Allow selecting and printing puzzles from the library to the command line

puzzles.py

@@ -4,31 +4,54 @@
 Parser for puzzles in the ./puzzles directory.
 '''
 
+import argparse
 import sudoku
+import sys
 
 euler = []
 norvig = []
 
-def parse_puzzle_files():
+def parse_puzzle_files(quiet=True):
     global euler, norvig
 
+    if not quiet:
         print('Parsing Euler puzzles')
-    euler = list(_get_puzzles('puzzles/euler.txt'))
+    euler.extend(_get_puzzles('puzzles/euler.txt', quiet))
 
+    if not quiet:
         print('Parsing Norvig puzzles')
-    norvig = list(_get_puzzles('puzzles/norvig.txt'))
+    norvig.extend(_get_puzzles('puzzles/norvig.txt', quiet))
 
-def _get_puzzles(filename):
+def _get_puzzles(filename, quiet):
     with open(filename, 'r') as f:
         puzzles = f.readlines()
-    return (_parse_puzzle(p) for p in puzzles if p)
+    return (_parse_puzzle(p, quiet) for p in puzzles if p)
 
-def _parse_puzzle(puzzle):
+def _parse_puzzle(puzzle, quiet):
     puzzle = puzzle.strip()
     if len(puzzle) == 81:
+        if not quiet:
             print("Parsing  '{}'".format(puzzle))
         board = (int('0' if x == '.' else x) for x in puzzle)
         return sudoku.Sudoku(board=board)
     else:
+        if not quiet:
             print("Skipping '{}'".format(puzzle))
         return None
+
+def parse_args(args):
+    parser = argparse.ArgumentParser()
+    parser.add_argument('--euler', '-e', dest='library', action='store_const', const=euler, default=None)
+    parser.add_argument('--norvig', '-n', dest='library', action='store_const', const=norvig, default=None)
+    parser.add_argument('--verbose', '-v', action='store_true', default=False)
+    parser.add_argument('index', default=0, type=int)
+    return parser.parse_args(args)
+
+def main():
+    args = parse_args(sys.argv[1:])
+    parse_puzzle_files(quiet=not args.verbose)
+    print(args.library[args.index])
+    return 0
+
+if __name__ == '__main__':
+    sys.exit(main())