[Haskell-cafe] How to "Show" an Operation?
Martin.Drautzburg at web.de
Thu Jun 10 13:44:27 EDT 2010
On Thursday, 10. June 2010 00:08:34 Luke Palmer wrote:
> Or just:
> apply = val_of
> So, to summarize: if you have something that isn't a function and you
> want to use it like a function, convert it to a function (using
> another function :-P). That's all. No syntax magic, just say what
> you're doing.
The reason I was asking is the following: suppose I have some code which uses
some functions, and what it primarily does with those functions is CALL them
in different orders.
Now at a later point in time I decide I need to give names to those functions
because at the end I need to print information about the functions which
together solved a certain problem. Think of my problem as "In which order do
I have to call f,g,h such that (f.g.h) 42 = 42?".
I don't want to change all places where those functions are called
into "apply" style. Therefore I was looking for some idiom like the python
__call__() method, which, when present, can turn just about anything into a
I could change the *definition* of my original functions into "apply" style
and the rest of the code would not notice any difference. But that does not
really help, because in the end I want to Show something like [g,h,f], but my
functions would no longer carry names.
Alternatively I could associate functions with names in some association
function, but that function simply has to "know to much" for my taste.
The thing is, I only need the names at the very end. Throughout the majority
of the computation they should stay out of the way.
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