Hello,
I think the "it may be confusing to novices" argument tends to be
over-used and we should be careful before we make language decisions
solely based on it. At the very least, when there is a suggestion
that something might be confusing to someone, there should be an
explanation of what/why/to whom it is confusing.
I think record puns are a nice feature, it is easy to explain, and
without them the Haskell record system is less useful, at least to me.
By the way, if I recall correctly, in Johan Nordlander's O'Hugs the ..
notation (called record packing, I think) could also be used to create
record values. I think it worked like this:
data Point = Point { x,y :: Int }
pt = let { x = 3; y = 4 } in Point { .. }
The ".." is expanded to "{x = x, y = y}" based on the fields for the
particular constructor. It seems that if we have the "Point { .. }"
pattern, we should also have the constructor version. What do people
think?
-Iavor
On 10/31/06, Seth Kurtzberg <[EMAIL PROTECTED]> wrote:
On Tue, 31 Oct 2006 13:59:45 +0300
Bulat Ziganshin <[EMAIL PROTECTED]> wrote:
> Hello Neil,
>
> Tuesday, October 31, 2006, 4:04:23 AM, you wrote:
>
> >> > puns like Foo { .. } would be great too.
> >>
> >> I'd vote for enabling them with a command line switch, rather than by
default, as they can be confusing to folks learning the language.
>
> > How discussions come full circle :) I started this discussion on the
> > Hugs users list because I want to _remove_ the command line switch for
> > puns from Yhc. I'm not overly fussed whether I remove the entire
> > feature, or just remove the command line and make it always on by
> > default, but I do want the command line switch gone!
>
> compiler switch can't be made a part of Haskell' :)
>
> and anyway, i don't see how cmdline switch may help noivices - when
> they use ".." by mistake and program mysteriously not fails? or when
> they stare at the other's program and understand that this unknown
> ".." work only because this program compiled with some special switch?
I wasn't talking about the .., I was talking about the primary issue raised by
the email, which has nothing to do with ..
Instead of assuming that I was saying something totally useless and worthless,
it might not be a bad idea to respond to _my_ email, not an email which
contains a quote of one line from my email.
>
> and yes, record puns seems very ggod candidate for H'. it's widely
> used (i used it until switched to GHC), it was already in Haskell, and
> now it is impelemnted by every compiler
>
> wildcard puns is more discussible, but i personally need this feature
>
>
> --
> Best regards,
> Bulat mailto:[EMAIL PROTECTED]
>
>
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