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PythonCurry

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July 26, 2008, at 12:12 PM by hodge - Fixed fatal flaw.
Added lines 6-7:
'''Update''': The initial version (see [[{$PageUrl}?action=diff|history]]) had a fatal flaw -- the argument list was shared between all versions of the curried function. The new version fixes this (and adds better testing :).

Changed lines 9-10 from:
# An attempt at implementing currying in Python.
to:
# An"""An attempt at implementing currying in Python.Python."""

Changed lines 14-24 from:
def __init__(self, f):
args, varargs, varkw, defaults = inspect.getargspec(f)

self._f = f
self._n = len(args)
self._arg_values = []

def __call__(self, *args):
self._arg_values.extend(args)
if len(self._arg_values) >= self._n:
return self._f(*self._arg_values)
to:
def __init__(self, ffunc, arg_names=None, arg_values=None):
args, varargs, varkw, defaults
self.func = inspect.getargspec(f)func

self._fif arg_names is None:
args, varargs, varkw, defaults = f
self._n = leninspect.getargspec(argsself.func)
self._arg_values
self.arg_names = []

def __call__(self, *args):
self._arg_values.extend(args)
if len(self._arg_values) >= self._n:
return self._f(*self._arg_values)args
Changed lines 21-32 from:
return self

def f(x,y):
return x + y
cf = Curry(f)
print cf(5)(6)

def g(x,y,z,w):
return (x - y) + (z - w)
cg = Curry(g)
print cg(6)(5)(4)(3)
to:
return selfself.arg_names = arg_names

def f(x,y):
return x + y
cf if arg_values is None:
self.arg_values = Curry(f)
print cf(5)(6)()
else:
self.arg_values = arg_values

def g def __call__(x,y,z,wself, *params):
return (x - y)
new_params = self.arg_values + (z - wparams
if len(new_params)
cg = Curry >= len(gself.arg_names):
return self.func(*new_params)
print cg
else:
return Curry(6)(5)(4)(3self.func, arg_names=self.arg_names,
arg_values=new_params)

if __name__ == "__main__":
print "Running some basic tests ..."

def f(x,y):
return x + y
cf = Curry(f)

cf_5 = cf(5)
cf_10 = cf(10)

assert cf(5)(6) == 11
assert cf_5(7) == 12
assert cf_10(12) == 22

def g(x,y,z,w):
return (x - y) + (z - w)
cg = Curry(g)

cg_2_1 = cg(2)(1)
cg_3_4_5 = cg(3)(4)(5)
cg_12 = cg(12)

assert cg(4)(3)(2)(1) == 2
assert cg_2_1(7)(5) == 3
assert cg_3_4_5(12) == -8
assert cg_12(2)(8)(4) == 14
Restore
July 24, 2008, at 03:30 PM by hodge - Curry?
Added lines 1-36:
!!Python Curry
[-24 July 2008-]

See the wikipedia article on [[wikipedia:Currying|Currying]] for an explanation of the basic concept.

=python [=
# An attempt at implementing currying in Python.

import inspect

class Curry(object):
def __init__(self, f):
args, varargs, varkw, defaults = inspect.getargspec(f)

self._f = f
self._n = len(args)
self._arg_values = []

def __call__(self, *args):
self._arg_values.extend(args)
if len(self._arg_values) >= self._n:
return self._f(*self._arg_values)
else:
return self

def f(x,y):
return x + y
cf = Curry(f)
print cf(5)(6)

def g(x,y,z,w):
return (x - y) + (z - w)
cg = Curry(g)
print cg(6)(5)(4)(3)

=]
Restore
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Page last modified on July 26, 2008, at 12:12 PM