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| Date: | -- (:) |
| From: | Andreas Rossberg <rossberg@p...> |
| Subject: | Re: [Caml-list] Record pattern matching |
> > You'd rather be forced to code something like:
> >
> > function { a=a; b=_ } -> a;;
> >
> > where all the fields have to be named, but some of them can
> > be specified as ignored?
No, but as Don suggested having alternative syntax would be preferable.
SML for example distinguishes the patterns
{a = p}
and
{a = p, ...}
> I guess the point is that I don't use record pattern matching much, and
> where I do I don't want partial matches. Or at least I have a cases
> where enforcing full matching would catch more bugs.
This has been my experience as well when modifying record types.
> > There is a sense in which
> >
> > record.a
> >
> > is just a shorthand for
> >
> > match record with { a=value } -> value
> >
> > which means that you might argue that the notation
> >
> > record.a
> >
> > should be completed by naming every field too :-)
In SML the record selection function #a in fact is sugar for
fn {a=x, ...} => x
Best regards,
- Andreas
--
Andreas Rossberg, rossberg@ps.uni-sb.de
"Computer games don't affect kids.
If Pac Man affected us as kids, we would all be running around in
darkened rooms, munching pills, and listening to repetitive music."
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