Add argument parsing to main module

boggler/__main__.py

@@ -1,24 +1,35 @@
 """Boggler Demo"""
+import argparse
 import sys
 from pathlib import Path
 from .boggler_utils import BoggleBoard, build_full_boggle_tree, read_boggle_file
 
-def main():
-    if len(sys.argv) < 3 or len(sys.argv) > 4:
-        print('Usage: python3 boggler.py <BOARD_FILE> <WORDLISTS_DIR> [MAX_WORD_LENGTH]')
-        sys.exit(1)
+parser = argparse.ArgumentParser(
+    prog="boggler",
+    description="Boggle board game solver"
+)
 
-    board = read_boggle_file(Path(sys.argv[1]))
-    if len(sys.argv) == 3:
-        boggle_board = BoggleBoard(board)
-    elif len(sys.argv) == 4:
+parser.add_argument("board", type=Path, help="Path to board CSV file")
+parser.add_argument("wordlists", type=Path,
+    help="Path to directory of wordlist files. The directory must contain \
+        text files of the form words_X.txt where \"X\" is a character of \
+        the alphabet")
+parser.add_argument("max_word_length", nargs="?", type=int, default=16,
+    help="Maximum length of words searched for on provided board")
+
+args = parser.parse_args()
+
+def main():
+    """Command line tool for sovling Boggle boards"""
+    board = read_boggle_file(args.board)
     try:
-            boggle_board = BoggleBoard(board, int(sys.argv[3]))
+        boggle_board = BoggleBoard(board, args.max_word_length)
     except ValueError:
         print("Invalid MAX_WORD_LENGTH. Please try again with a valid integer.")
-            sys.exit(1)
+        sys.exit()
+
     try:
-        boggle_tree = build_full_boggle_tree(boggle_board, Path(sys.argv[2]))
+        boggle_tree = build_full_boggle_tree(boggle_board, args.wordlists)
 
         print("\nBOARD")
         print(boggle_board)
@@ -28,7 +39,7 @@ def main():
             for word in tree.word_paths:
                 print(f"{word[0]: <{boggle_board.max_word_len}}: {word[1]}")
 
-    except ValueError as e:
+    except ValueError:
         print("The [MAX_WORD_LENGTH] argument must be an integer.")
         print("Please try again.")
         sys.exit(1)