[GHC] #4359: Implement lambda-case/lambda-if

[GHC]

#4359: Implement lambda-case/lambda-if
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  Reporter:  batterseapower    |          Owner:                  
      Type:  feature request   |         Status:  new             
  Priority:  normal            |      Milestone:  7.6.1           
 Component:  Compiler          |        Version:  7.1             
Resolution:                    |       Keywords:                  
        Os:  Unknown/Multiple  |   Architecture:  Unknown/Multiple
   Failure:  None/Unknown      |     Difficulty:  Unknown         
  Testcase:                    |      Blockedby:                  
  Blocking:                    |        Related:                  
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Comment(by jeltsch):

 Replying to [comment:78 igloo]:
 > The lexer complexity is only an issue with the `\ case` syntax, not with
 either `\ of` or `case of`, right?
 >
 > So given opinion seems to be divided on which is aesthetically nicer,
 which don't we implement one of the syntaxes that gives a simpler, cleaner
 specification and implementation?

 It’s not just about aesthetics, specification, and implementation. The
 {{{case of}}} solution has the problem that it cannot be carried over to
 arrow expressions. So we have the following situation:

   {{{case of}}}::
     no analog for arrow expressions
   {{{\case}}}::
     lexer complexity
   {{{\of}}}::
     not immediately visible that it is about case distinction

 I tend to prefer {{{\of}}}.

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/4359#comment:79>
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