patch applied (ghc): Various cleanups and improvements to the breakpoint support

[Simon Marlow]

Wed Apr 18 04:47:00 PDT 2007  Simon Marlow <simonmar at microsoft.com>
  * Various cleanups and improvements to the breakpoint support
  
    - move parts of the debugger implementation below the GHC API where
      they belong.  There is still more in Debugger that violates the
      layering, hopefully I'll get to that later.
  
    - instead of returning an IO action from runStmt for resuming,
      return a ResumeHandle that is passed to GHC.resume.
  
    - breakpoints now return [Name] which is displayed in the same
      way as when a binding statement is executed.
  
    - :load, :add, :reload now clear the active breakpoints and context
  
    - :break gives a sensible error when used on a non-interpreted module
  
    - export breakpoint-related types from GHC
  
    - remove a bunch of layer-violating imports from InteractiveUI
  
    - remove some more vestiges of the old breakpoint code (topLevel in
      the GHCi state).
  
    - remove TickTree and use a simple array instead, cached per module

    M ./compiler/basicTypes/SrcLoc.lhs -1 +3
    M ./compiler/deSugar/Coverage.lhs -15 +20
    M ./compiler/ghci/ByteCodeGen.lhs -1 +1
    M ./compiler/ghci/Debugger.hs -52 +11
    M ./compiler/ghci/GhciMonad.hs -22 +24
    M ./compiler/ghci/InteractiveUI.hs -123 +124
    R ./compiler/ghci/TickTree.hs
    M ./compiler/main/GHC.hs -77 +121
    M ./compiler/main/HscTypes.lhs -7 +11