Front page | perl.perl6.language |
Postings from May 2005
Larry Wall wrote:
>We have a bit of a problem with negative operators applied to junctions,
>as illustrated recently on PerlMonks. To wit, when a native English
>speaker writes
>
> if $a != 1 | 2 | 3 {...}
>
>they really mean one of:
>
> if not $a == 1 | 2 | 3 {...}
> if $a == none(1, 2, 3) {...}
>
>or, expressed in current understanding of negated ops:
>
> if $a != 1 & 2 & 3 {...}
> if $a != all(1, 2, 3) {...}
>
>They specifically do *not* mean
>
> if $a != any(1,2,3) {...}
>
>since that would always be true.
>
>
unless $a = none(1,2)
>I don't think we can allow this situation to stand. Either we have
>to make != and !~ and ne transform themselves via "not raising", or
>we have to disallow negative comparisons on junctions entirely.
>
>Opinions?
>
>
I go with option 2b: leave the syntax the way it is, but fire off a
warning, not an error when someone does this.
-- Rod Adams
Thread Previous
|
Thread Next