[Gm2] ISO constant literal constructors implemented

[Gaius Mulley]

Hi,

I've just checked in the following changes which as the title suggests
implements ISO constant literal constructors.  This should allow
sets, records and arrays to be initialised via a constant declaration.
So for example here is the test code found in
testsuite/gm2/iso/pass/constructor4.mod:

MODULE constructor4 ;

TYPE
   colours = (red, green, blue) ;

   position = RECORD
                 x1, y1, x2, y2: CARDINAL ;
              END ;

   rec = RECORD
            col: colours;
            pos: position ;
         END ;

CONST
   first = rec{green, position{2,3,4,5}} ;

VAR
   second: rec ;
BEGIN
   second := first
END constructor4.


and the ChangeLog follows:

        * ISO conformant compound literal constructors have been
          implemented.
        * gm2/TODO:  updated.
        * gm2/gccgm2.c:  added constructor type and build
          functions to create ARRAY, RECORD and SET compound
          constructors.
        * gm2/bnf/m2-2.bnf:  modified grammer to include compound
          constructors and associated type build functions.  Limited
          compound literal type checking is also implemented.
        * gm2/bnf/m2-3.bnf:  modified grammer to include compound
          constructors and to appropriate quadruple generation.
        * gm2/bnf/m2-h.bnf:  modified grammer to include compound
          constructors during the hidden pass.
        * gm2/gm2/bnf/m2.bnf:  modified grammer to include compound
          constructors.
        * gm2/FifoQueue.def:  extended to allow enumerations and
          subranges to be stored and retrieved.
        * gm2/FifoQueue.mod:  implemented appropriately.
        * gm2/gm2-compiler/M2ALU.def:  major alterations to allow
          constructors (ARRAY, RECORD and SET) constants to be
          created at compile time and also be translated into GCC trees.
        * gm2/gm2-compiler/M2ALU.mod:  implemented above, more checking
          to ensure that a RECORDs and ARRAYs cannot have bits included.
          SETs cannot have fields initialized etc.
        * gm2/gm2-compiler/M2GCCDeclare.mod:  resolves all dependants
          of compound literals and declares Modula-2 constructors to
          their gcc tree counterpart.
        * gm2/gm2-compiler/M2Quads.def:  BuildConstructorStart,
          BuildConstructorEnd, CollectConstructor, BuildComponentValue
          added.
        * gm2/gm2-compiler/M2Quads.mod:  BuildConstructorStart,
          BuildConstructorEnd, CollectConstructor, BuildComponentValue,
          AddFieldTo implemented.
        * gm2/gm2-compiler/P1SymBuild.mod:  use
          PutEnumerationIntoFifoQueue.
        * gm2/gm2-compiler/P2SymBuild.mod:  use
          GetEnumerationFromFifoQueue and PutSubrangeInfoFifoQueue.
          Implement constructor type checking and add error messages.
          Implement constructor symbol creation.
        * gm2/gm2-compiler/P3SymBuild.mod:  use
          GetSubrangeFromFifoQueue.
        * gm2/gm2-compiler/SymbolTable.def:  export IsConstructor
          and PutConstructor.
        * gm2/gm2-compiler/SymbolTable.mod:  add IsConstructor
          field to SymConstVar and SymConstLit record in symbol
          table.  Implement procedures IsConstructor and
          PutConstructor.
        * gm2/gm2-compiler/gccgm2.def:  declare and export
          new versions of BuildStartSetConstructor,
          BuildSetConstructorElement, BuildEndSetConstructor.
          Also export BuildStartRecordConstructor,
          BuildEndRecordConstructor, BuildRecordConstructorElement,
          BuildStartArrayConstructor, BuildEndArrayConstructor and
          BuildArrayConstructorElement.  Also export Constructor
          hidden type.

regards,
Gaius