Better argument parsing, added -n/--number option (from cat)

pat.py

@@ -1,39 +1,54 @@
 #!/usr/bin/env python3
 from enum import IntEnum
-from sys import argv, stdin, stderr
+from sys import stdin, stderr
 from string import whitespace
-
+import argparse
-# These next 2 lines of code are only for ANSI escape support on Windows cmd/powershell
+import os
-# If you do not use cmd/ps, you can comment them out or remove them
-from os import system
-
-system("")
-
-# If the program is using too much memory, try decreasing this value
-bytes_to_read = 1000000
-
 
 class ColorInfo(IntEnum):
-    AMOUNT = 299
+    AMOUNT = 299 # Amount of colors to be outputted (must not be higher than PER_STAGE)
-    MAX_RGB_VALUE = 255
+    MAX_RGB_VALUE = 255 # Max value any r/g/b can have
+    # Do not change these next 2
     PER_STAGE = (AMOUNT + 1) // 3
     MIN_RGB_VALUE = MAX_RGB_VALUE - PER_STAGE
 
+# If the program is using too much memory, try decreasing this value
+# If some text is getting cut off, try increasing this value
+bytes_to_read = 1000000
 
-if len(argv) == 1:
+first_file = True
-    argv.append("-")
 
-for arg in argv[1:]:
+line_str = lambda line: str(line).rjust(8, ' ') + ' '
+color_print = lambda red, green, blue, string: print(
+        "\x1b[38;2;%d;%d;%dm%s" % (red, green, blue, string),
+        end='')
+
+parser = argparse.ArgumentParser(description="Output text from files with color.")
+parser.add_argument(
+        "paths",
+        type=str,
+        nargs='*',
+        help="a path to open ('-' for stdin)",
+        default=['-'])
+parser.add_argument(
+        "-n", "--number",
+        help="number all output lines",
+        action="store_true")
+args = parser.parse_args()
+
+
+line = 1 if args.number else False
+
+# Windows command prompt / powershell support
+if os.name == "nt":
+    os.system('')
+
+for path in args.paths:
     try:
-        file = stdin if arg == "-" else open(arg, "r")
+        file = stdin if path == '-' else open(path, 'r')
         read_result = file.read(bytes_to_read)
     except Exception as e:
-        print(
+        print(f"Error reading {path}: {e}", file=stderr)
-            "Error "
-            + (f"reading {file.name}" if "file" in globals() else "opening file")
-            + f": {e}",
-            file=stderr,
-        )
         continue
 
     changes = len(list(filter(lambda c: not c in whitespace, read_result))) - 1
@@ -41,9 +56,20 @@ for arg in argv[1:]:
     step = 0 if changes == 0 else ColorInfo.AMOUNT / changes
     index = 0
 
+    if line and first_file:
+        color_print(
+                ColorInfo.MAX_RGB_VALUE,
+                ColorInfo.MIN_RGB_VALUE,
+                ColorInfo.MIN_RGB_VALUE,
+                line_str(line))
+
+
     for char in read_result:
         if char in whitespace:
-            print(char, end="")
+            print(char, end='')
+            if line and char == '\n':
+                line += 1
+                print(line_str(line), end='')
             continue
 
         color_value = round(index)
@@ -59,7 +85,6 @@ for arg in argv[1:]:
             [rgb_values[0], rgb_values[2], rgb_values[1]],
         ][color_value // ColorInfo.PER_STAGE]
 
-        print("\x1b[38;2;%d;%d;%dm%s" % (red, green, blue, char), end="")
+        color_print(red, green, blue, char)
         index += step
-
 print("\x1b[0m")