python - where is the instancemethod decorator? -

in code have method returns instance of class, this:

class myclass:   def fun( self, *args ): # method     return props( self, *args )  class props: # returned object   def __init__( self, parent, *args ):     self.parent = parent     self.args = args 

to keep things organized considering place props inside myclass. bypass fun , directly make class instance method of myclass, this:

class myclass:   @instancemethod # not exist!   class fun:     def __init__( self, parent, *args ):       self.parent = parent       self.args = args 

note comment - instancemethod decorator not exist.

is there way this, i.e. turn callable object instance method? if change @instancemethod @classmethod construction works, except of course parent class, not instance. surprised cannot find seems opposite operation.

curious have cleared up!

edit:

it seems question not clear. have member function, fun, returns not single value or tuple object full of data. data generated based on contents of myclass object , function arguments. initial code want. second code how prefer write it.

moreover noticed decorator looking following:

def instancemethod( cls ):   def f( *args ):     return cls( *args )   return f 

it is, of course, identical 'fun' method aimed bypass. note trivial 'return cls' not identical, though might seem @ first sight.

with decorator, second class definition valid , produces desired result, namely, a.fun() returns object (potentially) initialized based on data in a:

a = myclass() p = a.fun(1,2,3)  print        # <__main__.myclass instance @ 0xb775b84c> print p.parent # <__main__.myclass instance @ 0xb775b84c> print p.args   # (1, 2, 3) 

this still leaves me question if instancemethod defined here not available python builtin, because seems omission next classmethod , staticmethod. but, if not, suppose can live construction.

i'm not sure you're trying do, suspect want read on descriptors.

basically, descriptor attribute of class class defines __get__ , __set__ methods. in case, move code props.__init__ props.__set__, set props fun attribute of class, , should work want.