Michael Hudson wrote on 03/02/2006 09:36:30:
>
> Hmm.
>
> >>> funcTakingCallback(lamda x:x.method(zip, zop))
> >>> funcTakingCallback(methodcaller("method", zip, zop))
>
> I'm not sure which of these is clearer really. Are lambdas so bad?
> (FWIW, I haven't internalized itemgetter/attrgetter yet and still tend
> to use lambdas instead those too).
>
> A class I wrote (and lost) ages ago was a "placeholder" class, so if
> 'X' was an instance of this class, "X + 1" was roughly equivalent to
> "lambda x:x+1" and "X.method(zip, zop)" was roughly equivalent to your
> "methodcaller("method", zip, zop)". I threw it away when listcomps
> got implemented. Not sure why I mention it now, something about your
> post made me think of it...
>
The C++ library Boost makes use of this method, but has a number of
"placeholder" variables _1, _2, _3 ... _9 which can be combined to form
expressions. e.g _1 + _2 is the same as lambda x,y: x+y so maybe there
could be a lambda module that exposes placeholders like this. Pythons ones
will be better that the C++ ones because we would be able to delay
function calls as above with a much nicer syntax than the C++ versions.
E.g
_1.method(_2+_3) !
Cheers,
Ben
> Cheers,
> mwh
>
>
> --
> If you give someone Fortran, he has Fortran.
> If you give someone Lisp, he has any language he pleases.
> -- Guy L. Steele Jr, quoted by David Rush in comp.lang.scheme.scsh
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