#1894: Add a total order on type constructors
-------------------------------------+--------------------------------------
Reporter: guest | Owner:
Type: feature request | Status: new
Priority: normal | Milestone:
Component: Compiler (Type checker) | Version: 6.8.1
Severity: normal | Keywords:
Testcase: | Architecture: Multiple
Os: Multiple |
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Several proposals for ExtensibleRecords can be implemented as libraries if
type constructors can be ordered globally.
This proposal is to add built-in types:
{{{
data LabelLT
data LabelEQ
data LabelGT
type family LabelCMP
}}}
such that, for any two datatypes
{{{
data N = N
data M = M
}}}
the instance {{{LabelCMP N M}}} takes one of the values {{{LabelLT,
LabelEQ, LabelGT}}} depending on the lexicographic ordering on the fully-
qualified names of {{{N}}} and {{{M}}}.
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/1894>
GHC <http://www.haskell.org/ghc/>
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