[Haskell] Re: [Haskell-cafe] field record update syntax

Jacques Carette carette at mcmaster.ca
Fri Jan 28 09:34:28 EST 2005

"S. Alexander Jacobson" <alex at alexjacobson.com> wrote:
> (Moved to Haskell list because this is now a suggestion for the language)
> I do a lot of this soft of thing.
>    foo {bar = fn $ bar foo
>        ,baz = fn2 $ baz foo
>        }
> It would be much nicer if this syntax did the equivalent:
>    foo {bar \= fn
>        ,baz \= fn2
>        }
> -Alex-

What about 'lifting' this higher?  You are (essentially) suggesting a nice syntax for constructing functions from a 
record to itself.  While your syntax is essentially pointfree, the semantics is 'pointwise' (in that it refers to a 
specific record) -- not to be confused with the fact that any such function needs to be done compontent-wise.

Wouldn't be even more convenient (as well as more 'functional') if a syntax like
    \foo {bar \= fn
         ,baz \= fn2
built a record-to-record function?  [The \foo might even be enough to allow bar = fn instead of bar = fn].


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