A possible alternative to dot notation for record access

[Edward Kmett]

(#) is a legal operator today and is used in a number of libraries.

On Sun, Jun 30, 2013 at 11:38 PM, <amindfv at gmail.com> wrote:

> As long as we're bikeshedding...
>
> Possibly '#' is unused syntax -- Erlang uses it for its records too, so we
> wouldn't be pulling it out of thin air. E.g. "person#firstName"
>
> Tom
>
>
> El Jun 30, 2013, a las 22:59, AntC <anthony_clayden at clear.net.nz>
> escribió:
>
> >> Carter Schonwald <carter.schonwald <at> gmail.com> writes:
> >>
> >> indeed, this relates / augments record puns syntax already in
> > GHC http://www.haskell.org/ghc/docs/latest/html/users_guide/syntax-
> > extns.html#record-puns.
> >
> > Uh-oh. That documentation gives an example, and it exactly explains the
> > weird type-level error I got when I tried to use the proposed syntax
> > myself:
> >
> >    Note that:
> >
> >    *   Record punning can also be used in an expression, writing, for
> > example,
> >
> >        let a = 1 in C {a}            -- !!!
> >
> >        instead of
> >
> >        let a = 1 in C {a = a}
> >
> >        The expansion is purely syntactic, so the expanded right-hand side
> > expression refers to the nearest enclosing variable that is spelled the
> > same as the field name.
> >
> > IOW the proposal _does_ conflict with existing syntax. (And I guess I can
> > see a use for the example. Note that outside of that let binding, `a`
> > would be a field selector function generated from the data decl in which
> > field `a` appears -- that's the weirdity I got.)
> >
> > I suppose the existing syntax has a data constructor in front of the
> > braces, whereas the proposal wants a term. But of course a data
> > constructor is a term.
> >
> > So the proposal would be a breaking change. Rats! Is anybody using that
> > feature?
> >
> >>
> >> On Sun, Jun 30, 2013 at 2:59 AM, Judah Jacobson <judah.jacobson <at>
> > gmail.com> wrote:
> >>
> >> Unlike dot notation, this is unambiguous and doesn't conflict with any
> > existing syntax (AFAIK). ...
> >
> >
> > _______________________________________________
> > Glasgow-haskell-users mailing list
> > Glasgow-haskell-users at haskell.org
> > http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
>
> _______________________________________________
> Glasgow-haskell-users mailing list
> Glasgow-haskell-users at haskell.org
> http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.haskell.org/pipermail/glasgow-haskell-users/attachments/20130701/fa1fbda0/attachment.htm>