[cvs-nhc98] patch applied (hat): --------------------------------------------------------------

[Malcolm Wallace]

Fri Jun 29 07:40:45 PDT 2001  malcolm
  * --------------------------------------------------------------
        Portability: preparation for moving the tracing transformation
                    to an early phase of the compiler.
                    ----------------------------------
  
  The tracing transformation will eventually move from its current
  position to be just after lexing/parsing.  This commit prepares the
  ground in various ways for that move.
  
    * There is a new "auxiliary" information file generated for every
      module.  Its extension is .hx, and it holds arity and fixity
      information for every exported identifier.  This means that
      imports must be chased to read .hx files (separate from the
      ordinary .hi file chasing).
  
    * There is a new type TraceId, which associates the current TokenId
      type with auxiliary information about arity and let/lambda-bound.
  
    * The new compiler flag -hx causes .hx information to be generated,
      and the abstract syntax tree to be completely relabelled from
      TokenIds to TraceIds.  (The relabelling also sorts out fixity,
      so that all ambiguous infix expressions are changed to simple
      applications.)
  
    * At the moment, with the -hx flag, the compiler simply pretty-prints
      the relabelled syntax tree and then stops.  The /plan/ is that the
      tracing transformation will take the relabelled tree as input
      and generate a new syntax tree, with the type dropped back down
      to simple TokenIds.  This tree could then either be pretty-printed
      for input to another compiler, or simply carried on through the
      normal nhc98 middle and back end.
  
  Issues still to be addressed:
  
    * The .hx information currently takes no account of qualified identifiers.
    * Class methods have no arity information.

    A ./src/compiler98/AuxFile.hs
    A ./src/compiler98/AuxFixity.hs
    A ./src/compiler98/AuxLabelAST.hs
    M ./src/compiler98/Flags.hs -4 +7
    M ./src/compiler98/Main.hs -14 +30
    M ./src/compiler98/Makefile -1 +2
    M ./src/compiler98/OsOnly.hs +2
    M ./src/compiler98/PrettySyntax.hs -7 +30
    A ./src/compiler98/TraceId.hs
    A ./src/hattrans/AuxFile.hs
    A ./src/hattrans/AuxFixity.hs
    A ./src/hattrans/AuxLabelAST.hs
    M ./src/hattrans/Flags.hs -4 +7
    A ./src/hattrans/TraceId.hs