What I meant:
is this reasonable for future Haskell to make
a variable _foo equivalent to `_'
?
In this case, one can use _foo as a self-commenting dummy
variable:
let (x, _newEqs, _newVars) = f a
(y, _newEqs, newVars ) = f b
in
x:y:newVars
These _foo help to recall the type of f (suppose f is in
another file, so that one needs to search and recall).
This makes it easier to read/understand the program.
-----------------
Serge Mechveliani
[EMAIL PROTECTED]
On Wed, Dec 29, 2004 at 06:17:30PM +0000, Keean Schupke wrote:
> Except for GHC, where a variable staring with an '_' will not report a
> warning
> if it is unused in the body of a funtion:
>
> let _ = x in y -- no warning
> let result = x in y -- waring about result being unused
> let _result = x in y -- no warning, but variable can still be used.
>
> Keean.
>
> Duncan Coutts wrote:
>
> >In message <[EMAIL PROTECTED]> "Serge D. Mechveliani"
> ><[EMAIL PROTECTED]> writes:
> >
> >
> >>Dear Haskellers, dear GHC team,
> >>
> >>Is a variable `_x' equivalent to `_'
> >>
> >>
> >
> >No, '_x' is a perfectly ordinary variable. The only special "dummy variable"
> >(a
> >pattern that matches anything but does not bind a varialbe) is '_'.
> >
> >
> >
> >>Does really Haskell mean this? It this reasonable?
> >>How to set self-commenting dummy variables?
> >>
> >>
> >
> >You can use them as dummy variables by never using them in an expression
> >context, only in pattern/binding context. As you noted they should be unique
> >withing each scope.
> >
> >Duncan
> >_______________________________________________
> >Glasgow-haskell-users mailing list
> >[email protected]
> >http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
> >
> >
>
>
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