new script to blacken docstrings in bindings

tools/black_bindings.py

@@ -0,0 +1,69 @@
+#!/usr/bin/python3
+from concurrent.futures import ThreadPoolExecutor
+import os
+import re
+import subprocess
+import sys
+
+
+def transform(fn, s):
+    lines = s.rstrip().split("\n")
+    lines = [line.removeprefix("//| ").removeprefix("//|") for line in lines]
+    while lines and not lines[0]:
+        del lines[0]
+
+    s = "\n".join(lines) + "\n"
+    if s[0] == " ":
+        prefix = "if 0:\n"
+    else:
+        prefix = ""
+    s = prefix + s
+    try:
+        # Line length is 95 so that with "//| " the max is 99
+        result = subprocess.run(
+            ["black", "--pyi", "-l95", "-q", "-"],
+            input=s,
+            check=True,
+            stdout=subprocess.PIPE,
+            encoding="utf-8",
+        )
+    except subprocess.CalledProcessError as e:
+        print(f"{fn}:0: Failed to process block:\n{s}")
+        raise
+
+    result = result.stdout[len(prefix) :].strip("\n")
+    result = (result.rstrip()).split("\n")
+    return "\n".join("//| " + line if line else "//|" for line in result) + "\n"
+
+
+def process_one_file(fn):
+    with open(fn, "r", encoding="utf-8") as f:
+        content = f.read()
+
+    old_end = 0
+
+    parts = []
+    for m in re.finditer("(?m)((?:^//\|.*\n)(?:^//\|.*\n)*)", content):
+        parts.append(content[old_end : m.start()])
+        parts.append(transform(fn, m.group()))
+        old_end = m.end()
+    parts.append(content[old_end:])
+    newcontent = "".join(parts)
+
+    if newcontent != content:
+        with open(fn, "w", encoding="utf-8") as f:
+            f.write(newcontent)
+
+
+if __name__ == "__main__":
+    # Use a thread pool because most processing is inside black!
+    executor = ThreadPoolExecutor(max_workers=os.cpu_count())
+    futures = [executor.submit(process_one_file, fn) for fn in sys.argv[1:]]
+    status = 0
+    for f in futures:
+        try:
+            f.result()
+        except Exception as e:
+            status = 1
+    executor.shutdown()
+    raise SystemExit(status)