pyfpm stands for PYthon Functional Pattern Matching. It's been heavily
inspired by the Pattern Matching and Case Classes implementation in Scala.
Build status at Travis CI:
With pyfpm you can unpack objects using the Unpacker class:
unpacker = Unpacker()
unpacker('head :: tail') << (1, 2, 3)
unpacker.head # 1
unpacker.tail # (2, 3)or function parameters using the match_args decorator:
@match_args('[x:str, [y:int, z:int]]')
def match(x, y, z):
return (x, y, z)
match('abc', (1, 2)) # ('abc', 1, 2)You can also create simple matchers with lambda expressions using the Matcher
class:
what_is_it = Matcher([
('_:int', lambda: 'an int'),
('_:str', lambda: 'a string'),
('x', lambda x: 'something else: %s' % x),
])
what_is_it(10) # 'an int'
what_is_it('abc') # 'a string'
what_is_it({}) # 'something else: {}'or more complex ones using the Matcher.handler decorator:
parse_options = Matcher()
@parse_options.handler("['-h'|'--help', None]")
def help():
return 'help'
@parse_options.handler("['-o'|'--optim', level:int] if 1<=level<=5")
def set_optimization(level):
return 'optimization level set to %d' % level
@parse_options.handler("['-o'|'--optim', bad_level]")
def bad_optimization(bad_level):
return 'bad optimization level: %s' % bad_level
@parse_options.handler('x')
def unknown_options(x):
return 'unknown options: %s' % repr(x)
parse_options(('-h', None)) # 'help'
parse_options(('--help', None)) # 'help'
parse_options(('-o', 3)) # 'optimization level set to 3'
parse_options(('-o', 0)) # 'bad optimization level: 0'
parse_options(('-v', 'x')) # "unknown options: ('-v', 'x')"For more information, see the files in the examples directory alongside the
links within them, or read the docs.
pyfpm is in PyPi:
$ pip install pyfpm