1 files changed, 97 insertions, 0 deletions
diff --git a/tools/check-exercises.py b/tools/check-exercises.py
new file mode 100755
index 0000000..fa0b5cb
--- /dev/null
+++ b/tools/check-exercises.py
@@ -0,0 +1,97 @@
+#!/usr/bin/env python
+
+import difflib
+import io
+import os
+import os.path
+import subprocess
+import sys
+
+
+IGNORE = subprocess.DEVNULL
+PIPE = subprocess.PIPE
+
+EXERCISES_PATH = "exercises"
+HEALED_PATH = "patches/healed"
+PATCHES_PATH = "patches/patches"
+
+
+# Heals all the exercises.
+def heal():
+    maketree(HEALED_PATH)
+
+    with os.scandir(EXERCISES_PATH) as it:
+        for entry in it:
+            name = entry.name
+
+            original_path = entry.path
+            patch_path = os.path.join(PATCHES_PATH, patch_name(name))
+            output_path = os.path.join(HEALED_PATH, name)
+
+            patch(original_path, patch_path, output_path)
+
+
+# Yields all the healed exercises that are not correctly formatted.
+def check_healed():
+    term = subprocess.run(
+        ["zig", "fmt", "--check", HEALED_PATH], stdout=PIPE, text=True
+    )
+    if term.stdout == "" and term.returncode != 0:
+        term.check_returncode()
+
+    stream = io.StringIO(term.stdout)
+    for line in stream:
+        yield line.strip()
+
+
+def main():
+    heal()
+
+    # Show the unified diff between the original example and the correctly
+    # formatted one.
+    for i, original in enumerate(check_healed()):
+        if i > 0:
+            print()
+
+        name = os.path.basename(original)
+        print(f"checking exercise {name}...\n")
+
+        from_file = open(original)
+        to_file = zig_fmt_file(original)
+
+        diff = difflib.unified_diff(
+            from_file.readlines(), to_file.readlines(), name, name + "-fmt"
+        )
+        sys.stderr.writelines(diff)
+
+
+def maketree(path):
+    return os.makedirs(path, exist_ok=True)
+
+
+# Returns path with the patch extension.
+def patch_name(path):
+    name, _ = os.path.splitext(path)
+
+    return name + ".patch"
+
+
+# Applies patch to original, and write the file to output.
+def patch(original, patch, output):
+    subprocess.run(
+        ["patch", "-i", patch, "-o", output, original], stdout=IGNORE, check=True
+    )
+
+
+# Formats the Zig file at path, and returns the possibly reformatted file as a
+# file object.
+def zig_fmt_file(path):
+    with open(path) as stdin:
+        term = subprocess.run(
+            ["zig", "fmt", "--stdin"], stdin=stdin, stdout=PIPE, check=True, text=True
+        )
+
+        return io.StringIO(term.stdout)
+
+
+main()