fix(headings): disallow whitespace before heading #22

Author: justinmk

corpus/heading1_2.txt

@@ -71,6 +71,12 @@ Text
 NOT h1 h2 heading
 ================================================================================
 
+ ===============================================================================
+must-start-at-column-1
+
+ ===============================================================================
+ must-start-at-column-1
+
 ====
 Not-a-heading-1                                                     *heading1*
 
@@ -93,6 +99,16 @@ Text
 --------------------------------------------------------------------------------
 
 (help_file
+  (block
+    (line
+      (word))
+    (line
+      (word)))
+  (block
+    (line
+      (word))
+    (line
+      (word)))
   (block
     (line
       (word))

grammar.js

@@ -97,15 +97,15 @@ module.exports = grammar({
 
     h1: ($) =>
       seq(
-        field('delimiter', /[\t ]*============+[\t ]*\n/),
+        token.immediate(field('delimiter', /============+[\t ]*\n/)),
         repeat1($._atom),
         '\n',
         repeat(_blank()),
       ),
 
     h2: ($) =>
       seq(
-        field('delimiter', /[\t ]*------------+[\t ]*\n/),
+        token.immediate(field('delimiter', /------------+[\t ]*\n/)),
         repeat1($._atom),
         '\n',
         repeat(_blank()),

src/grammar.json

@@ -532,11 +532,14 @@
       "type": "SEQ",
       "members": [
         {
-          "type": "FIELD",
-          "name": "delimiter",
+          "type": "IMMEDIATE_TOKEN",
           "content": {
-            "type": "PATTERN",
-            "value": "[\\t ]*============+[\\t ]*\\n"
+            "type": "FIELD",
+            "name": "delimiter",
+            "content": {
+              "type": "PATTERN",
+              "value": "============+[\\t ]*\\n"
+            }
           }
         },
         {
@@ -567,11 +570,14 @@
       "type": "SEQ",
       "members": [
         {
-          "type": "FIELD",
-          "name": "delimiter",
+          "type": "IMMEDIATE_TOKEN",
           "content": {
-            "type": "PATTERN",
-            "value": "[\\t ]*------------+[\\t ]*\\n"
+            "type": "FIELD",
+            "name": "delimiter",
+            "content": {
+              "type": "PATTERN",
+              "value": "------------+[\\t ]*\\n"
+            }
           }
         },
         {