Re: case-expression in function position causes error

[Jim White <jim at pagesmiths dot com>]

Per Bothner wrote:
> Sven Hartrumpf wrote:
>
> > A case-expression in a function position causes errors like this:
> >
> > > kawa ; current CVS version
> >
> > #|kawa:1|# (load "kawabug3.scm")
> > kawabug3.scm:2:4: warning - cannot convert literal (of type 
> > gnu.mapping.Values) to gnu.mapping.Procedure
> > #|kawa:2|# 
>
> The warning is correct, if confusing, because
> you have no else clause.
>
> I changed the error message in this case to the following.
> Would that make it easier to understand the message?
>
> kawabig3.scm:2:10: warning - cannot convert void to gnu.mapping.Procedure

For those still wondering what this means:

1) Since a case without an else-clause has an undefined value, Kawa 
compiles it as void.

2) Kawa sees the void as incompatible with Procedure because the case's 
value is the procedure in the expression, and so gives a warning.

3) As long as the case does match and so doesn't return void, the code 
works as expected.

4) If you want to get rid of the warning, supply an else-clause whose 
value is a Procedure, just like the other clauses.

Jim