[GHC] #4316: Interactive "do" notation in GHCi

[GHC]

#4316: Interactive "do" notation in GHCi
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    Reporter:  mitar             |        Owner:  vivian      
        Type:  feature request   |       Status:  patch       
    Priority:  normal            |    Milestone:  7.2.1       
   Component:  GHCi              |      Version:  6.12.3      
    Keywords:                    |     Testcase:              
   Blockedby:                    |   Difficulty:              
          Os:  Unknown/Multiple  |     Blocking:              
Architecture:  Unknown/Multiple  |      Failure:  None/Unknown
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Comment(by vivian):

 Replying to [comment:14 simonmar]:
 > The basic idea is this: when we get a line of input from the user, we
 call the lexer in "alternative layout rule mode" to read tokens up to the
 end of the line, and then inspect the state of the lexer at that point.

 I add {{{Opt_AlternativeLayoutRule}}} as a dynamic flag.  I'm checking to
 see if the list of ALRContexts is empty and whether an opening curly brace
 is expected but this does not appear to be sufficient.  What in the "state
 of the lexer" should I be checking?

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/4316#comment:19>
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