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
Carter Schonwald
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
gmail.com> wrote:
Unlike dot notation, this is unambiguous and doesn't conflict with any
existing syntax (AFAIK). ...
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