Why not allow empty record updates?

[Simon Peyton-Jones]

Hmm yes. Fair enough.  Does anyone care enough?  I can see (now) that it wouldn't really be hard.

| -----Original Message-----
| From: glasgow-haskell-users-bounces at haskell.org [mailto:glasgow-haskell-users-
| bounces at haskell.org] On Behalf Of Yitzchak Gale
| Sent: 15 November 2011 11:16
| To: Malcolm Wallace
| Cc: GHC-users List
| Subject: Re: Why not allow empty record updates?
| 
| Simon Peyton-Jones wrote:
| >> Trouble is, what type does this have?
| >>       f x = x {}
| 
| Malcolm Wallace wrote:
| > Empty record patterns {} are permitted, even for types
| > that are not declared with named fields.
| > So I don't see why an empty record update should
| > require the type to be declared with named fields either.
| 
| Yes. The translation of record updates given in the Report
| makes perfect sense for {}. It is only forbidden by
| "n >= 1", but no reason is given for that restriction.
| 
| According to that translation, the type of x {} is
| the type of the case expression it translates to.
| 
| Thanks,
| Yitz
| 
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