forge: DRY collapse duplicate fence-tracking in queue_index.parse

tools/queue_index.py

@@ -195,19 +195,34 @@ def status_value(raw):
     return raw
 
 
+def fence_mask(lines):
+    """1-based line numbers to skip: fence delimiters and every line they hide.
+
+    A fenced block is quoted material, not document structure -- headings inside
+    it are not sections, and id tokens inside it are not records. Stated once
+    here and reused by parse(), rather than restated verbatim in each scan loop.
+    """
+    out = set()
+    in_fence = False
+    for i, ln in enumerate(lines, 1):
+        if FENCE.match(ln.strip()):
+            in_fence = not in_fence
+            out.add(i)
+        elif in_fence:
+            out.add(i)
+    return out
+
+
 def parse(text):
     """Return the structural parse: sections, nested ids, id map, byte accounting."""
     lines, trailing_newline = split_lines(text)
     n = len(lines)
     sizes = [line_bytes(ln, i == n - 1, trailing_newline) for i, ln in enumerate(lines)]
+    fenced = fence_mask(lines)
 
     headings = []           # (line_no, id, rest)
-    in_fence = False
     for i, ln in enumerate(lines, 1):
-        if FENCE.match(ln.strip()):
-            in_fence = not in_fence
-            continue
-        if in_fence:
+        if i in fenced:
             continue
         m = HEADING.match(ln)
         if m:
@@ -261,12 +276,8 @@ def parse(text):
     # (Q54/Q55/Q56/Q58 as artifact filenames, Q62 inside `Q31-Q62`, Q77/Q99 inside
     # a quoted `--outside` list) is not an item at all.
     mentioned = {}
-    in_fence = False
     for i, ln in enumerate(lines, 1):
-        if FENCE.match(ln.strip()):
-            in_fence = not in_fence
-            continue
-        if in_fence:
+        if i in fenced:
             continue
         for m in ID_TOKEN.finditer(ln):
             qid = m.group(0)