✨ NEW: Add colon_fence plugin (#91)

Author: chrisjsewell

markdown_it/extensions/colon_fence.py

@@ -0,0 +1,132 @@
+from markdown_it import MarkdownIt
+from markdown_it.common.utils import unescapeAll, escapeHtml, stripEscape
+from markdown_it.rules_block import StateBlock
+
+
+def colon_fence_plugin(md: MarkdownIt):
+    """This plugin directly mimics regular fences, but with `:` colons.
+
+    Example::
+
+        :::name
+        contained text
+        :::
+
+    """
+
+    md.block.ruler.before(
+        "fence",
+        "colon_fence",
+        _rule,
+        {"alt": ["paragraph", "reference", "blockquote", "list", "footnote_def"]},
+    )
+    md.add_render_rule("colon_fence", _render)
+
+
+def _rule(state: StateBlock, startLine: int, endLine: int, silent: bool):
+
+    haveEndMarker = False
+    pos = state.bMarks[startLine] + state.tShift[startLine]
+    maximum = state.eMarks[startLine]
+
+    # if it's indented more than 3 spaces, it should be a code block
+    if state.sCount[startLine] - state.blkIndent >= 4:
+        return False
+
+    if pos + 3 > maximum:
+        return False
+
+    marker = state.srcCharCode[pos]
+
+    # /* : */
+    if marker != 0x3A:
+        return False
+
+    # scan marker length
+    mem = pos
+    pos = state.skipChars(pos, marker)
+
+    length = pos - mem
+
+    if length < 3:
+        return False
+
+    markup = state.src[mem:pos]
+    params = state.src[pos:maximum]
+
+    # Since start is found, we can report success here in validation mode
+    if silent:
+        return True
+
+    # search end of block
+    nextLine = startLine
+
+    while True:
+        nextLine += 1
+        if nextLine >= endLine:
+            # unclosed block should be autoclosed by end of document.
+            # also block seems to be autoclosed by end of parent
+            break
+
+        pos = mem = state.bMarks[nextLine] + state.tShift[nextLine]
+        maximum = state.eMarks[nextLine]
+
+        if pos < maximum and state.sCount[nextLine] < state.blkIndent:
+            # non-empty line with negative indent should stop the list:
+            # - ```
+            #  test
+            break
+
+        if state.srcCharCode[pos] != marker:
+            continue
+
+        if state.sCount[nextLine] - state.blkIndent >= 4:
+            # closing fence should be indented less than 4 spaces
+            continue
+
+        pos = state.skipChars(pos, marker)
+
+        # closing code fence must be at least as long as the opening one
+        if pos - mem < length:
+            continue
+
+        # make sure tail has spaces only
+        pos = state.skipSpaces(pos)
+
+        if pos < maximum:
+            continue
+
+        haveEndMarker = True
+        # found!
+        break
+
+    # If a fence has heading spaces, they should be removed from its inner block
+    length = state.sCount[startLine]
+
+    state.line = nextLine + (1 if haveEndMarker else 0)
+
+    token = state.push("colon_fence", "code", 0)
+    token.info = stripEscape(params)
+    token.content = state.getLines(startLine + 1, nextLine, length, True)
+    token.markup = markup
+    token.map = [startLine, state.line]
+
+    return True
+
+
+def _render(self, tokens, idx, options, env):
+    token = tokens[idx]
+    info = unescapeAll(token.info).strip() if token.info else ""
+    content = escapeHtml(token.content)
+    block_name = ""
+
+    if info:
+        block_name = info.split()[0]
+
+    return (
+        "<pre><code"
+        + (f' class="block-{block_name}" ' if block_name else "")
+        + ">"
+        + content
+        + "</code></pre>\n"
+    )