def _mkGeneric(oldfunc,argname):
funcname = oldfunc.__name__
args, varargs, kwargs, defaults = inspect.getargspec(oldfunc)
if defaults:
tmpd = ["=__gfDefaults[%s]" % i for i in range(len(defaults))]
else:
tmpd = None
argspec = inspect.formatargspec(
args, varargs, kwargs, tmpd, formatvalue=lambda x:x)
outargs = inspect.formatargspec(args,varargs,kwargs)
protocol = protocols.Protocol()
d={}
s= """
def setup(__gfProtocol, __gfDefaults):
def %(funcname)s%(argspec)s:
__gfWhat = __gfProtocol(%(argname)s,None)
if __gfWhat is None:
raise NoApplicableMethods(%(argname)s)
else:
%(argname)s = __gfWhat[0]
return __gfWhat[1]%(outargs)s
return %(funcname)s
""" % locals()
exec(s, globals(),d); func = d['setup'](protocol,defaults)
def when(cond):
"""Add following function to this GF, using 'cond' as a guard"""
def callback(frm,name,value,old_locals):
declarePredicate(cond, protocol, lambda ob: (ob,value))
if old_locals.get(name) is func:
return func
return value
return decorate_assignment(callback)
def addMethod(cond,func):
"""Use 'func' when dispatch argument matches 'cond'"""
declarePredicate(cond, protocol, lambda ob: (ob,func))
def clone():
"""Return a simple generic function that "inherits" from this one"""
f = _mkGeneric(oldfunc,argname)
protocols.declareAdapter(
protocols.NO_ADAPTER_NEEDED,[f.protocol],forProtocols=[protocol]
)
return f
func.addMethod = addMethod
func.when = when
func.clone = clone
func.protocol = protocol
func.__doc__ = oldfunc.__doc__
protocols.adviseObject(func,provides=[IExtensibleFunction])
return func
def __init__(self, func):
self.delegate, args = _mkNormalizer(func, self)
self.delegate.__dict__ = dict([(k, getattr(self, k))
for k in dir(self.__class__)
if not k.startswith('_')])
self.delegate.__doc__ = self.__doc__ = func.__doc__
protocols.adviseObject(self.delegate, [IGenericFunction])
self.__name__ = func.__name__
self.__call__ = self.delegate
Dispatcher.__init__(self, args)
def __init__(self,func):
self.delegate, args = _mkNormalizer(func, self)
self.delegate.__dict__ = dict(
[(k,getattr(self,k))
for k in dir(self.__class__) if not k.startswith('_')]
)
self.delegate.__doc__ = self.__doc__ = func.__doc__
protocols.adviseObject(self.delegate,[IGenericFunction])
self.__name__ = func.__name__; self.__call__ = self.delegate
Dispatcher.__init__(self,args)
def _mkGeneric(oldfunc, argname):
funcname = oldfunc.__name__
args, varargs, kwargs, defaults = inspect.getargspec(oldfunc)
if defaults:
tmpd = ["=__gfDefaults[%s]" % i for i in range(len(defaults))]
else:
tmpd = None
argspec = inspect.formatargspec(args,
varargs,
kwargs,
tmpd,
formatvalue=lambda x: x)
outargs = inspect.formatargspec(args, varargs, kwargs)
protocol = protocols.Protocol()
d = {}
s = """
def setup(__gfProtocol, __gfDefaults):
def %(funcname)s%(argspec)s:
__gfWhat = __gfProtocol(%(argname)s,None)
if __gfWhat is None:
raise NoApplicableMethods(%(argname)s)
else:
%(argname)s = __gfWhat[0]
return __gfWhat[1]%(outargs)s
return %(funcname)s
""" % locals()
exec(s, globals(), d)
func = d['setup'](protocol, defaults)
def when(cond):
"""Add following function to this GF, using 'cond' as a guard"""
def callback(frm, name, value, old_locals):
declarePredicate(cond, protocol, lambda ob: (ob, value))
if old_locals.get(name) is func:
return func
return value
return decorate_assignment(callback)
def addMethod(cond, func):
"""Use 'func' when dispatch argument matches 'cond'"""
declarePredicate(cond, protocol, lambda ob: (ob, func))
def clone():
"""Return a simple generic function that "inherits" from this one"""
f = _mkGeneric(oldfunc, argname)
protocols.declareAdapter(protocols.NO_ADAPTER_NEEDED, [f.protocol],
forProtocols=[protocol])
return f
func.addMethod = addMethod
func.when = when
func.clone = clone
func.protocol = protocol
func.__doc__ = oldfunc.__doc__
protocols.adviseObject(func, provides=[IExtensibleFunction])
return func
is, you can do this::
myInitCtx = binding.Make(naming.InitialContext)
in a class to create a 'myInitCtx' attribute. This can be useful if
you will be using naming functions a lot and would like to hang onto
an initial context.
"""
return spi.getInitialContext(parent, componentName, **options)
from peak.binding.interfaces import IComponentFactory
from protocols import adviseObject
adviseObject(InitialContext, provides=[IComponentFactory])
del IComponentFactory, adviseObject
from peak.api import NOT_GIVEN
def lookup(parent, name, default=NOT_GIVEN, **options):
"""Look up 'name' in the default initial context for 'parent', w/'options'
This is just a shortcut for calling::
naming.InitialContext(parent,**options)[name]
"""
return InitialContext(parent, **options).lookup(name, default)
