Allow multiline setext headers

lib/rules_block/lheading.js

@@ -4,42 +4,67 @@
 
 
 module.exports = function lheading(state, startLine, endLine/*, silent*/) {
-  var marker, pos, max, token, level,
-      next = startLine + 1;
-
-  if (next >= endLine) { return false; }
-  if (state.sCount[next] < state.blkIndent) { return false; }
-
-  // Scan next line
-
-  if (state.sCount[next] - state.blkIndent > 3) { return false; }
-
-  pos = state.bMarks[next] + state.tShift[next];
-  max = state.eMarks[next];
-
-  if (pos >= max) { return false; }
-
+  var content, terminate, i, l, token, pos, max, level, marker,
+      nextLine = startLine + 1,
+      terminatorRules = state.md.block.ruler.getRules('paragraph');
+
+  // jump line-by-line until empty one or EOF
+  for (; nextLine < endLine && !state.isEmpty(nextLine); nextLine++) {
+    // this would be a code block normally, but after paragraph
+    // it's considered a lazy continuation regardless of what's there
+    if (state.sCount[nextLine] - state.blkIndent > 3) { continue; }
+
+    //
+    // Check for underline in setext header
+    //
+    if (state.sCount[nextLine] >= state.blkIndent) {
+      pos = state.bMarks[nextLine] + state.tShift[nextLine];
+      max = state.eMarks[nextLine];
+
+      if (pos < max) {
         marker = state.src.charCodeAt(pos);
 
-  if (marker !== 0x2D/* - */ && marker !== 0x3D/* = */) { return false; }
-
+        if (marker === 0x2D/* - */ || marker === 0x3D/* = */) {
           pos = state.skipChars(pos, marker);
-
           pos = state.skipSpaces(pos);
 
-  if (pos < max) { return false; }
-
-  pos = state.bMarks[startLine] + state.tShift[startLine];
-
-  state.line = next + 1;
+          if (pos >= max) {
             level = (marker === 0x3D/* = */ ? 1 : 2);
+            break;
+          }
+        }
+      }
+    }
+
+    // quirk for blockquotes, this line should already be checked by that rule
+    if (state.sCount[nextLine] < 0) { continue; }
+
+    // Some tags can terminate paragraph without empty line.
+    terminate = false;
+    for (i = 0, l = terminatorRules.length; i < l; i++) {
+      if (terminatorRules[i](state, nextLine, endLine, true)) {
+        terminate = true;
+        break;
+      }
+    }
+    if (terminate) { break; }
+  }
+
+  if (!level) {
+    // Didn't find valid underline
+    return false;
+  }
+
+  content = state.getLines(startLine, nextLine, state.blkIndent, false).trim();
+
+  state.line = nextLine + 1;
 
   token          = state.push('heading_open', 'h' + String(level), 1);
   token.markup   = String.fromCharCode(marker);
   token.map      = [ startLine, state.line ];
 
   token          = state.push('inline', '', 0);
-  token.content  = state.src.slice(pos, state.eMarks[startLine]).trim();
+  token.content  = content;
   token.map      = [ startLine, state.line - 1 ];
   token.children = [];
 

test/fixtures/commonmark/bad.txt

@@ -1,41 +1,3 @@
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-src line: 877
-
-.
-Foo *bar
-baz*
-====
-.
-<h1>Foo <em>bar
-baz</em></h1>
-.
-
-error:
-
-<p>Foo <em>bar
-baz</em>
-====</p>
-
-
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-src line: 1057
-
-.
-Foo
-Bar
----
-.
-<h2>Foo
-Bar</h2>
-.
-
-error:
-
-<p>Foo
-Bar</p>
-<hr />
-
-
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 src line: 3777
 

test/fixtures/commonmark/good.txt

@@ -528,6 +528,18 @@ Foo *bar*
 <h2>Foo <em>bar</em></h2>
 .
 
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+src line: 877
+
+.
+Foo *bar
+baz*
+====
+.
+<h1>Foo <em>bar
+baz</em></h1>
+.
+
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 src line: 889
 
@@ -694,6 +706,18 @@ src line: 1042
 <hr />
 .
 
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+src line: 1057
+
+.
+Foo
+Bar
+---
+.
+<h2>Foo
+Bar</h2>
+.
+
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 src line: 1070
 

test/fixtures/markdown-it/commonmark_extras.txt

@@ -108,6 +108,32 @@ test
 </code></pre>
 .
 
+Setext header text supports lazy continuations:
+.
+ - foo
+bar
+   ===
+.
+<ul>
+<li>
+<h1>foo
+bar</h1>
+</li>
+</ul>
+.
+
+But setext header underline doesn't:
+.
+ - foo
+   bar
+  ===
+.
+<ul>
+<li>foo
+bar
+===</li>
+</ul>
+.
 
 Coverage. Directive can terminate paragraph.
 .