[Python-Dev] Decorators with arguments are curries! (original) (raw)

Andrew Durdin adurdin at gmail.com
Sat Aug 7 15:13:50 CEST 2004

On Sat, 07 Aug 2004 15:00:13 +0200, "Martin v. Löwis" <martin at v.loewis.de> wrote:

Andrew Durdin wrote: > > Here the first decorator statement is bare, while the second one > includes parentheses and an argument; the first one looks like a > function reference, while the second looks like a function call.

Correct. And that is indeed the intended meaning. Did you try this out? It gives Traceback (most recent call last): File "b.py", line 9, in ? @foodecorator TypeError: bardecorator() takes exactly 2 arguments (1 given) (although, as you can see, the line number is off by one) See http://www.python.org/dev/doc/devel/ref/function.html on why this is so.

Ah! Quite so. The relevant quote would be: "The result [of the decorator expression] must be a callable, which is invoked with the function object as the only argument". I guess I didn't pay quite enough attention to the examples in PEP 318 to understand them properly :)

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