Re: A possible alternative to dot notation for record access

* Carter Schonwald [2013-06-30 03:26:22-0400]

Otoh, would there be any ambiguity wrt applying functions to blocks?

eg f = (+ 1) h= f {let x = 7 in 3*x}, would that trip up the syntax?

This is not valid Haskell anyway (there's no such thing as "applying functions to blocks"). You can write h = f (let {x = 7} in 3*x) or h = f $ let {x = 7} in 3*x Roman

On Sun, Jun 30, 2013 at 2:59 AM, Judah Jacobson wrote:

...

Hi all,

I had a quick idea about record field syntax as specified in the GSoC project plan: http://hackage.haskell.org/trac/ghc/wiki/Records/OverloadedRecordFields/Plan .

Instead of "f.x" (to access field x of record f), maybe we could write "f{x}" as the record selection. That is, we'd reuse the brace notation which is already in place for record updates. Unlike dot notation, this is unambiguous and doesn't conflict with any existing syntax (AFAIK). It would also generalize to "f{x}{y}{z}" instead of "f.x.y.z".

This proposal would add two new forms of expressions:

f{x} to access field x of data f ({x}) = \f -> f{x} as a field access section

Additionally, it seems like record mutation expressions could also have sections:

({x=2}) = \f -> f{x=2}

That actually seems useful by itself, regardless of whether we use dot notation for field access.

Best, -Judah

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