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Created Dec 13, 2009
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class Operation:
def __eq__(self, other):
return self.__class__ == other.__class__
def matches(self, line):
def zip_strs(a, b):
def separate(str):
return [char for char in str]
return zip(separate(a), separate(b))
self.match_args = []
for syntax_part, line_part in zip_strs(self.syntax, line):
if syntax_part == '%':
arg = line_part
elif syntax_part != line_part:
return False
return True
def match(self):
return self.__class__(*self.match_args)
class Pen(Operation):
syntax = 'P %'
def __init__(self, number=0):
self.number = int(number)
def __eq__(self, other):
return self.number == other.number
class Down(Operation): syntax = 'D'
class Up(Operation): syntax = 'U'
class Direction(Operation):
def __init__(self, amount=0):
self.amount = int(amount)
def __eq__(self, other):
return self.amount == other.amount
class East(Direction): syntax = 'E %'
class North(Direction): syntax = 'N %'
class South(Direction): syntax = 'S %'
class West(Direction): syntax = 'W %'
class Parser:
def __init__(self, operations):
self.operations = operations
def parse(self, line):
ret = []
for line in code.splitlines():
return ret
def parse_line(self, line):
for operation in self.operations:
if operation.matches(line):
return operation.match()
code = '''P 2 # select pen 2
D # pen down
W 2 # draw west 2cm
N 1 # then north 1
E 2 # then east 2
S 1 # then back south
U # pen up'''
operations = (Pen(), Down(), West(), North(), East(), South(), Up(), )
parser = Parser(operations)
result = parser.parse(code)
assert result[0] == Pen(2)
assert result[1] == Down()
assert result[2] == West(2)
assert result[3] == North(1)
assert result[4] == East(2)
assert result[5] == South(1)
assert result[6] == Up()
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