On Sun, Jul 18, 2010 at 5:19 PM, Eitan Goldshtrom
<thesource...@gmail.com> wrote:
> Silly question, but I can't find the answer on the net. I think I'm just
> using the wrong words in my search. I'm looking for a way to create constant
> expressions in Haskell. The C/C++ equivalent of what I'm talking about is
>
> #define NAME VALUE
>
> I want an expression, or really just numbers for what I'm doing, that the
> compiler will put into the program at the designated places, instead of
> storing it in memory like a variable.
Unless you want to pattern match the value, just say
myconst :: Double -- or anything else
myconst = 7.14
{-# INLINE myconst #-}
Voilà!
This doesn't work for pattern matching, however, if you say
f myconst = ...
then 'myconst' will be the name of that argument that could be
anything, and not just 7.14.
You could, however, use CPP as well
{-# LANGUAGE CPP #-}
#define MYCONST 7.14
f MYCONST = ...
but I'm against using CPP unless you need it.
Cheers,
--
Felipe.
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