[GHC] #8051: GHCi: confusing `:set +m`/`:{` interaction & wrong line-numbers in multi-line input

[GHC]

#8051: GHCi: confusing `:set +m`/`:{` interaction & wrong line-numbers in multi-
line input
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        Reporter:  hvr               |            Owner:
            Type:  bug               |           Status:  new
        Priority:  normal            |        Milestone:
       Component:  GHCi              |          Version:  7.6.3
      Resolution:                    |         Keywords:
Operating System:  Unknown/Multiple  |     Architecture:  Unknown/Multiple
 Type of failure:  None/Unknown      |       Difficulty:  Unknown
       Test Case:                    |       Blocked By:
        Blocking:                    |  Related Tickets:
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Comment (by hvr):

 Btw, here's a minor fixlet for HEAD, which doesn't honor `prompt2` for
 `:set +m` multi-line input:

 {{{
 #!diff
 diff --git a/ghc/InteractiveUI.hs b/ghc/InteractiveUI.hs
 index 4bac5ad..7b10b65 100644
 --- a/ghc/InteractiveUI.hs
 +++ b/ghc/InteractiveUI.hs
 @@ -790,7 +790,7 @@ checkInputForLayout stmt getStmt = do
       _other              -> do
         st1 <- lift getGHCiState
         let p = prompt st1
 -       lift $ setGHCiState st1{ prompt = "%s| " }
 +       lift $ setGHCiState st1{ prompt = prompt2 st1 }
         mb_stmt <- ghciHandle (\ex -> case fromException ex of
                              Just UserInterrupt -> return Nothing
                              _ -> case fromException ex of
 }}}

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8051#comment:1>
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