#!/usr/bin/env python
from functools import wraps
def returns(rettype):
def check(ret):
if not isinstance(ret, rettype): raise InputParameterError()
return ret
def returnchecker(func):
@wraps(func)
def _func(*args, **kwargs):
return check(func(*args, **kwargs))
_func.returns = rettype
return _func
return returnchecker
def takes(*argtypes, **kwtypes):
def check(args, kwargs):
if not len(args) == len(argtypes): raise InputParameterError()
if not all(isinstance(a, b) for a, b in zip(args, argtypes)): raise InputParameterError()
if not len(kwargs) == len(kwtypes): raise InputParameterError()
if not set(kwargs) == set(kwtypes) : raise InputParameterError()
if not all(isinstance(kwargs[kw], kwtypes[kw]) for kw in kwtypes): raise InputParameterError()
def typechecker(func):
@wraps(func)
def _func(*args, **kwargs):
check(args, kwargs)
return func(*args, **kwargs)
_func.signature = argtypes, kwtypes
return _func
return typechecker
## note: there is a more comprehensive signature checking recipe #426123
## http://code.activestate.com/recipes/426123-method-signature-checking-decorators/
## this recipe is compatible with that recipe, simply copy that recipe to
## "signature.py" and uncomment the following import lines ##
##
## from signature import *
class InputParameterError(Exception): pass
def overloaded(func):
@wraps(func)
def overloaded_func(*args, **kwargs):
for f in overloaded_func.overloads:
try:
return f(*args, **kwargs)
except (InputParameterError, TypeError):
pass
else:
raise TypeError("No compatible signatures")
def overload_with(func):
overloaded_func.overloads.append(func)
return overloaded_func
overloaded_func.overloads = [func]
overloaded_func.overload_with = overload_with
return overloaded_func
#############
if __name__ == '__main__':
@overloaded
def a():
print 'no args a'
pass
@a.overload_with
def a(n):
print 'arged a'
pass
a()
a(4)
@overloaded
@returns(int)
@takes(int, int, float)
def foo(a, b, c):
return int(a * b * c)
@foo.overload_with
@returns(int)
@takes(int, float, int, int)
def foo(a, b, c, d):
return int(a + b + c)
@foo.overload_with
@returns(int)
@takes(int, float, c=int)
def foo(a, b, c):
return int(a + b + c)
print foo(2, 3, 4.)
print foo(10, 3., c=30)
print foo(1, 9., 3, 3)
print foo('string')
Diff to Previous Revision
--- revision 1 2010-02-23 15:19:47
+++ revision 2 2010-04-11 11:16:48
@@ -2,11 +2,10 @@
from functools import wraps
-class InvalidSignature(Exception): pass
def returns(rettype):
def check(ret):
- if not isinstance(ret, rettype): raise InvalidSignature()
+ if not isinstance(ret, rettype): raise InputParameterError()
return ret
def returnchecker(func):
@wraps(func)
@@ -17,14 +16,14 @@
return _func
return returnchecker
-def signature(*argtypes, **kwtypes):
+def takes(*argtypes, **kwtypes):
def check(args, kwargs):
- if not len(args) == len(argtypes): raise InvalidSignature()
- if not all(isinstance(a, b) for a, b in zip(args, argtypes)): raise InvalidSignature()
+ if not len(args) == len(argtypes): raise InputParameterError()
+ if not all(isinstance(a, b) for a, b in zip(args, argtypes)): raise InputParameterError()
- if not len(kwargs) == len(kwtypes): raise InvalidSignature()
- if not set(kwargs) == set(kwtypes) : raise InvalidSignature()
- if not all(isinstance(kwargs[kw], kwtypes[kw]) for kw in kwtypes): raise InvalidSignature()
+ if not len(kwargs) == len(kwtypes): raise InputParameterError()
+ if not set(kwargs) == set(kwtypes) : raise InputParameterError()
+ if not all(isinstance(kwargs[kw], kwtypes[kw]) for kw in kwtypes): raise InputParameterError()
def typechecker(func):
@wraps(func)
@@ -36,13 +35,21 @@
return _func
return typechecker
+## note: there is a more comprehensive signature checking recipe #426123
+## http://code.activestate.com/recipes/426123-method-signature-checking-decorators/
+## this recipe is compatible with that recipe, simply copy that recipe to
+## "signature.py" and uncomment the following import lines ##
+##
+## from signature import *
+
+class InputParameterError(Exception): pass
def overloaded(func):
@wraps(func)
def overloaded_func(*args, **kwargs):
for f in overloaded_func.overloads:
try:
return f(*args, **kwargs)
- except (InvalidSignature, TypeError):
+ except (InputParameterError, TypeError):
pass
else:
raise TypeError("No compatible signatures")
@@ -56,31 +63,39 @@
#############
-@overloaded
-def a():
- print 'no args a'
- pass
-@a.overload_with
-def a(n):
- print 'arged a'
- pass
-a()
-a(4)
+if __name__ == '__main__':
+ @overloaded
+ def a():
+ print 'no args a'
+ pass
+ @a.overload_with
+ def a(n):
+ print 'arged a'
+ pass
+ a()
+ a(4)
-@overloaded
-@returns(int)
-@signature(int, int, float)
-def foo(a, b, c):
- return int(a * b * c)
+ @overloaded
+ @returns(int)
+ @takes(int, int, float)
+ def foo(a, b, c):
+ return int(a * b * c)
-@foo.overload_with
-@returns(int)
-@signature(int, float, c=int)
-def foo(a, b, c):
- return int(a + b + c)
+ @foo.overload_with
+ @returns(int)
+ @takes(int, float, int, int)
+ def foo(a, b, c, d):
+ return int(a + b + c)
-print foo(2, 3, 4.)
-print foo(10, 3., c=30)
-print foo(1, 9., 3, 3)
+ @foo.overload_with
+ @returns(int)
+ @takes(int, float, c=int)
+ def foo(a, b, c):
+ return int(a + b + c)
+
+ print foo(2, 3, 4.)
+ print foo(10, 3., c=30)
+ print foo(1, 9., 3, 3)
+ print foo('string')
