add linter for whitespace checking

scripts/lint.py

@@ -0,0 +1,77 @@
+#!/usr/bin/env python3
+# vim: set ts=2 sts=2 sw=2 et :
+
+# a simple linter to detect and remove trailing whitespace in OCaml files.
+
+import os
+import sys
+import shlex
+import argparse
+import subprocess
+
+from pathlib import Path
+
+def trace(args):
+  print('$', *map(shlex.quote, map(str, args)), file=sys.stderr)
+  return args
+
+def concat(xss):
+  return [x for xs in xss for x in xs]
+
+def lint(args) -> int:
+  cmd = (
+    ['git']
+    + ['-c', 'color.grep.matchSelected=white red', '-c', 'color.grep.function=yellow']
+    + ['grep', '-n', '--show-function', '--break', '--no-recursive']
+  )
+  cmd_files = (
+    # ['-l', '-e', r'', '--']
+    ['-e', r'\s\+$', '--']
+    # non-directories should be added literally
+    + [f for f in args.files if not f.is_dir()]
+    # directories are searched for files matching the includes.
+    # NOTE: include pattern might not begin with * so we must add an extra * to recurse
+    + [f'{d}/{i}' for d in args.files for i in args.include if d.is_dir()]
+    + [f'{d}/*/{i}' for d in args.files for i in args.include if d.is_dir() if not i.startswith('*')]
+  )
+
+  if args.fix:
+    cmd += ['-l', '--null']
+    ret = subprocess.run(trace(cmd + cmd_files), stdout=subprocess.PIPE)
+    files = [x.decode('utf-8') for x in ret.stdout.split(b'\0') if x]
+    print('files to fix:', files)
+    print()
+
+    if files:
+      return subprocess.call(trace(['sed', '-i', r's/\s\+$//g'] + files))
+    return 0
+  else:
+    if args.list:
+      cmd += ['-l']
+    ret = subprocess.run(trace(cmd + cmd_files))
+    if ret.returncode == 0:
+      print("\nfound trailing whitespace in above files!")
+      return 1
+    else:
+      return 0
+
+
+def main():
+  argp = argparse.ArgumentParser(formatter_class=argparse.ArgumentDefaultsHelpFormatter)
+  g = argp.add_mutually_exclusive_group()
+  g.add_argument('--check', action='store_true', default=True, help='check for trailing whitespace and print lines')
+  g.add_argument('--fix', action='store_true', help='remove trailing whitespace in-place')
+  g.add_argument('--list', action='store_true', help='list files with trailing whitespace')
+  argp.add_argument('--include', nargs='*', default=['dune', '*.ml', '*.mli', '*.cpp', '*.hpp', '*.scala'], help='grep file globs to include')
+  argp.add_argument('--untracked', action='store_true', help='include untracked files')
+  # argp.add_argument('--exclude-dir', nargs='*', default=['_build', 'build', 'target', 'out', '.git'], help='grep directory globs to include')
+  argp.add_argument('files', nargs='*', default=[Path('.')], type=Path, help='files or directories to include')
+
+  args = argp.parse_intermixed_args()
+  args.check = not (args.fix or args.list)
+
+  sys.exit(lint(args))
+
+if __name__ == '__main__':
+  main()
+