[Haskell-cafe] Names in a record changes read behavior?
Brandon Allbery
allbery.b at gmail.com
Mon Jul 27 20:56:29 UTC 2015
On Mon, Jul 27, 2015 at 4:25 PM, Mike Meyer <mwm at mired.org> wrote:
> OK, why won't read accept the same syntax as the REPL? I can see wanting
> Read and Show to be inverses of each other, though I think it's a bit
> misguided. But if we're going to be that strict about them being inverses,
> shouldn't we also insist that the READ eval print loop only accept what
> read will accept?
Partly because ReadS isn't a very good parser, partly because of compliance
with
https://www.haskell.org/onlinereport/haskell2010/haskellch11.html#x18-18600011.4;
notably:
- If the constructor is defined using record syntax, the derived Read will
parse only the record-syntax form, and furthermore, the fields must be
given in the same order as the original declaration.
--
brandon s allbery kf8nh sine nomine associates
allbery.b at gmail.com ballbery at sinenomine.net
unix, openafs, kerberos, infrastructure, xmonad http://sinenomine.net
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