[Python-ideas] anonymous object support
Carl Matthew Johnson
cmjohnson.mailinglist at gmail.com
Sun Aug 7 01:41:27 CEST 2011
On Aug 6, 2011, at 12:53 PM, Devin Jeanpierre wrote:
> My favorite declarative-namedtuple hack is http://code.activestate.com/recipes/500261-named-tuples/#c16
>
> Devin
For non-link followers:
def _namedtuple(func):
return namedtuple(func.__name__, func.__code__.co_varnames)
@_namedtuple
def Point(x,y):
pass
That is very clever, but it kind of illustrates my point about needing a new keyword. When you see "def" don't you naturally think, "OK, what comes out of this will be a function named Point." But what comes out of this is not a function. It's a namedtuple, which is quite different…
A similar case can be made about
@sort_list_with_keyfunc(my_list)
def result(item):
...
return normalized_item
It's a neat way of getting out of writing the keyfunc before the sort, but it's a bad practice because you're def-ing a sorted list, not a function.
Also a Ruby-like each can be done through abuse of decorators
@each(my_list)
def squared_list(item):
return item ** 2
Neat but it breaks the reader's expectations. (Also, a list comprehension is shorter.)
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