If you really want to hunt for unused syntax and we wind up needing a (.) analogue then (->) is currently a reserved operator, so opening it up for use at the term level could be made to work, and there is a precedent with c/c++ pointer dereferencing.
-Edward On Mon, Jul 1, 2013 at 1:10 AM, Edward Kmett <ekm...@gmail.com> wrote: > (#) is a legal operator today and is used in a number of libraries. > > > On Sun, Jun 30, 2013 at 11:38 PM, <amin...@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_clay...@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@haskell.org >> > http://www.haskell.org/mailman/listinfo/glasgow-haskell-users >> >> _______________________________________________ >> Glasgow-haskell-users mailing list >> Glasgow-haskell-users@haskell.org >> http://www.haskell.org/mailman/listinfo/glasgow-haskell-users >> > >
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