FishMarket 1.0/FishMarket v1.0.iso/fishies/501-525/disk_503/pcq/pcq12asc.lzh/Source/Declarations.p

Text File | 1991-06-08 | 17KB | 741 lines

External;

{
    Declarations.p (of PCQ Pascal)
    Copyright (c) 1989 Patrick Quaid

    Generally speaking, this module handles the various
declarations.  The major exception to this is doblock(), in main.p,
which might be considered a declaration.
}

{$O-}
{$I "Pascal.i"}

    Function EnterStandard(    st_Name : String;
                st_Object : IDObject;
                st_Type : TypePtr;
                st_Storage : IDStorage;
                st_Offset : Integer) : IDPtr;
        external;
    Function EnterSpell(Str : String) : String;
        external;
    Function Match(i : Symbols): boolean;
        external;
    Procedure Error(s : string);
        external;
    Function ConExpr(VAR ConType : TypePtr): Integer;
        external;
    Function AddType(at_Object : TypeObject;
             at_SubType : TypePtr;
             at_Ref : Address;
             at_Upper,
             at_Lower,
             at_Size : Integer) : TypePtr;
        external;

    procedure ns;
        external;
    Function TypeCmp(f, s : TypePtr): Boolean;
        external;
    Function FindID(s: string): IDPtr;
        external;
    function CheckID(s : string): IDPtr;
        external;
    Function CheckIDList(s : String; ID : IDPtr) : Boolean;
        external;
    Procedure EnterID(EntryBlock : BlockPtr; ID : IDPtr);
        external;
    procedure NextSymbol;
        external;
    Procedure NeedLeftParent;
        External;
    procedure NeedRightParent;
        external;
    Procedure Mismatch;
        External;
    Procedure DumpLitQ(Start : Integer);
        External;
    Procedure WriteHex(num : Integer);
        External;
    Function TypeCheck(T1, T2 : TypePtr) : Boolean;
        External;
    Function GetLabel : Integer;
        External;
    Function Suffix(Size : Integer) : Char;
        External;
    Procedure PrintLabel(lab : Integer);
        External;


Function DeclVar(ob : IDObject) : IDPtr;
    forward;

Procedure ReformArgs(ProcID : IDPtr);

{
    This is the first in a series of routines that assigns the
proper addresses to procedure or function arguments.
}

var
    TotalSize    : Integer;
    ID        : IDPtr;
begin
    ID := ProcID^.Param;
    if ProcID^.Level = 1 then
    TotalSize := 8
    else
    TotalSize := 12;
    While ID <> Nil do begin
    if ID^.Object = ValArg then begin
        TotalSize := TotalSize + ID^.VType^.Size;
        if Odd(TotalSize) then
        TotalSize := Succ(TotalSize);
    end else
        TotalSize := TotalSize + 4;
    ID := ID^.Next;
    end;
    ID := ProcID^.Param;
    while ID <> Nil do begin
    if ID^.Object = ValArg then begin
        TotalSize := TotalSize - ID^.VType^.Size;
        if Odd(TotalSize) then begin
        if ID^.VType^.Size = 1 then begin
            ID^.Offset := TotalSize;
            TotalSize := Pred(TotalSize);
        end else begin
            TotalSize := Pred(TotalSize);
            ID^.Offset := TotalSize;
        end;
        end else
        ID^.Offset := TotalSize;
    end else begin { RefArg }
        TotalSize := TotalSize - 4;
        ID^.Offset := TotalSize;
    end;
    ID := ID^.Next;
    end;
end;

Function ReformFields(ID : IDPtr) : Integer;

{
    ...Determines the proper offsets of the fields, and returns the
total size of the record.
}
var
    TotalSize : Integer;
begin
    TotalSize := 0;
    while ID <> Nil do begin
    if Odd(TotalSize) and (ID^.VType^.Size <> 1) then
        TotalSize := Succ(TotalSize);
    ID^.Offset := TotalSize;
    TotalSize := TotalSize + ID^.VType^.Size;
    ID := ID^.Next;
    end;
    ReformFields := TotalSize;
end;

Function GetRange() : TypePtr;
var
    TP        : TypePtr;
    IndexType1,
    IndexType2    : TypePtr;
    Hold,
    Lo, Hi    : Integer;
begin
    New(TP);
    TP^.Object := ob_subrange;
    Lo := ConExpr(IndexType1);
    if not Match(DotDot1) then
    error("expecting '..' here");
    Hi := ConExpr(IndexType2);
    if not TypeCheck(IndexType1, IndexType2) then begin
    Error("Incompatible range types");
    IndexType1 := BadType;
    end;
    if Lo > Hi then begin
    Error("Lower bound greater than upper bound");
    Hold := Hi;
    Hi := Lo;
    Lo := Hold;
    end;
    GetRange := AddType(ob_subrange, IndexType1, IndexType1,
            Hi, Lo, IndexType1^.Size);
end;

Function DeclArgs(ob : IDObject) : IDPtr;
    forward;

Function ReadRecord(): TypePtr;

{
    This just reads a record.
}
var
    Size   : Integer;
    TP     : TypePtr;
begin
    TP := AddType(ob_record, Nil, Nil, 0, 0, 0);
    if TypeID <> Nil then
    TypeID^.VType := TP;
    TP^.Ref := DeclArgs(field);
    if not match(end1) then
    error("Missing END of record");
    TP^.Size := ReformFields(TP^.Ref);
    ReadRecord := TP;
end;

Function ReadEnumeration(): TypePtr;

{
    This just reads enumerations and assigns them numbers
starting with zero.  The size of an enumerated type is either 1
or two bytes: Enumerations with > 127 items are contained in 2.
}

var
    Position : Integer;
    EnumType : TypePtr;
    ID         : IDPtr;
begin
    Position := 0;
    EnumType := AddType(ob_ordinal, Nil, Nil, 0, 0, 0);
    While CurrSym = Ident1 do begin
    if CheckID(SymText) <> Nil then
        Error("Duplicate ID");
    ID := EnterStandard(SymText, constant, EnumType, st_none, Position);
    Position := Succ(Position);
    NextSymbol;
    if CurrSym <> RightParent1 then
        if not Match(Comma1) then
        Error("Missing Comma");
    end;
    if Position <= 256 then    { Position = # of enumerations + 1 }
    EnumType^.Size := 1
    else
    EnumType^.Size := 2;
    NeedRightParent;
    ReadEnumeration := EnumType;
end;

    Function ReadType : TypePtr;
    Forward;

Function DefineArray : TypePtr;
var
    TP, TP2,
    LastType : TypePtr;
    ID : IDPtr;

    Function DeclareDimension : TypePtr;
    var
    TP : TypePtr;
    begin
    TP := GetRange;
    with TP^ do begin
        Ref := SubType;
        Object := ob_array;
        if Match(Comma1) then
        SubType := DeclareDimension
        else
        SubType := Nil;
    end;
    DeclareDimension := TP;
    end;

    Procedure FixArraySize(TP : TypePtr);
    begin
    if TP^.Object = ob_array then begin
        FixArraySize(TP^.SubType);
        TP^.Size := TP^.SubType^.Size * (TP^.Upper - TP^.Lower + 1);
    end;
    end;

begin
    if Match(LeftBrack1) then begin
    TP := DeclareDimension;
    LastType := TP;
    While LastType^.SubType <> Nil do
        LastType := LastType^.SubType;   { Get the last array dim }
    if not Match(RightBrack1) then
        error("Expecting a right bracket");
    end else if CurrSym = Ident1 then begin
    ID := FindID(SymText);
    NextSymbol;
    if ID = Nil then begin
        error("Unknown ID");
        TP := BadType;
    end else if ID^.Object <> obtype then begin
        error("Expecting a type");
        TP := BadType;
    end else if ID^.VType^.Object <> ob_subrange then begin
        error("Expecting a range");
        TP := BadType;
    end else
        TP := ID^.VType;
    New(TP2);
    TP2^ := TP^;
    TP := TP2;
    TP^.Next := CurrentBlock^.FirstType;
    CurrentBlock^.FirstType := TP;
    LastType := TP;
    end else begin
    error("Expecting range");
    New(TP);
    TP^ := BadType^;
    LastType := TP;
    end;
    TP^.Object := ob_array;
    if not match(of1) then
    error("expecting OF");
    LastType^.SubType := ReadType;
    FixArraySize(TP);
    DefineArray := TP;
end;

Function ReadType(): TypePtr;

{
    This routine creates and returns a type record produced
by a normal type declaration.  Note that this function is used
almost everywhere a type is called for, so you can use a full type
description in most places.
}

var
    TP    : TypePtr;
    ID  : IDPtr;
    Length : Integer;
begin
    if currsym = ident1 then begin
    ID := FindID(symtext);
    if ID = Nil then begin
        Error("Unknown ID");
        TP := BadType;
        NextSymbol;
    end else if ID^.Object = obtype then begin
        TP := ID^.VType;
        NextSymbol;
     {   if Match(LeftBrack1) and (TP = StringType) then begin
        Length := ConExpr(TP);
        if TypeCheck(TP,IntType) then begin
            if Length < 0 then
            Error("String length must be positive");
            TP := AddType(ob_prestring, CharType, Nil, Pred(Length), 0, Length);
        end else begin
            Error("Expecting an integer length");
            TP := BadType;
        end;
        if not Match(RightBrack1) then
            Error("Missing ]");
        end; }
    end else if ID^.Object = constant then
        TP := GetRange()
    else begin
        Error("Expecting a TYPE");
        TP := BadType;
        NextSymbol;
    end;
    end else if (CurrSym = Numeral1) or (CurrSym = Apostrophe1) then
    TP := GetRange()
    else if match(carat1) then begin
    TP := ReadType();
    TP := AddType(ob_pointer, TP, nil, 0, 0, 4);
    end else if match(leftparent1) then
    TP := ReadEnumeration()
    else if match(array1) then
    TP := DefineArray
    else if match(record1) then begin
    TP := ReadRecord();
    end else if match(file1) then begin
    if not match(of1) then
        error("expecting OF");
    TP := ReadType();
    TP := AddType(ob_file, TP, nil, TP^.Size, 0, 32);
    end else begin
    error("unknown type of thing");
    TP := BadType;
    end;
    readtype := TP;
end;

Procedure DeclType;

{
    This handles a type declaration block.
}
begin
    While CurrSym = ident1 do begin
    if CheckID(SymText) <> nil then
        error("duplicate id");
    TypeID := EnterStandard(SymText, obtype, BadType, st_none, 0);
    NextSymbol;
    if not Match(equal1) then
        Error("expecting '=' here");
    TypeID^.VType := ReadType();
    ns;
    end;
    TypeID := Nil;
end;

Function DeclArgs(ob : IDObject) : IDPtr;

    Procedure DeclArgList(var VarList : IDPtr; ob : IDObject);
    var
    ID,
    RunID : IDPtr;
    begin
    if CurrSym = Ident1 then begin
        if CheckIDList(SymText, VarList) then
        error("Duplicate Parameter Name");
        New(ID);
        ID^.Name := EnterSpell(SymText);
        ID^.Object := ob;
        ID^.Next := Nil;
        if VarList = Nil then
        VarList := ID
        else begin
        RunID := VarList;
        while RunID^.Next <> Nil do
            RunID := RunID^.Next;
        RunID^.Next := ID;
         end;
        NextSymbol;
        if Match(Comma1) then begin
        DeclArgList(VarList, ob);
        ID^.VType := ID^.Next^.VType;
        end else begin
        if not Match(colon1) then
            error("Expecting a colon");
        ID^.VType := ReadType();
        end;
        if (ob = valarg) and (ID^.VType^.Object = ob_file) then
        error("Files must be VAR parameters");
    end;
    end;

var
    ID : IDPtr;

begin
    ID := Nil;
    if ob = field then begin
    While CurrSym = Ident1 do begin
        DeclArgList(ID, field);
        ns;
    end;
    end else begin
    while (CurrSym = Ident1) or (CurrSym = Var1) do begin
        if Match(Var1) then
        DeclArgList(ID, refarg)
        else
        DeclArgList(ID, valarg);
        if CurrSym <> RightParent1 then
        ns;
    end;
    end;
    DeclArgs := ID;
end;

Function DeclVar(ob : IDObject) :  IDPtr;

{
    This is used to declare a local or global variable.
}

var
    ID,
    NextID : IDPtr;
    TP    : TypePtr;
begin
    if currsym = ident1 then begin
    if CheckID(symtext) <> Nil then
        error("Duplicate id");
    ID := EnterStandard(symtext, ob, BadType, StandardStorage, 0);
    NextSymbol;
    if match(comma1) then begin
        NextID := DeclVar(ob);
        ID^.VType := NextID^.VType;
    end else begin
        if not match(colon1) then
        error("expecting :");
        ID^.VType := ReadType();
    end;
    if ob = local then begin
        StackSpace := StackSpace + ID^.VType^.Size;
        if Odd(StackSpace) and (ID^.VTYpe^.Size <> 1) then
        StackSpace := Succ(StackSpace);
        ID^.Offset := -StackSpace;
    end;
    end else begin
    error("expecting an identifier");
    if CurrSym = Colon1 then
        TP := ReadType()
    else if match(colon1) then
        TP := ReadType();
    end;
    DeclVar := ID;
end;

Procedure VarDeclarations;

{
    This handles a variable declaration block.
}
var
    ID    : IDPtr;
begin
    While CurrSym = ident1 do begin
    if CurrentBlock^.Level = 1 then begin
        ID := DeclVar(global);
        ns;
    end else begin
        ID := DeclVar(local);
        ns;
    end;
    end;
end;

Function TypedConstant(TP : TypePtr) : Integer;
var
    DefineIt : Boolean;

    Function TypedOrdinal(TP : TypePtr) : Integer;
    var
    ExprType : TypePtr;
    ExprVal  : Integer;
    begin
    ExprVal := ConExpr(ExprType);
    if DefineIt then
        Writeln(OutFile, '\tdc.', Suffix(TP^.Size), '\t', ExprVal);
    if not TypeCheck(ExprType, TP) then
        Mismatch;
    TypedOrdinal := ExprVal;
    end;

    Function TypedArray(TP : TypePtr) : Integer;
    var
    ExprType : TypePtr;
    ExprVal  : Integer;
    Column   : Short;
    Current  : Integer;
    begin
    if TypeCheck(TP^.SubType, CharType) then begin { special }
        ExprVal := ConExpr(ExprType);
        if not TypeCheck(ExprType, TP) then
        MisMatch;
        if DefineIt then
        DumpLitQ(ExprVal);
        LitPtr := ExprVal;
        TypedArray := 1;
    end else if TP^.SubType^.Object = ob_ordinal then begin
        NeedLeftParent;
        Column := 0;
        if DefineIt then
        Write(OutFile, '\tdc.', Suffix(TP^.SubType^.Size), '\t');
        for Current := 1 to TP^.Upper - TP^.Lower + 1 do begin
        ExprVal := ConExpr(ExprType);
        if not TypeCheck(ExprType, TP^.SubType) then
            Mismatch;
        if DefineIt then begin
            if Column > 60 then begin
            Write(OutFile, '\n\tdc.', Suffix(TP^.SubType^.Size), '\t');
            Column := 0;
            end;
            if Column > 0 then
            Write(OutFile, ',');
            Write(OutFile, ExprVal);
            Column := Column + ExprType^.Size * 3;
        end;
        if CurrSym <> RightParent1 then
            if not Match(Comma1) then
            Error("Expecting a comma");
        end;
        if DefineIt then
        Writeln(OutFile);
        NeedRightParent;
        TypedArray := 1;
    end else begin
        NeedLeftParent;
        for Current := 1 to TP^.Upper - TP^.Lower + 1 do begin
        ExprVal := TypedConstant(TP^.SubType);
        if CurrSym <> RightParent1 then
            if not match(Comma1) then
            Error("Expecting a comma");
        end;
        NeedRightParent;
        TypedArray := 1;
    end;
    end;

    Function TypedPointer(TP : TypePtr) : Integer;
    var
    ID : IDPtr;
    ExprVal : Integer;
    ExprType : TypePtr;
    begin
    if Match(At1) then begin
        if CurrSym = Ident1 then begin
        ID := FindID(SymText);
        if ID <> Nil then begin
            if (ID^.Object = Global) or
            (ID^.Object = typed_const) then begin
            if DefineIt then begin
                if ID^.Level <= 1 then
                Writeln(OutFile, '\tdc.l\t_', ID^.Name)
                else
                Writeln(OutFile, '\tdc.l\t_', ID^.Name,
                        '%', ID^.Unique);
            end;
            if not TypeCheck(TP^.SubType, ID^.VType) then
                MisMatch;
            end else
            Error("Expecting a global identifier");
            NextSymbol;
        end else
            Error("Unknown ID");
        end else
        Error("Expecting an identifier");
        TypedPointer := 1;
    end else begin
        ExprVal := ConExpr(ExprType);
        if not TypeCheck(ExprType, TP) then
        Mismatch;
        if DefineIt then begin
        if ExprType = StringType then begin
            Write(OutFile, '\tdc.l\t');
            PrintLabel(LitLab);
            Writeln(OutFile, '+', ExprVal);
        end else
            Writeln(OutFile, '\tdc.l\t', ExprVal);
        end else
        LitPtr := ExprVal;
        TypedPointer := ExprVal;
    end;
    end;

    Function TypedRecord(TP : TypePtr) : Integer;
    var
    ID : IDPtr;
    ExprVal : Integer;
    begin
    NeedLeftParent;
    ID := TP^.Ref;
    while ID <> Nil do begin
        ExprVal := TypedConstant(ID^.VType);
        ID := ID^.Next;
        if ID <> Nil then
        if not Match(Comma1) then
            Error("Expecting a comma");
    end;
    NeedRightParent;
    TypedRecord := 1;
    end;

    Function TypedReal : Integer;
    var
    ExprVal : Integer;
    ExprType : TypePtr;
    begin
    ExprVal := ConExpr(ExprType);
    if not TypeCheck(ExprType, RealType) then
        MisMatch;
    if DefineIt then begin
        Write(OutFile, '\tdc.l\t');
        WriteHex(ExprVal);
        Writeln(OutFile);
    end;
    TypedReal := ExprVal;
    end;

begin
    DefineIt := StandardStorage <> st_external;
    case TP^.Object of
    ob_ordinal,
    ob_subrange : TypedConstant := TypedOrdinal(TP);
    ob_array   : TypedConstant := TypedArray(TP);
    ob_pointer : TypedConstant := TypedPointer(TP);
    ob_record  : TypedConstant := TypedRecord(TP);
    ob_real    : TypedConstant := TypedReal;
    else
    Error("No typed constants allowed for this type");
    end;
end;

Procedure DeclConst;

{
    This handles a const declaration block.  The grunt work is
does by conexpr() in expression.p, which is the routine to look at
if you want to improve constant declarations.
}
var
    ID : IDPtr;
    BackName : String;
    TP : TypePtr;
begin
    While CurrSym = Ident1 do begin
    if CheckID(SymText) <> Nil then
        Error("Duplicate ID");
    ID := EnterStandard(SymText, constant, Nil, st_none, 0);
    BackName := ID^.Name;
    ID^.Name := "";    { So the ID can't be used in the expression }
    NextSymbol;
    if Match(Colon1) then begin
        ID^.VType := ReadType;
        if not Match(Equal1) then
        Error("Missing =");
        if StandardStorage <> st_external then begin
        if ID^.VType^.Size > 1 then
            Writeln(OutFile, '\tCNOP\t0,2');
        if CurrentBlock^.Level <= 1 then begin
            if StandardStorage <> st_private then
            Writeln(OutFile, '\tXDEF\t_', BackName);
            writeln(OutFile, '_', BackName)
        end else begin
            ID^.Unique := GetLabel;
            writeln(OutFile, '_', BackName, '%', ID^.Unique);
        end;
        end;
        ID^.Offset := TypedConstant(ID^.VType);
        ID^.Name := BackName;
        ID^.Object := typed_const;
        if StandardStorage <> st_external then
        ID^.Storage := st_initialized
        else
        ID^.Storage := st_external;
    end else begin
        if not Match(Equal1) then
        Error("Expecting =");
        ID^.Offset := ConExpr(TP);
        ID^.VType := TP;
        ID^.Name := BackName;
    end;
    ns;
    end;
end;

Procedure DeclLabel;
{
    This routine accepts a list of identifiers to be used as
    labels in the program.  Standard Pascal's labels are four
    digit numbers, but I didn't want to mess with that.
}
var
    ID : IDPtr;
begin
    while CurrSym = Ident1 do begin
    ID := EnterStandard(SymText, lab, Nil, st_none, 0);
    ID^.Unique := GetLabel;
    NextSymbol;
    if not Match(Comma1) then begin
        ns;
        return;
    end;
    end;
    Error("Expecting an identifier");
end;