[Haskell-cafe] YAWQ (Yet Another Wash Question)
jules at jellybean.co.uk
Thu Feb 24 12:22:40 EST 2005
On 24 Feb 2005, at 16:42, John Goerzen wrote:
> Thanks for everyone that's helped me out with my Wash questions. I
> one more.
> I have a textInputField that I only want to display on a form in
> cituations. I can't figure out how to make this work. For instance:
> ... do if cond
> then x <- textInputField ...
> else ()
> submit ...
> Well, two problems there... first, the scope of the x doesn't reach to
> the submit. Second, there's a type issue. So I thought maybe I could
> figure out something like this:
Well, how could this possibly work (that is, how could 'x' be visible
at the point of submission)? If you go down the 'else' branch, what
value should x have?
The scoping rule is like that for a very good reason...
Once you know what value x is supposed to have down the else branch
then you will be able to do something like:
x <- if cond then textInputField ... else return ...
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