feat(wc): add Python implementation with full flag support

- Implement wc/wc.py: Python version of wc utility
- Support -l/--lines, -w/--words, -c/--bytes flags
- Read from stdin when no files provided
- Process multiple files with totals row
- Calculate byte counts using raw file bytes for accuracy
- Format output with right-justified columns (4-char width)
- Handle file not found errors with proper exit codes
- Match behavior of JavaScript implementation
- Add argparse for robust CLI argument parsing

Author: Iswanna

implement-shell-tools/wc/wc.py

@@ -0,0 +1,98 @@
+import argparse
+import sys
+import os
+
+
+def calculate_stats(content, display_name, original_bytes=None):
+    lines = content.count("\n")
+    words = len(content.split())
+    # If we have the raw bytes, use that length. Otherwise, encode to get byte length.
+    byte_count = (
+        original_bytes if original_bytes is not None else len(content.encode("utf-8"))
+    )
+
+    return {
+        "lineCount": lines,
+        "wordCount": words,
+        "byteCount": byte_count,
+        "displayName": display_name,
+    }
+
+
+def print_formatted_report(stats, args, should_show_all_stats):
+    output_columns = []
+
+    def format_col(count):
+        return str(count).rjust(4)
+
+    if should_show_all_stats:
+        output_columns.append(format_col(stats["lineCount"]))
+        output_columns.append(format_col(stats["wordCount"]))
+        output_columns.append(format_col(stats["byteCount"]))
+    else:
+        if args.lines:
+            output_columns.append(format_col(stats["lineCount"]))
+        if args.words:
+            output_columns.append(format_col(stats["wordCount"]))
+        if args.bytes:
+            output_columns.append(format_col(stats["byteCount"]))
+
+    # Use a single space between the numbers and the name
+    print(f"{''.join(output_columns)} {stats['displayName']}")
+
+
+def main():
+    parser = argparse.ArgumentParser(description="A simple Python implementation of wc")
+    parser.add_argument("files", nargs="*", help="Files to process")
+    parser.add_argument(
+        "-l", "--lines", action="store_true", help="print the newline counts"
+    )
+    parser.add_argument(
+        "-w", "--words", action="store_true", help="print the word counts"
+    )
+    parser.add_argument(
+        "-c", "--bytes", action="store_true", help="print the byte counts"
+    )
+
+    args = parser.parse_args()
+    should_show_all_stats = not (args.lines or args.words or args.bytes)
+    all_file_stats = []
+    exit_code = 0
+
+    # NEW: Handle Standard Input if no files are provided
+    if not args.files:
+        stdin_content = sys.stdin.read()
+        stats = calculate_stats(stdin_content, "")
+        print_formatted_report(stats, args, should_show_all_stats)
+        return
+
+    # Process files
+    for file_path in args.files:
+        try:
+            with open(file_path, "rb") as f:
+                raw_bytes = f.read()
+                content = raw_bytes.decode("utf-8", errors="ignore")
+                stats = calculate_stats(content, file_path, len(raw_bytes))
+
+            all_file_stats.append(stats)
+            print_formatted_report(stats, args, should_show_all_stats)
+        except Exception:
+            print(f"wc: {file_path}: No such file or directory", file=sys.stderr)
+            exit_code = 1
+
+    # Print total if more than one file
+    if len(all_file_stats) > 1:
+        grand_totals = {
+            "lineCount": sum(s["lineCount"] for s in all_file_stats),
+            "wordCount": sum(s["wordCount"] for s in all_file_stats),
+            "byteCount": sum(s["byteCount"] for s in all_file_stats),
+            "displayName": "total",
+        }
+        print_formatted_report(grand_totals, args, should_show_all_stats)
+
+    if exit_code != 0:
+        sys.exit(exit_code)
+
+
+if __name__ == "__main__":
+    main()