Replace asserts with check.isinstance and simplify type hints and predicates

Update blockquote kind function to use PEP 604 union syntax, switch runtime type checks to omlish.check, streamline Unicode punctuation detection, and clarify the HTML block start loop condition.

Author: wrmsr

omxtra/text/pdcmark/blocks/machine.py

@@ -964,7 +964,7 @@ def _close_container_event(self, c: OpenContainer, end_offset: int) -> Event:
 }
 
 
-def _scan_blockquote_kind_consuming(ls: LineStart) -> 'BlockQuoteKind | None':
+def _scan_blockquote_kind_consuming(ls: LineStart) -> BlockQuoteKind | None:
     """
     Look at the remainder of the line for `[!NAME]` followed only by whitespace through EOL. On match, consume the
     marker text and return the kind. Otherwise leave `ls` unchanged.

omxtra/text/pdcmark/inlines/emphasis.py

@@ -9,6 +9,8 @@
 Cf. pulldown-cmark/src/parse.rs::{handle_emphasis_and_hard_break, InlineStack} — same algorithm. The pulldown version
 operates on its block tree in place; we operate on a fresh list.
 """
+from omlish import check
+
 from .nodes import DelimNode
 from .nodes import EmphasisGroup
 from .nodes import InlineNode
@@ -42,7 +44,7 @@ def resolve_emphasis(nodes: list[InlineNode]) -> list[InlineNode]:
             if match_s is not None:
                 opener_i = delim_stack[match_s]
                 opener = nodes[opener_i]
-                assert isinstance(opener, DelimNode)
+                check.isinstance(opener, DelimNode)
 
                 # GFM strikethrough: `~` and `~~` both produce <del>; longer runs (`~~~+`) don't pair at all. Equivalent
                 # to the GFM "tilde must be ≤ 2 chars" rule.

omxtra/text/pdcmark/inlines/links.py

@@ -14,6 +14,7 @@
   - Resolution order for a closer: inline → reference → collapsed → shortcut. Whichever first succeeds wins. None
     succeeded? The opener / closer revert to text.
 """
+from omlish import check
 from omlish import dataclasses as dc
 
 from ..blocks.refdefs import LinkDef
@@ -95,7 +96,7 @@ def resolve_links(
             match_s = len(stack) - 1
             entry = stack[match_s]
             opener = nodes[entry.node_index]
-            assert isinstance(opener, LinkOpenNode)
+            check.isinstance(opener, LinkOpenNode)
 
             # Inner children = nodes strictly between opener and closer.
             children = nodes[entry.node_index + 1:i]

omxtra/text/pdcmark/inlines/tokenize.py

@@ -398,7 +398,7 @@ def _is_unicode_punct(c: str) -> bool:
     if c in '!"#$%&\'()*+,-./:;<=>?@[\\]^_`{|}~':
         return True
     cat = unicodedata.category(c)
-    return cat.startswith('P') or cat.startswith('S')
+    return cat.startswith(('P', 'S'))
 
 
 def _line_index_at_newline(joined: _Joined, pos: int) -> int | None:

omxtra/text/pdcmark/scanning/htmlblocks.py

@@ -143,7 +143,7 @@ def scan_html_block_start(line: str) -> HtmlBlockStart | None:
     if is_close:
         i += 1
     j = i
-    while j < n and (line[j].isalnum() and line[j].isascii() or (j > i and line[j] in '0123456789')):
+    while j < n and ((line[j].isalnum() and line[j].isascii()) or (j > i and line[j] in '0123456789')):
         j += 1
     if j == i:
         return None