1 files changed, 24 insertions, 7 deletions
diff --git a/lint b/lint
index 9bdcc57..d12431c 100755
--- a/lint
+++ b/lint
@@ -26,28 +26,45 @@ def run(cmd, file):
             print(msg)
 
 
-def find_files(bizroot, extensions):
-    "Return a dict of {ext: [files]} that we should lint."
-    ret = {k: [] for k in extensions}
-    changed = (
+def changed_files():
+    "Return a list of changed files according to git."
+    return (
         subprocess.check_output(["git", "diff", "--cached", "--name-only"])
         .decode("utf-8")
         .strip()
     )
+
+
+def group_files(files, extensions):
+    """Given a list of files and list of extensions, return a dict of:
+       {ext: [files]}
+
+    """
+    root = os.getenv("BIZ_ROOT")
+    ret = {k: [] for k in extensions}
     for ext in extensions:
-        for file in changed:
+        for file in files:
             if file.endswith(ext):
-                ret[ext].append(os.path.join(bizroot, file))
+                ret[ext].append(os.path.join(root, file))
     return ret
 
 
 if __name__ == "__main__":
     ERRORS = 0
-    FILES = find_files(os.getenv("BIZ_ROOT"), [".hs", ".py"])
+    if "-h" in sys.argv:
+        print(f"usage: {os.path.basename(__file__)} <files...>")
+        print("if no files given, lint files staged in git")
+        sys.exit(0)
+    elif len(sys.argv) == 1:
+        FILES = group_files(changed_files(), [".hs", ".py"])
+    else:
+        FILES = group_files(sys.argv[1:], [".hs", ".py"])
     for hs in FILES[".hs"]:
+        print(f"lint: {hs}")
         run("ormolu", hs)
         run("hlint", hs)
     for py in FILES[".py"]:
+        print(f"lint: {py}")
         run("black", py)
         run("pylint", py)
     run("black", __file__)