[GHC] #8047: Implement line-number %-substitution for prompt-string

[GHC]

#8047: Implement line-number %-substitution for prompt-string
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        Reporter:  hvr               |            Owner:
            Type:  feature request   |           Status:  new
        Priority:  normal            |        Milestone:  7.8.1
       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):

 Additional note: there's a line-number counting bug in GHCi when multi-
 line input is involved independent of this patch; as you can see in the
 following example, GHCi seems to use a wrong line-number offset when
 evaluating multi-line input:

 {{{
 λ> :set prompt "\955:%l> "
 λ:3> :set prompt2 ":%l| "
 λ:4> :{
 :5| let x = ()
 :6|
 :7|     y = ()
 :8|     z = ()
 :9|
 :10|     x = ()
 :11| :}

 <interactive>:11:5:
     Conflicting definitions for ‛x’
     Bound at: <interactive>:11:5
               <interactive>:16:5
 λ:12> x

 <interactive>:12:1: Not in scope: ‛x’
 λ:13> x

 <interactive>:13:1: Not in scope: ‛x’
 λ:14>

 }}}

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8047#comment:1>
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