add lint.py for whitespace checking.

scripts/lint.py

@@ -0,0 +1,53 @@
+#!/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 sys
+import shlex
+import argparse
+import subprocess
+
+def trace(args):
+  print('$', *map(shlex.quote, args), file=sys.stderr)
+  return args
+
+def lint(args) -> int:
+  cmd = (
+    ['grep', '-Rn', r'\s$']
+    + [f'--include={f}' for f in args.include]
+    + [f'--exclude-dir={f}' for f in args.exclude_dir]
+  )
+
+  if not args.fix:
+    ret = subprocess.run(trace(cmd + args.files))
+    if ret.returncode == 0:
+      print("\nfound trailing whitespace in above files!")
+      return 1
+    else:
+      return 0
+  else:
+    cmd += ['-l', '--null']
+    ret = subprocess.run(trace(cmd + args.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
+
+def main():
+  argp = argparse.ArgumentParser(formatter_class=argparse.ArgumentDefaultsHelpFormatter)
+  argp.add_argument('--fix', action='store_true', help='remove trailing whitespace in-place')
+  argp.add_argument('--include', nargs='*', default=['*.ml', '*.mli', '*.cpp', '*.hpp'], help='grep file globs to include')
+  argp.add_argument('--exclude-dir', nargs='*', default=['_build', 'build'], help='grep directory globs to include')
+  argp.add_argument('files', nargs='*', default=['.'], help='directories to include')
+
+  args = argp.parse_intermixed_args()
+
+  sys.exit(lint(args))
+
+if __name__ == '__main__':
+  main()
+