[_CD6_]<dragon>Modula>M2QImpl.mesa!1

FILE: M2QImpl.mesa

Modula-2 Parser, Part 2

Last Edited by: Gutknecht, September 19, 1985 3:21:10 am PDT

DIRECTORY

M2D USING [StrForm, ObjPtr, ConstPtr, VarPtr, ProcPtr, CodePtr, FieldPtr, StrPtr, EnumPtr, RangePtr, SetPtr, PointerPtr, ProcTypPtr, ArrayPtr, RecordPtr, ParPtr, WordSize, Proc, undftyp, notyp, inttyp, cardtyp, dbltyp, realtyp, bitstyp, chartyp, stringtyp, UNION],

M2F USING [GenStParam, GenStFct],

M2G USING [LabelTabPtr, LabelTable, NofCases, GenItem, GenSingSet, GenSet, GenTrap, GenIndex, GenField, GenDeRef, PrepCall, GenCall, GenParam],

M2H USING [ItemPtr, Item, LoadAdr, Load, LoadStk, GenIn, GenOp, GenNeg, GenNot, GenAnd, GenOr],

M2I USING [pc, AllocString],

M2S USING [Symbol, sym, numtyp, intval, dblval, realval, id, GetSym, KeepId, Mark],

M2T USING [Scope, LastObj, NewScope, NewObj, NewStr, NewPar, CloseScope, ParamLink, Find, FindExport, FindField],

M2Q;

M2QImpl: CEDAR PROGRAM

IMPORTS M2D, M2F, M2G, M2H, M2I, M2S, M2T

EXPORTS M2Q =

BEGIN OPEN M2Q;

MaxInt: CARDINAL = 77777B;

EnumTypSize : CARDINAL = 1;

SetTypSize: CARDINAL = 1;

PointerTypSize: CARDINAL = 1;

ProcTypSize: CARDINAL = 1;

DynArrDesSize: CARDINAL = 2;

dummyContxt: M2D.ProcPtr ← NEW [M2D.Proc ← [cell: 2]];

InitQ: PUBLIC PROC = {};

err: PROC [n: CARDINAL] = { M2S.Mark [n] };

CheckSym: PROC [s: M2S.Symbol, n: CARDINAL] =

{ IF M2S.sym = s THEN M2S.GetSym ELSE M2S.Mark [n] };

qualident: PROC RETURNS [obj: M2D.ObjPtr] =

{ -- sym = ident --

obj ← M2T.Find [M2S.id];

M2S.GetSym;

WHILE (M2S.sym = period) AND (obj # NIL) AND (obj^.class = Module) DO

M2S.GetSym;

IF M2S.sym = ident THEN

{ obj ← M2T.FindExport [M2S.id, NARROW [obj^.ext]]; M2S.GetSym }

ELSE err [10]

ENDLOOP };

CheckComp: PROC [t0, t1: M2D.StrPtr] =

{ IF (t0 # t1) AND ((t0 # M2D.inttyp) OR (t1 # M2D.cardtyp)) THEN err [61] };

CaseLabelList: PUBLIC PROC [Ltyp: M2D.StrPtr, n: CARDINAL, tab: M2G.LabelTabPtr] RETURNS [N: CARDINAL] =

{ x: M2H.ItemPtr ← NEW [M2H.Item];

y: M2H.ItemPtr ← NEW [M2H.Item];

f: M2D.StrForm ← Ltyp^.form;

IF f = Range THEN

{ range: M2D.RangePtr ← NARROW [Ltyp^.ext]; Ltyp ← range^.BaseTyp }

ELSE

IF (f > Int) AND (f # Enum) THEN err [38];

DO ConstExpression [x]; CheckComp [Ltyp, x.typ];

IF M2S.sym = ellipsis THEN

{ M2S.GetSym; ConstExpression [y]; CheckComp [Ltyp, y.typ] }

ELSE y^ ← x^;

enter label range into ordered table --

IF n < M2G.NofCases THEN { i: CARDINAL ← n;

IF i = 0 THEN EXIT;

IF tab[i-1].low <= y.val.I THEN

{ IF tab[i-1].high >= x.val.I THEN err [62];

EXIT };

tab[i] ← tab[i-1]; i ← i-1

ENDLOOP;

tab[i].low ← x.val.I; tab[i].high ← y.val.I; tab[i].label ← M2I.pc;

n ← n + 1 }

ELSE err [92];

IF M2S.sym = comma THEN M2S.GetSym

ELSE

IF (M2S.sym >= lparen) AND (M2S.sym <= ident) THEN err [11]

ELSE EXIT

ENDLOOP;

N ← n };

FieldListSequence: PROC [adr: CARDINAL] RETURNS [maxAdr: CARDINAL] =

{fld0, fld1, tagfldtyp: M2D.ObjPtr; typ: M2D.StrPtr;

VariantPart: PROC =

{ tabPtr: M2G.LabelTabPtr ← NEW [M2G.LabelTable];

lastadr: CARDINAL; N: CARDINAL;

maxAdr ← adr; N ← 0;

IF M2S.sym < bar THEN

{ N ← CaseLabelList [typ, N, tabPtr]; CheckSym [colon, 13];

lastadr ← FieldListSequence [adr];

IF lastadr > maxAdr THEN maxAdr ← lastadr };

IF M2S.sym = bar THEN M2S.GetSym ELSE EXIT

ENDLOOP;

IF M2S.sym = else THEN

{ M2S.GetSym; lastadr ← FieldListSequence [adr];

IF lastadr > maxAdr THEN maxAdr ← lastadr }};

typ ← M2D.undftyp;

IF (M2S.sym = ident) OR (M2S.sym = case) THEN

IF M2S.sym = ident THEN

{ fld0 ← M2T.LastObj []; fld1 ← fld0;

IF M2S.sym = ident THEN

{ fld1 ← M2T.NewObj [M2S.id, Field]; M2S.KeepId; M2S.GetSym }

ELSE err [10];

IF M2S.sym = comma THEN M2S.GetSym

ELSE IF M2S.sym = ident THEN err [11]

ELSE EXIT

ENDLOOP;

CheckSym [colon, 13]; typ ← Type [];

WHILE fld0 # fld1 DO fld0 ← fld0^.next;

{ field: M2D.FieldPtr ← NARROW [fld0^.ext];

fld0^.typ ← typ; field^.offset ← adr };

adr ← adr + typ^.size

ENDLOOP }

ELSE IF M2S.sym = case THEN

{ M2S.GetSym; fld1 ← NIL; tagfldtyp ← NIL;

IF M2S.sym = ident THEN

{ fld1 ← M2T.NewObj [M2S.id, Field]; M2S.KeepId; M2S.GetSym };

CheckSym [colon, 13];

IF M2S.sym = ident THEN tagfldtyp ← qualident [] ELSE err [10];

IF (tagfldtyp # NIL) AND (tagfldtyp^.class = Typ) THEN typ ← tagfldtyp^.typ

ELSE err [52];

IF fld1 # NIL THEN

{ field: M2D.FieldPtr ← NARROW [fld1^.ext];

field^.offset ← adr; fld1^.typ ← typ; adr ← adr + typ^.size };

CheckSym [of, 23]; VariantPart; adr ← maxAdr;

CheckSym [end, 20] };

IF M2S.sym = semicolon THEN M2S.GetSym

ELSE IF M2S.sym = ident THEN err [12]

ELSE EXIT

ENDLOOP;

maxAdr ← adr };

SubRange: PROC RETURNS [typ: M2D.StrPtr] =

{ x: M2H.ItemPtr ← NEW [M2H.Item];

y: M2H.ItemPtr ← NEW [M2H.Item];

f: M2D.StrForm; range: M2D.RangePtr ← NIL;

typ ← M2T.NewStr [Range]; range ← NARROW [typ^.ext];

ConstExpression [x]; f ← x^.typ^.form;

IF (f <= Int) OR (f = Enum) THEN range^.min ← x^.val.I ELSE err [82];

CheckSym [ellipsis, 21]; ConstExpression [y]; CheckComp [x^.typ, y^.typ];

IF (y^.typ = M2D.cardtyp) AND (y^.val.C > MaxInt) THEN err [95];

range^.max ← y^.val.I;

IF range^.min > range^.max THEN err [63];

range^.BaseTyp ← x^.typ; typ^.size ← x^.typ^.size };

SimpleType: PROC RETURNS [typ: M2D.StrPtr] =

{ obj: M2D.ObjPtr; typ0: M2D.StrPtr; n: CARDINAL;

range: M2D.RangePtr ← NIL; enum: M2D.EnumPtr ← NIL;

typ ← M2D.undftyp;

IF M2S.sym = ident THEN { obj ← qualident [];

IF (obj # NIL) AND (obj^.class = Typ) THEN typ ← obj^.typ ELSE err [52];

IF M2S.sym = lbrak THEN { M2S.GetSym;

typ0 ← typ; typ ← SubRange []; range ← NARROW [typ^.ext];

IF range^.BaseTyp # typ0 THEN

IF (typ0 = M2D.inttyp) AND(range^.BaseTyp = M2D.cardtyp) THEN

range^.BaseTyp ← M2D.inttyp

ELSE err [61];

IF M2S.sym = rbrak THEN M2S.GetSym

ELSE

{ err [16]; IF M2S.sym = rparen THEN M2S.GetSym }}}

ELSE IF M2S.sym = lparen THEN { M2S.GetSym;

typ ← M2T.NewStr [Enum]; enum ← NARROW [typ^.ext];

obj ← NIL; n ← 0;

DO const: M2D.ConstPtr ← NIL;

IF M2S.sym = ident THEN

{ obj ← M2T.NewObj [M2S.id, Const]; M2S.KeepId;

const ← NARROW [obj^.ext]; const^.conval.C ← n;

n ← n + 1; obj^.typ ← typ;

M2S.GetSym }

ELSE err [10];

IF M2S.sym = comma THEN M2S.GetSym

ELSE IF M2S.sym = ident THEN err [11]

ELSE EXIT

ENDLOOP;

enum^.NofConst ← n; typ^.size ← EnumTypSize;

CheckSym [rparen, 15] }

ELSE IF M2S.sym = lbrak THEN

{ M2S.GetSym; typ ← SubRange [];

IF M2S.sym = rbrak THEN M2S.GetSym

ELSE { err [16];

IF M2S.sym = rparen THEN M2S.GetSym }}

ELSE err [32] };

FormalType: PUBLIC PROC RETURNS [typ: M2D.StrPtr] =

{ objtyp: M2D.ObjPtr; array: M2D.ArrayPtr ← NIL;

typ ← M2D.undftyp;

IF M2S.sym = array THEN { M2S.GetSym;

typ ← M2T.NewStr [Array]; array ← NARROW [typ^.ext];

typ^.strobj ← NIL; typ^.size ← DynArrDesSize; array^.dyn ← TRUE;

CheckSym [of, 23];

IF M2S.sym = ident THEN { objtyp ← qualident [];

IF (objtyp # NIL) AND (objtyp^.class = Typ) THEN

array^.ElemTyp ← objtyp^.typ

ELSE err [52] }

ELSE err [10] }

ELSE

IF M2S.sym = ident THEN

{ objtyp ← qualident [];

IF (objtyp # NIL) AND (objtyp^.class = Typ) THEN

typ ← objtyp^.typ

ELSE err [52] }

ELSE err [10] };

FormalTypeList: PROC [proctyp: M2D.ProcTypPtr] =

{ obj: M2D.ObjPtr; partyp: M2D.StrPtr; isvar: BOOLEAN;

IF (M2S.sym = ident) OR (M2S.sym = var) OR (M2S.sym = array) THEN

IF M2S.sym = var THEN { M2S.GetSym; isvar ← TRUE }

ELSE isvar ← FALSE;

partyp ← FormalType []; M2T.NewPar [partyp, isvar];

IF M2S.sym = comma THEN M2S.GetSym

ELSE IF M2S.sym = ident THEN err [11]

ELSE EXIT

ENDLOOP;

CheckSym [rparen, 15]; proctyp^.firstPar ← M2T.ParamLink [];

IF M2S.sym = colon THEN

{ M2S.GetSym; proctyp^.resTyp ← M2D.undftyp;

IF M2S.sym = ident THEN { obj ← qualident [];

IF (obj # NIL) AND (obj^.class = Typ) THEN proctyp^.resTyp ← obj^.typ

ELSE err [52] }

ELSE err [10] }

ELSE proctyp^.resTyp ← M2D.notyp };

ArrayType: PROC RETURNS [typ: M2D.StrPtr] =

{ a, b: INTEGER; array: M2D.ArrayPtr ← NIL;

typ ← M2T.NewStr [Array]; array ← NARROW [typ^.ext];

array^.dyn ← FALSE; a ← 0;

array^.IndexTyp ← SimpleType [];

IF array^.IndexTyp^.form = Range THEN

{ range: M2D.RangePtr ← NARROW [array^.IndexTyp^.ext];

a ← range^.min; b ← range^.max }

ELSE { err [94]; b ← 0 };

IF M2S.sym = of THEN { M2S.GetSym; array^.ElemTyp ← Type [] }

ELSE

IF M2S.sym = comma THEN { M2S.GetSym; array^.ElemTyp ← ArrayType [] }

ELSE { err [23]; array^.ElemTyp ← M2D.undftyp };

a ← b-a+1; b ← array^.ElemTyp^.size;

IF array^.ElemTyp^.form = Char THEN {}

ELSE

IF MaxInt / b >= a THEN a ← a*b

ELSE { err [210]; a ← 1 };

typ^.size ← a };

OpaqueType: PUBLIC PROC RETURNS [typ: M2D.StrPtr] =

{ typ ← M2T.NewStr [Opaque]; typ^.size ← PointerTypSize };

Type: PUBLIC PROC RETURNS [typ: M2D.StrPtr] =

{ obj: M2D.ObjPtr; btyp: M2D.StrPtr;

IF M2S.sym < lparen THEN { err [33];

DO M2S.GetSym;

IF M2S.sym >= lparen THEN EXIT

ENDLOOP };

IF M2S.sym = array THEN { M2S.GetSym; typ ← ArrayType [] }

ELSE IF M2S.sym = record THEN

{ record: M2D.RecordPtr ← NIL; M2S.GetSym;

typ ← M2T.NewStr [Record]; record ← NARROW [typ^.ext];

obj ← M2T.NewScope [Typ]; -- header --

typ^.size ← FieldListSequence [0];

record^.firstFld ← obj^.next;

CheckSym [end, 20];

M2T.CloseScope }

ELSE IF M2S.sym = set THEN

{ set: M2D.SetPtr ← NIL; M2S.GetSym; CheckSym [of, 23];

typ ← M2T.NewStr [Set]; set ← NARROW [typ^.ext];

set^.BaseTyp ← SimpleType []; btyp ← set^.BaseTyp;

IF btyp^.form = Enum THEN

{ enum: M2D.EnumPtr ← NARROW [btyp^.ext];

IF enum^.NofConst > M2D.WordSize THEN err [209] }

ELSE IF btyp^.form = Range THEN

{ range: M2D.RangePtr ← NARROW [btyp^.ext];

IF (range^.min < 0) OR (range^.max >= M2D.WordSize) THEN err [209] }

ELSE err [60];

typ^.size ← SetTypSize }

ELSE IF M2S.sym = pointer THEN

{ pointer: M2D.PointerPtr ← NIL; M2S.GetSym;

typ ← M2T.NewStr [Pointer]; pointer ← NARROW [typ^.ext];

pointer^.BaseId ← 0; typ^.size ← PointerTypSize;

CheckSym [to, 24];

IF M2S.sym = ident THEN { obj ← qualident [];

IF obj = NIL THEN

{ pointer^.BaseTyp ← M2D.undftyp; pointer^.BaseId ← M2S.id;

M2S.KeepId-- forward ref --}

ELSE

IF obj^.class = Typ THEN pointer^.BaseTyp ← obj^.typ ELSE err [52] }

ELSE pointer^.BaseTyp ← Type [] }

ELSE IF M2S.sym = procedure THEN

{ proctyp: M2D.ProcTypPtr; M2S.GetSym;

typ ← M2T.NewStr [ProcTyp]; proctyp ← NARROW[typ^.ext];

typ^.size ← ProcTypSize;

IF M2S.sym = lparen THEN { M2S.GetSym; FormalTypeList [proctyp] }

ELSE proctyp^.resTyp ← NIL }

ELSE typ ← SimpleType [];

IF (M2S.sym < semicolon) OR (M2S.sym > else) THEN { err [34];

WHILE (M2S.sym < ident) OR (M2S.sym > else) AND (M2S.sym < begin) DO

M2S.GetSym

ENDLOOP }};

Selector: PUBLIC PROC [x: M2H.ItemPtr, obj: M2D.ObjPtr] =

{ y: M2H.ItemPtr ← NEW [M2H.Item ← [contxt: x^.contxt]];

M2G.GenItem [x, obj, M2T.Scope];

IF M2S.sym = lbrak THEN { M2S.GetSym;

M2H.LoadAdr [x]; Expression [y]; M2G.GenIndex [x, y];

IF M2S.sym = comma THEN M2S.GetSym ELSE EXIT

ENDLOOP;

CheckSym [rbrak, 16] }

ELSE IF M2S.sym = period THEN { M2S.GetSym;

IF M2S.sym = ident THEN

{ IF (x^.typ # NIL) AND (x^.typ^.form = Record) THEN

{ obj ← M2T.FindField [M2S.id, NARROW[x^.typ^.ext]];

M2G.GenField [x, obj] }

ELSE err [57];

M2S.GetSym }

ELSE err [10] }

ELSE IF M2S.sym = arrow THEN { M2S.GetSym; M2G.GenDeRef [x] }

ELSE EXIT

ENDLOOP };

FormalParameters: PUBLIC PROC [proc: M2D.ProcPtr] =

{ isvar: BOOLEAN; par, par0: M2D.ObjPtr; typ0: M2D.StrPtr;

proc^.cell ← 0; proc^.adr ← 0;

IF (M2S.sym = ident) OR (M2S.sym = var) THEN

DO par0 ← M2T.LastObj []; isvar ← FALSE;

IF M2S.sym = var THEN { M2S.GetSym; isvar ← TRUE };

IF M2S.sym = ident THEN

{ par ← M2T.NewObj [M2S.id, Var]; M2S.KeepId; M2S.GetSym }

ELSE err [10];

IF M2S.sym = comma THEN M2S.GetSym

ELSE IF M2S.sym = ident THEN err [11]

ELSE IF M2S.sym = var THEN { err [11]; M2S.GetSym }

ELSE EXIT

ENDLOOP;

CheckSym [colon, 13];

typ0 ← FormalType []; par0 ← par0^.next;

WHILE par0 # NIL DO

var0: M2D.VarPtr ← NARROW [par0^.ext];

par0^.typ ← typ0; var0^.mod ← 0;

var0^.lev ← proc^.lev; var0^.varpar ← isvar;

IF proc^.cell >= 14 THEN { err [99]; proc^.cell ← 0 };

var0^.cell ← proc^.cell; proc^.cell ← proc^.cell + 1;

IF typ0^.form = Array THEN

{ array: M2D.ArrayPtr ← NARROW [typ0^.ext];

IF array^.dyn THEN

{ IF proc^.cell >= 14 THEN { err [99]; proc^.cell ← 0 };

proc^.cell ← proc^.cell + 1 } -- size

ELSE IF NOT isvar THEN proc^.adr ← proc^.adr + typ0^.size }

ELSE IF (typ0^.form = Record) AND NOT isvar THEN

proc^.adr ← proc^.adr + typ0^.size;

par0 ← par0^.next

ENDLOOP;

IF M2S.sym = semicolon THEN M2S.GetSym

ELSE IF M2S.sym = ident THEN err [12]

ELSE EXIT

ENDLOOP;

CheckSym [rparen, 15] };

ActualParameters: PUBLIC PROC [x: M2H.ItemPtr] =

{ apar: M2H.ItemPtr ← NEW [M2H.Item ← [contxt: x^.contxt]];

fpar: M2D.ParPtr ← M2G.PrepCall [x];

IF M2S.sym # rparen THEN

DO Expression [apar];

IF fpar # NIL THEN { M2G.GenParam [apar, fpar];

x^.expRegs ← M2D.UNION [x^.expRegs, apar^.expRegs]; fpar ← fpar^.next }

ELSE err [64];

IF M2S.sym = comma THEN M2S.GetSym

ELSE IF (M2S.sym >= lparen) AND (M2S.sym <= ident) THEN err [11]

ELSE EXIT

ENDLOOP;

IF fpar = NIL THEN M2G.GenCall [x] ELSE err [65] };

StandProcCall: PUBLIC PROC [p: M2H.ItemPtr] =

{ code: M2D.CodePtr ← NARROW [p^.obj^.ext];

m: CARDINAL ← code^.num; n: CARDINAL;

x: M2H.ItemPtr ← NEW [M2H.Item ← [contxt: p^.contxt]];

IF m = 1 THEN

{ M2G.GenTrap [10]; p^.typ ← M2D.notyp }

ELSE { CheckSym [lparen, 22]; n ← 0;

DO Expression [x]; M2F.GenStParam [p, x, m, n]; n ← n + 1;

IF M2S.sym = comma THEN M2S.GetSym

ELSE IF M2S.sym # ident THEN EXIT

ENDLOOP;

CheckSym [rparen, 15];

M2F.GenStFct [p, m, n] }};

Element: PROC [x: M2H.ItemPtr] =

{ e1: M2H.ItemPtr ← NEW [M2H.Item ← [contxt: x^.contxt]];

e2: M2H.ItemPtr ← NEW [M2H.Item ← [contxt: x^.contxt]];

Expression [e1];

IF M2S.sym = ellipsis THEN { M2S.GetSym;

IF e1^.mode = conMd THEN { Expression [e2];

IF e2^.mode # conMd THEN err [90] }

ELSE { M2H.Load [e1]; Expression [e2] };

M2G.GenSet [x, e1, e2] }

ELSE M2G.GenSingSet [x, e1] };

Sets: PROC [x: M2H.ItemPtr, styp: M2D.StrPtr] =

{ y: M2H.ItemPtr ← NEW [M2H.Item ← [contxt: x^.contxt]];

x^.typ ← styp; y^.typ ← styp;

IF M2S.sym # rbrace THEN { Element [x];

IF M2S.sym = comma THEN M2S.GetSym

ELSE

IF (M2S.sym >= lparen) AND (M2S.sym <= ident) THEN err [11]

ELSE EXIT;

M2H.Load [x];

Element [y]; M2H.Load [y];

M2H.GenOp [plus, x, y]

ENDLOOP }

ELSE { x^.mode ← conMd; x^.val.S ← ALL [FALSE] };

CheckSym [rbrace, 17] };

Factor: PROC [x: M2H.ItemPtr] =

{ obj: M2D.ObjPtr; xt: M2D.StrPtr;

IF M2S.sym < lparen THEN { err [31];

DO M2S.GetSym;

IF M2S.sym >= lparen THEN EXIT

ENDLOOP };

IF M2S.sym = ident THEN { obj ← qualident [];

IF M2S.sym = lbrace THEN { M2S.GetSym;

IF (obj # NIL) AND (obj^.class = Typ) AND (obj^.typ^.form = Set) THEN

Sets [x, obj^.typ]

ELSE { err [52]; Sets [x, M2D.bitstyp] }}

ELSE { Selector [x, obj];

IF x^.mode = codMd THEN

{ code: M2D.CodePtr ← NARROW [x^.obj^.ext];

IF code^.num > 0 THEN StandProcCall [x] }

ELSE IF M2S.sym = lparen THEN { M2S.GetSym;

IF x^.mode = typMd THEN -- type transfer function --

{ xt ← x^.typ; Expression [x]; M2H.Load [x];

IF xt^.size # x.typ^.size THEN err [81];

x^.typ ← xt }

ELSE ActualParameters [x];

CheckSym [rparen, 15] }}}

ELSE IF M2S.sym = number THEN

{ M2S.GetSym; x^.mode ← conMd;

SELECT M2S.numtyp FROM

cardint => { x^.typ ← M2D.cardtyp; x^.val.C ← M2S.intval };

longint => { x^.typ ← M2D.dbltyp; x^.val.D ← M2S.dblval };

char => { x^.typ ← M2D.chartyp; x^.val.C ← M2S.intval };

real => { x^.typ ← M2D.realtyp; x^.val.R ← M2S.realval };

longreal => { x^.typ ← M2D.realtyp; x^.val.R ← M2S.realval }

ENDCASE }

ELSE IF M2S.sym = string THEN

{ x^.typ ← M2D.stringtyp; x^.mode ← conMd;

[ x^.val.D0, x^.val.D1 ] ← M2I.AllocString [M2S.id];

M2S.GetSym }

ELSE IF M2S.sym = lparen THEN

{ M2S.GetSym; Expression [x]; CheckSym [rparen, 15] }

ELSE IF M2S.sym = lbrace THEN

{ M2S.GetSym; Sets [x, M2D.bitstyp] }

ELSE IF M2S.sym = not THEN

{ M2S.GetSym; Factor [x]; M2H.GenNot [x] }

ELSE { err [31]; x^.typ ← M2D.undftyp; x^.mode ← stkMd }};

Term: PROC [x: M2H.ItemPtr] =

{ y: M2H.ItemPtr ← NEW [M2H.Item ← [contxt: x^.contxt]];

mulop: M2S.Symbol;

Factor [x];

WHILE (M2S.sym >= times) AND (M2S.sym <= and) DO

mulop ← M2S.sym; M2S.GetSym;

IF x^.mode # conMd THEN

IF x^.typ^.form = Set THEN M2H.Load [x] ELSE M2H.LoadStk [x];

IF mulop = and THEN M2H.GenAnd [x];

Factor [y];

IF y^.mode # conMd THEN

IF y^.typ^.form = Set THEN M2H.Load [y] ELSE M2H.LoadStk [y];

M2H.GenOp [mulop, x, y]

ENDLOOP };

SimpleExpression: PROC [x: M2H.ItemPtr] =

{ y: M2H.ItemPtr ← NEW [M2H.Item ← [contxt: x^.contxt]];

addop: M2S.Symbol;

IF M2S.sym = minus THEN { M2S.GetSym; Term [x]; M2H.GenNeg [x] }

ELSE

{ IF M2S.sym = plus THEN M2S.GetSym;

Term [x] };

WHILE (M2S.sym >= plus) AND (M2S.sym <= or) DO

addop ← M2S.sym; M2S.GetSym;

IF addop = or THEN

{ IF x^.mode # conMd THEN M2H.LoadStk [x];

M2H.GenOr [x]; Term [y];

IF y^.mode # conMd THEN M2H.LoadStk [y] }

ELSE { M2H.Load [x]; Term [y]; M2H.Load [y] };

M2H.GenOp [addop, x, y]

ENDLOOP };

Expression: PUBLIC PROC [x: M2H.ItemPtr] =

{ y: M2H.ItemPtr ← NEW [M2H.Item ← [contxt: x^.contxt]];

relation: M2S.Symbol;

SimpleExpression [x];

IF (M2S.sym >= eql) AND (M2S.sym <= geq) THEN

{ relation ← M2S.sym; M2S.GetSym;

IF x^.mode # conMd THEN

IF x^.typ^.form = Set THEN M2H.Load [x] ELSE M2H.LoadStk [x];

SimpleExpression [y];

IF y^.mode # conMd THEN M2H.Load [y];

M2H.GenOp [relation, x, y] }

ELSE IF M2S.sym = in THEN { M2S.GetSym;

IF x^.mode # conMd THEN M2H.LoadStk [x];

SimpleExpression [y]; M2H.Load [y];

M2H.GenIn [x, y] }};

ConstExpression: PUBLIC PROC [x: M2H.ItemPtr] =

{ x^.contxt ← dummyContxt;

Expression [x];

IF x^.mode # conMd THEN

{ err [44]; x^.mode ← conMd; x^.val.C ← 1 }};

END.