On 10/18/05, Guido van Rossum <[EMAIL PROTECTED]> wrote:
> I wonder if at some point in the future Python will have to develop a
> macro syntax so that you can write
>
> Property foo:
> def get(self): return self._foo
> ...etc...
This reminds me of an idea I have kept in my drawer for a couple of years or so.
Here is my proposition: we could have the statement syntax
<callable> <name> <tuple>:
<definitions>
to be syntactic sugar for
<name> = <callable>(<name>, <tuple>, <dict-of-definitions>)
For instance properties could be defined as follows:
def Property(name, args, dic):
return property(
dic.get('fget'), dic.get('fset'), dic.get('fdel'), dic.get('__doc__'))
Property p():
"I am a property"
def fget(self):
pass
def fset(self):
pass
def fdel(self):
pass
Another typical use case could be a dispatcher:
class Dispatcher(object):
def __init__(self, name, args, dic):
self.dic = dic
def __call__(self, action, *args, **kw):
return self.dic.get(action)(*args, **kw)
Dispatcher dispatch(action):
def do_this():
pass
def do_that():
pass
def default():
pass
dispatch('do_this')
Notice that the proposal is already implementable by abusing the class
statement:
class <name> <tuple>:
__metaclass__ = <callable>
<definitions>
But abusing metaclasses for this task is ugly. BTW, if the proposal was
implemented, the 'class' would become redundant and could be replaced
by 'type':
class <classname> <bases>:
<definitions>
<=>
type <classname> <bases>:
<definitions>
;)
Michele Simionato
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