1 files changed, 67 insertions, 0 deletions
diff --git a/src/mistune/plugins/task_lists.py b/src/mistune/plugins/task_lists.py
new file mode 100644
index 0000000..8571c32
--- /dev/null
+++ b/src/mistune/plugins/task_lists.py
@@ -0,0 +1,67 @@
+import re
+
+__all__ = ['task_lists']
+
+
+TASK_LIST_ITEM = re.compile(r'^(\[[ xX]\])\s+')
+
+
+def task_lists_hook(md, state):
+    return _rewrite_all_list_items(state.tokens)
+
+
+def render_task_list_item(renderer, text, checked=False):
+    checkbox = (
+        '<input class="task-list-item-checkbox" '
+        'type="checkbox" disabled'
+    )
+    if checked:
+        checkbox += ' checked/>'
+    else:
+        checkbox += '/>'
+
+    if text.startswith('<p>'):
+        text = text.replace('<p>', '<p>' + checkbox, 1)
+    else:
+        text = checkbox + text
+
+    return '<li class="task-list-item">' + text + '</li>\n'
+
+
+def task_lists(md):
+    """A mistune plugin to support task lists. Spec defined by
+    GitHub flavored Markdown and commonly used by many parsers:
+
+    .. code-block:: text
+
+        - [ ] unchecked task
+        - [x] checked task
+
+    :param md: Markdown instance
+    """
+    md.before_render_hooks.append(task_lists_hook)
+    if md.renderer and md.renderer.NAME == 'html':
+        md.renderer.register('task_list_item', render_task_list_item)
+
+
+def _rewrite_all_list_items(tokens):
+    for tok in tokens:
+        if tok['type'] == 'list_item':
+            _rewrite_list_item(tok)
+        if 'children' in tok:
+            _rewrite_all_list_items(tok['children'])
+    return tokens
+
+
+def _rewrite_list_item(tok):
+    children = tok['children']
+    if children:
+        first_child = children[0]
+        text = first_child.get('text', '')
+        m = TASK_LIST_ITEM.match(text)
+        if m:
+            mark = m.group(1)
+            first_child['text'] = text[m.end():]
+
+            tok['type'] = 'task_list_item'
+            tok['attrs'] = {'checked': mark != '[ ]'}