[GHC] #9119: Additional symbols for XUnicodeSyntax

[GHC]

#9119: Additional symbols for XUnicodeSyntax
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        Reporter:  spacekitteh       |            Owner:
            Type:  feature request   |           Status:  patch
        Priority:  normal            |        Milestone:
       Component:  Compiler          |          Version:  7.8.2
  (Parser)                           |         Keywords:  unicode
      Resolution:                    |     Architecture:  Unknown/Multiple
Operating System:  Unknown/Multiple  |       Difficulty:  Easy (less than 1
 Type of failure:  None/Unknown      |  hour)
       Test Case:                    |       Blocked By:
        Blocking:                    |  Related Tickets:
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Comment (by spacekitteh):

 No, the parser didn't like it, @nomeata, that's why I changed it to
 {{{
 ,("⊦",   ITin, unicodeSyntaxEnabled)
 ,("∃",   ITlet, unicodeSyntaxEnabled)
 }}}

 As for the extra equality symbols, I only ended up implementing three
 which make more sense as synonyms for assignment rather than equality
 testing:

 {{{
  -- "Is estimated by"
 ,("≙",   ITequal, unicodeSyntaxEnabled)
 -- "Is definitally equal to"
 ,("≝",   ITequal, unicodeSyntaxEnabled)
 -- "Is measured by"
 ,("≞",   ITequal, unicodeSyntaxEnabled)
 }}}

 The first one would be useful for situations such as numerical
 integration: {{{ area ≙ rk4 f' }}}
 The second one would be useful with combinators: {{{ sum ≝ foldr1 (+) }}}
 The third one is useful for hardware IO:
 {{{
 accel ::() -> IO Double
 accel ≞ readAccelerometer()

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9119#comment:7>
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