Chance Ginger wrote:
> It isn't a syntax error...I tried it before I posted. In fact
> def t(x) :
> def I(x) : return x
> return I
>
> is correct.
tabs don't make it through all channels. don't use tabs for
indentation when you post to newsgroups or mailing lists.
and @(Y) is not valid Python syntax. no amount of indentation
will change that.
> Decorators are a way to add "syntactic" sugar to Python,
> extending it in ways that make it useful for tools.
that's a rather narrow view of what a decorator does, and doesn't
help much in understanding how they work.
which is unfortunate, because it's very simple: decorators are simply
ordinary callables, and the result of the decoration is whatever the
callable returns.
in fact, any callable can be used to decorate a function:
>>> @str
... def foo(bar):
... pass
...
>>> foo
'<function foo at 0x00986730>'
>>> foo("bar")
Traceback (most recent call last):
File "<stdin>", line 1, in ?
TypeError: 'str' object is not callable
and it's all done at runtime; there is no magic involved whatsoever.
>>> @open
... @str
... def bar(foo):
... pass
...
Traceback (most recent call last):
File "<stdin>", line 1, in ?
IOError: [Errno 2] No such file or directory: '<function bar at 0x009867F0>'
> I am trying to do is lessen the impact on the time used in
> executing Python code when I use some forms of decorators.
if you don't want Python to execute some code, all you have to do is
to make sure that it isn't called.
</F>
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