On 12/22/11 2:28 PM, J. Garrett Morris wrote:
2011/12/22 Edward Kmett<ekm...@gmail.com>:
The change, however, was a deliberate _break_ with the standard that
passed through the library review process a few months ago, and is now
making its way out into the wild.
Is it reasonable to enquire how many standard-compliant implementations
of Haskell there are?
I believe the answer is (or on release of 7.4 will become) zero, unless
UHC is fully compliant. I seem to recall that GHC already had other
infelicities wrt the report, unless those had been fixed when I wasn't
looking.
However, this is (to some extent) inevitable, because the haskell'
process desires that things be already implemented before they are
considered for inclusion in the new standard. IIRC, the desire to
explicitly break from h2010 in this regard is as a preamble to getting
the change into h2012 or h2013. Unfortunately, due to how typeclasses
are defined there's no way to simultaneously implement the current
standard and the desired new standard in such a way that the two will be
able to interact (instead of duplicating all intersecting code so as to
compile separately against both standards).
While the requirement to state Eq and Show is a burden wrt the old
standard, it is fully compatible with it.
--
Live well,
~wren
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