Reimplement MD038/no-space-in-code to handle multi-backtick strings (fixes #46).

doc/Rules.md

@@ -986,6 +986,11 @@ To fix this, remove the spaces inside the codespan markers:
 
     `some text`
 
+Note: A single leading or trailing space is allowed if used to separate codespan
+markers from an embedded backtick:
+
+    `` ` embedded backtick``
+
 ## MD039 - Spaces inside link text
 
 Tags: whitespace, links

lib/rules.js

@@ -947,20 +947,19 @@ module.exports = [
     "aliases": [ "no-space-in-code" ],
     "regexp": spaceInsideCodeRe,
     "func": function MD038(params, errors) {
+      var inlineCodeSpansRe = /(`+)((?:.*?[^`])|)\1(?!`)/g;
       forEachInlineChild(params, "code_inline",
-        function forToken(token, inline) {
-          var backtickPairs = "^(?:[^`]*`[^`]*`)*[^`]*";
-          var escapedContent = escapeForRegExp(token.content);
-          var left = (new RegExp(
-              backtickPairs + "(`\\s+" + escapedContent + "\\s*`)"))
-            .exec(inline.content);
-          var right = (new RegExp(
-              backtickPairs + "(`\\s*" + escapedContent + "\\s+`)"))
-            .exec(inline.content);
-          if (left) {
-            errors.addContext(token.lineNumber, left[1]);
-          } else if (right) {
-            errors.addContext(token.lineNumber, right[1], false, true);
+        function forToken(token) {
+          var line = params.lines[token.lineNumber - 1];
+          var match = null;
+          while ((match = inlineCodeSpansRe.exec(line)) !== null) {
+            var inlineCodeSpan = match[0];
+            var content = match[2];
+            if (/^\s([^`]|$)/.test(content)) {
+              errors.addContext(token.lineNumber, inlineCodeSpan);
+            } else if (/[^`]\s$/.test(content)) {
+              errors.addContext(token.lineNumber, inlineCodeSpan, false, true);
+            }
           }
         });
     }

test/spaces_inside_codespan_elements.md

@@ -6,6 +6,10 @@
 
 ` codespan element with spaces inside ` {MD038}
 
+empty `` codespan element
+
+single space ` ` codespan element {MD038}
+
 `,`, `.`
 
 `,`, `code`
@@ -21,3 +25,33 @@ text `code` text `anything` code `end`
 text `anything` code `code` text `end`
 
 text `anything` text `anything` code `anything` `code`
+
+text ``code`` text ``code`` text
+
+text `` code`` text {MD038}
+
+text ``code `` text {MD038}
+
+text ```code``` text ```code``` text
+
+text ```code``` text `` code`` text {MD038}
+
+text ```code``` text ``code `` text {MD038}
+
+``embedded ` backtick`` text `code`
+
+`backslash does not escape \` backtick`
+
+`` ` `` text `code`
+
+` `` ` text `code`
+
+``` ` leading space allowed for backtick``` text `code`
+
+```  ` multiple leading spaces not allowed``` text `code` {MD038}
+
+``trailing space allowed for backtick ` `` text `code`
+
+``multiple trailing spaces not allowed `  `` text `code` {MD038}
+
+`` ` leading and trailing space allowed for backtick ` `` text `code`