replace -n/-b flags with Numbering Enum

Author: Luke-Manyamazi

implement-shell-tools/cat/cat.py

@@ -1,17 +1,23 @@
 import glob
 import argparse
+from enum import Enum
 
-def cat(filepath, n=False, b=False, line_counter=None):
+class Numbering(Enum):
+    NONE = 0
+    ALL = 1
+    NONEMPTY = 2
+
+def cat(filepath, numbering=Numbering.NONE, line_counter=None):
     try:
         with open(filepath) as f:
             for line in f:
-                if b:
+                if numbering == Numbering.NONEMPTY:
                     if line.strip():
                         print(f"{line_counter[0]:6}\t{line}", end='')
                         line_counter[0] += 1
                     else:
                         print(line, end='')
-                elif n:
+                elif numbering == Numbering.ALL:
                     print(f"{line_counter[0]:6}\t{line}", end='')
                     line_counter[0] += 1
                 else:
@@ -20,7 +26,7 @@ def cat(filepath, n=False, b=False, line_counter=None):
         print(f"cat: {filepath}: No such file or directory")
 
 def main():
-    parser = argparse.ArgumentParser(description = "Concatenate files and print on the standard output.")
+    parser = argparse.ArgumentParser(description="Concatenate files and print on the standard output.")
     parser.add_argument('-n', action='store_true', help='number all output lines')
     parser.add_argument('-b', action='store_true', help='number non-empty output lines')
     parser.add_argument('files', nargs='+', help='files to concatenate')
@@ -31,8 +37,19 @@ def main():
         files.extend(glob.glob(pattern) or [pattern])
 
     line_counter = [1]
+
+    # Determine numbering mode (mutually exclusive)
+    if args.n and args.b:
+        parser.error("options -n and -b are mutually exclusive")
+    elif args.n:
+        numbering = Numbering.ALL
+    elif args.b:
+        numbering = Numbering.NONEMPTY
+    else:
+        numbering = Numbering.NONE
+
     for file in sorted(files):
-        cat(file, args.n, args.b, line_counter)
+        cat(file, numbering=numbering, line_counter=line_counter)
 
 if __name__ == "__main__":
-    main()
+    main()