👌 IMPROVE: MyST target block parsing (#31)

Match characters instead of using regex.
This now allows for an unlimited target length and whitespace in the target.
Also improve default rendering, inline with https://github.com/executablebooks/myst-vs-code

mdit_py_plugins/myst_blocks/index.py

@@ -1,12 +1,9 @@
 import itertools
-import re
 
 from markdown_it import MarkdownIt
 from markdown_it.common.utils import escapeHtml, isSpace
 from markdown_it.rules_block import StateBlock
 
-TARGET_PATTERN = re.compile(r"^\(([a-zA-Z0-9\|\@\<\>\*\.\/\_\-\+\:]{1,100})\)\=\s*$")
-
 
 def myst_block_plugin(md: MarkdownIt):
     """Parse MyST targets (``(name)=``), blockquotes (``% comment``) and block breaks (``+++``)."""
@@ -122,8 +119,12 @@ def target(state: StateBlock, startLine: int, endLine: int, silent: bool):
     if state.sCount[startLine] - state.blkIndent >= 4:
         return False
 
-    match = TARGET_PATTERN.match(state.src[pos:maximum])
-    if not match:
+    text = state.src[pos:maximum].strip()
+    if not text.startswith("("):
+        return False
+    if not text.endswith(")="):
+        return False
+    if not text[1:-2]:
         return False
 
     if silent:
@@ -133,17 +134,17 @@ def target(state: StateBlock, startLine: int, endLine: int, silent: bool):
 
     token = state.push("myst_target", "", 0)
     token.attrSet("class", "myst-target")
-    token.content = match.group(1)
+    token.content = text[1:-2]
     token.map = [startLine, state.line]
 
     return True
 
 
 def render_myst_target(self, tokens, idx, options, env):
-    content = tokens[idx].content
-    return (
-        '<div class="myst-target">' f"target = <code>{escapeHtml(content)}</code></div>"
-    )
+    label = tokens[idx].content
+    class_name = "myst-target"
+    target = f'<a href="#{label}">({label})=</a>'
+    return f'<div class="{class_name}">{target}</div>'
 
 
 def render_myst_line_comment(self, tokens, idx, options, env):

tests/fixtures/myst_block.md

@@ -41,32 +41,58 @@ a
 <hr class="myst-block">
 .
 
-
 Target:
 .
 (a)=
 .
-<div class="myst-target">target = <code>a</code></div>
+<div class="myst-target"><a href="#a">(a)=</a></div>
+.
+
+Target characters:
+.
+(a bc   |@<>*./_-+:)=
+.
+<div class="myst-target"><a href="#a bc   |@<>*./_-+:">(a bc   |@<>*./_-+:)=</a></div>
+.
+
+Empty target:
+.
+()=
+.
+<p>()=</p>
 .
 
+Escaped target:
+.
+\(a)=
+.
+<p>(a)=</p>
+.
+
+Indented target:
+.
+  (a)= 
+.
+<div class="myst-target"><a href="#a">(a)=</a></div>
+.
 
 Target terminates other blocks:
 .
 a
-(a)=
+(a-b)=
 - b
-(a)=
+(a b)=
 > c
 (a)=
 .
 <p>a</p>
-<div class="myst-target">target = <code>a</code></div><ul>
+<div class="myst-target"><a href="#a-b">(a-b)=</a></div><ul>
 <li>b</li>
 </ul>
-<div class="myst-target">target = <code>a</code></div><blockquote>
+<div class="myst-target"><a href="#a b">(a b)=</a></div><blockquote>
 <p>c</p>
 </blockquote>
-<div class="myst-target">target = <code>a</code></div>
+<div class="myst-target"><a href="#a">(a)=</a></div>
 .
 
 Comment: