[GHC] #3217: Make GHCi have separate flags for interactive Haskell expressions

[GHC]

#3217: Make GHCi have separate flags for interactive Haskell expressions
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    Reporter:  simonpj           |        Owner:                  
        Type:  feature request   |       Status:  new             
    Priority:  normal            |    Milestone:  6.12 branch     
   Component:  Compiler          |      Version:  6.10.2          
    Severity:  normal            |   Resolution:                  
    Keywords:                    |   Difficulty:  Unknown         
    Testcase:                    |           Os:  Unknown/Multiple
Architecture:  Unknown/Multiple  |  
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Comment (by claus):

 > > (eg., I'd be tempted to classify `:m +*Data.Map +*Data.IntMap` as an
 error, even if the source are available, on the rationale that `:m +mod`
 means `import` while `:m +*mod` means `include`).
 >
 > I'd be tempted to agree, although this is a fairly deep change.  The
 context is currently `([Module],[Module])`, this would mean changing it to
 `Either Module [Module]`, or perhaps `([Module], Maybe Module)`.

 I probably misunderstand your intentions there, but `([Module],[Module])`
 should be fine (assuming that this lists  `*`-ed and other modules
 separately), as long as only modules with compatible pragmas, defaults,
 and bindings can be added to the `*`-ed modules list. The
 `*Data.Map`/`*Data.IntMap` example would fail only because both define the
 same names (which is possible in `import`/`:m +mod`, but not in
 `include`/`:m +*mod`).

 > If we made this change, then I think it makes sense to take into account
 the flags and defaults of the "current" module.

 Thanks. I think I could live with only one `*`-ed module, if that was
 necessary to get this consistency, but there's no telling what wonderful
 uses other GHCi users have come up with, or what their preferences are..
 So permitting multiple `*`-ed modules sounds safer - just adding the
 requirement that they have to be compatible.

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/3217#comment:7>
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