v0.0.0/doc/Rules.md#md021",
@@ -81,7 +90,7 @@
         "errorRange": [1, 5]
     },
     {
-        "lineNumber": 22,
+        "lineNumber": 24,
         "ruleNames": [ "MD021", "no-multiple-space-closed-atx" ],
         "ruleDescription": "Multiple spaces inside hashes on closed atx style heading",
         "ruleInformation": "https://github.com/DavidAnson/markdownlint/blob/v0.0.0/doc/Rules.md#md021",

test/long-lines-short-headings.json

@@ -0,0 +1,7 @@
+{
+  "default": true,
+  "MD003": false,
+  "MD013": {
+    "heading_line_length": 30
+  }
+}

test/long-lines-short-headings.md

@@ -0,0 +1,20 @@
+# Long Lines, Short Headings
+
+Text text text text text text text text text text text text text text text text text {MD013}
+
+## Short heading text text text
+
+Text
+
+## Long heading text text text {MD013}
+
+Text
+
+## Long heading text text {MD013} ##
+
+Text
+
+Long heading of text text text text text text {MD013}
+-----------------------------------------------------
+
+Text