debug_regex.py

import re

content = """
  Blockly.Blocks['ui_section'] = {
    init: function() {
      // ...
      this.setPreviousStatement(true, "basic_body_element");
    }
  };
"""

# Pattern 1: Original (Suspected broken)
p1 = re.compile(r"\.setPreviousStatement\s*\(\s*true(?:,\s*(?:\[(.*?)\]|[\"\'](.*?)\"\']))?\s*\)", re.DOTALL)

# Pattern 2: Simplified
p2 = re.compile(r"\.setPreviousStatement\s*\(\s*true(?:,\s*(?:\[(.*?)\]|[\"'](.*?)[\"']))?\s*\)", re.DOTALL)

# Pattern 3: Very Simple
p3 = re.compile(r"\.setPreviousStatement\s*\(\s*true\s*,\s*[\"'](.*?)[\"']", re.DOTALL)

def test(name, pattern, text):
    m = pattern.search(text)
    if m:
        print(f"{name}: MATCH! Groups: {m.groups()}")
    else:
        print(f"{name}: NO MATCH")

print("--- Testing ui_section ---")
test("Pattern 1", p1, content)
test("Pattern 2", p2, content)
test("Pattern 3", p3, content)