Curried class methods?

[Carl Banks]

Scott Lamb wrote:
> I'm trying to dynamically generate class methods which have access to
> some state passed in at creation time. (Basically as a workaround to
> twisted's trial not having a way to dynamically add stuff. Plain
> unittest seems to have TestSuite, but the trial runner doesn't know
> about it.)
>
> My first attempt might better illustrate this -
>
>     class Foo:
>         def generalized(self, ctx):
>             print 'my ctx is %r' % ctx
>
>     for i in ['a','b','c']:
>         setattr(Foo, i, lambda self: self.generalized(i))
>
>     foo = Foo()
>     foo.a()
>     foo.b()
>     foo.c()
>
> but this prints "my ctx is c" three times; I'd hoped for a, b, c, of
> course.

def build(j):
   setattr(Foo, j, lambda self: self.generalized(j))
for i in ["a","b","c"]:
   build(i)

Each call of the the build function creates its own cell "j" that the
lambda references.


Carl Banks