+import unittest
+from functools import partial
+
+
+class ArgError(Exception):
+ pass
+
+
+class Parser:
+
+ def __init__(self, game=None):
+ self.game = game
+
+ def tokenize(self, msg):
+ """Parse msg string into tokens.
+
+ Separates by ' ' and '\n', but allows whitespace in tokens quoted by
+ '"', and allows escaping within quoted tokens by a prefixed backslash.
+ """
+ tokens = []
+ token = ''
+ quoted = False
+ escaped = False
+ for c in msg:
+ if quoted:
+ if escaped:
+ token += c
+ escaped = False
+ elif c == '\\':
+ escaped = True
+ elif c == '"':
+ quoted = False
+ else:
+ token += c
+ elif c == '"':
+ quoted = True
+ elif c in {' ', '\n'}:
+ if len(token) > 0:
+ tokens += [token]
+ token = ''
+ else:
+ token += c
+ if len(token) > 0:
+ tokens += [token]
+ return tokens
+
+ def parse(self, msg):
+ """Parse msg as call to self.game method, return method with arguments.
+
+ Respects method signatures defined in methods' .argtypes attributes.
+ """
+ tokens = self.tokenize(msg)
+ if len(tokens) == 0:
+ return None
+ method_candidate = 'cmd_' + tokens[0]
+ if not hasattr(self.game, method_candidate):
+ return None
+ method = getattr(self.game, method_candidate)
+ if len(tokens) == 1:
+ if not hasattr(method, 'argtypes'):
+ return method
+ else:
+ raise ArgError('Command expects argument(s).')
+ args_candidates = tokens[1:]
+ if not hasattr(method, 'argtypes'):
+ raise ArgError('Command expects no argument(s).')
+ args, kwargs = self.argsparse(method.argtypes, args_candidates)
+ return partial(method, *args, **kwargs)
+
+ def parse_yx_tuple(self, yx_string):
+ """Parse yx_string as yx_tuple:nonneg argtype, return result."""
+
+ def get_axis_position_from_argument(axis, token):
+ if len(token) < 3 or token[:2] != axis + ':' or \
+ not token[2:].isdigit():
+ raise ArgError('Non-int arg for ' + axis + ' position.')
+ n = int(token[2:])
+ if n < 1:
+ raise ArgError('Arg for ' + axis + ' position < 1.')
+ return n
+
+ tokens = yx_string.split(',')
+ if len(tokens) != 2:
+ raise ArgError('Wrong number of yx-tuple arguments.')
+ y = get_axis_position_from_argument('Y', tokens[0])
+ x = get_axis_position_from_argument('X', tokens[1])
+ return (y, x)
+
+ def argsparse(self, signature, args_tokens):
+ """Parse into / return args_tokens as args/kwargs defined by signature.
+
+ Expects signature to be a ' '-delimited sequence of any of the strings
+ 'int:nonneg', 'yx_tuple:nonneg', 'string', 'seq:int:nonneg', defining
+ the respective argument types.
+ """
+ tmpl_tokens = signature.split()
+ if len(tmpl_tokens) != len(args_tokens):
+ raise ArgError('Number of arguments (' + str(len(args_tokens)) +
+ ') not expected number (' + str(len(tmpl_tokens))
+ + ').')
+ args = []
+ for i in range(len(tmpl_tokens)):
+ tmpl = tmpl_tokens[i]
+ arg = args_tokens[i]
+ if tmpl == 'int:nonneg':
+ if not arg.isdigit():
+ raise ArgError('Argument must be non-negative integer.')
+ args += [int(arg)]
+ elif tmpl == 'yx_tuple:nonneg':
+ args += [self.parse_yx_tuple(arg)]
+ elif tmpl == 'string':
+ args += [arg]
+ elif tmpl == 'seq:int:nonneg':
+ sub_tokens = arg.split(',')
+ if len(sub_tokens) < 1:
+ raise ArgError('Argument must be non-empty sequence.')
+ seq = []
+ for tok in sub_tokens:
+ if not tok.isdigit():
+ raise ArgError('Argument sequence must only contain '
+ 'non-negative integers.')
+ seq += [int(tok)]
+ args += [seq]
+ else:
+ raise ArgError('Unknown argument type.')
+ return args, {}
+
+
+class TestParser(unittest.TestCase):
+
+ def test_tokenizer(self):
+ p = Parser()
+ self.assertEqual(p.tokenize(''), [])
+ self.assertEqual(p.tokenize(' '), [])
+ self.assertEqual(p.tokenize('abc'), ['abc'])
+ self.assertEqual(p.tokenize('a b\nc "d"'), ['a', 'b', 'c', 'd'])
+ self.assertEqual(p.tokenize('a "b\nc d"'), ['a', 'b\nc d'])
+ self.assertEqual(p.tokenize('a"b"c'), ['abc'])
+ self.assertEqual(p.tokenize('a\\b'), ['a\\b'])
+ self.assertEqual(p.tokenize('"a\\b"'), ['ab'])
+ self.assertEqual(p.tokenize('a"b'), ['ab'])
+ self.assertEqual(p.tokenize('a"\\"b'), ['a"b'])
+
+ def test_unhandled(self):
+ p = Parser()
+ self.assertEqual(p.parse(''), None)
+ self.assertEqual(p.parse(' '), None)
+ self.assertEqual(p.parse('x'), None)
+
+ def test_argsparse(self):
+ from functools import partial
+ p = Parser()
+ assertErr = partial(self.assertRaises, ArgError, p.argsparse)
+ assertErr('', ['foo'])
+ assertErr('string', [])
+ assertErr('string string', ['foo'])
+ self.assertEqual(p.argsparse('string', ('foo',)),
+ (['foo'], {}))
+ self.assertEqual(p.argsparse('string string', ('foo', 'bar')),
+ (['foo', 'bar'], {}))
+ assertErr('int:nonneg', [''])
+ assertErr('int:nonneg', ['x'])
+ assertErr('int:nonneg', ['-1'])
+ assertErr('int:nonneg', ['0.1'])
+ self.assertEqual(p.argsparse('int:nonneg', ('0',)),
+ ([0], {}))
+ assertErr('yx_tuple:nonneg', ['x'])
+ assertErr('yx_tuple:nonneg', ['Y:0,X:1'])
+ assertErr('yx_tuple:nonneg', ['Y:1,X:0'])
+ assertErr('yx_tuple:nonneg', ['Y:1.1,X:1'])
+ assertErr('yx_tuple:nonneg', ['Y:1,X:1.1'])
+ self.assertEqual(p.argsparse('yx_tuple:nonneg', ('Y:1,X:2',)),
+ ([(1, 2)], {}))
+ assertErr('seq:int:nonneg', [''])
+ assertErr('seq:int:nonneg', [','])
+ assertErr('seq:int:nonneg', ['a'])
+ assertErr('seq:int:nonneg', ['a,1'])
+ assertErr('seq:int:nonneg', [',1'])
+ assertErr('seq:int:nonneg', ['1,'])
+ self.assertEqual(p.argsparse('seq:int:nonneg', ('1,2,3',)),
+ ([[1, 2, 3]], {}))