File: Field.m3 Last modified on Wed Mar 1 08:43:31 PST 1995 by kalsow modified on Fri Apr 20 06:47:07 1990 by muller
MODULE; IMPORT M3, CG, Value, ValueRep, Type, Expr, Error; IMPORT AssignStmt, M3Buf; TYPE T = Value.T BRANDED OBJECT index : INTEGER; offset : INTEGER; tipe : Type.T; dfault : Expr.T; OVERRIDES typeCheck := TypeCheck; set_globals := SetGlobals; load := ValueRep.NoLoader; declare := ValueRep.Never; const_init := ValueRep.NoInit; need_init := ValueRep.Never; lang_init := Compile; user_init := ValueRep.NoInit; toExpr := ValueRep.NoExpr; toType := ValueRep.NoType; typeOf := TypeOf; base := ValueRep.Self; add_fp_tag := AddFPTag; fp_type := TypeOf; END; PROCEDURE Field New (READONLY info: Info): Value.T = VAR t := NEW (T); BEGIN ValueRep.Init (t, info.name, Value.Class.Field); t.index := info.index; t.offset := info.offset; t.tipe := info.type; t.dfault := info.dfault; RETURN t; END New; PROCEDUREIs (v: Value.T): BOOLEAN = BEGIN TYPECASE v OF | NULL => RETURN FALSE; | T => RETURN TRUE; ELSE RETURN FALSE; END; END Is; PROCEDURESplit (field: Value.T; VAR info: Info) = VAR t: T := field; BEGIN info.name := t.name; info.index := t.index; info.offset := t.offset; info.type := t.tipe; info.dfault := t.dfault; END Split; PROCEDURESetOffset (field: Value.T; newOffset: INTEGER) = VAR t: T := field; BEGIN t.offset := newOffset; END SetOffset; PROCEDUREEmitDeclaration (field: Value.T) = VAR t: T := field; info : Type.Info; BEGIN EVAL Type.CheckInfo (t.tipe, info); Type.Compile (t.tipe); CG.Declare_field (t.name, t.offset, info.size, Type.GlobalUID (t.tipe)); END EmitDeclaration; PROCEDUREIsEqualList (a, b: Value.T; x: Type.Assumption; types: BOOLEAN): BOOLEAN = BEGIN WHILE (a # NIL) AND (b # NIL) DO IF NOT IsEqual (a, b, x, types) THEN RETURN FALSE END; a := a.next; b := b.next; END; RETURN (a = NIL) AND (b = NIL); END IsEqualList; PROCEDUREIsEqual (va, vb: Value.T; x: Type.Assumption; types: BOOLEAN): BOOLEAN = VAR a: T := va; b: T := vb; BEGIN IF (a = NIL) OR (b = NIL) OR (a.name # b.name) OR (a.index # b.index) THEN RETURN FALSE; END; IF NOT types THEN RETURN TRUE; END; (* now, we'll do the harder type-based checks... *) RETURN Type.IsEqual (TypeOf (a), TypeOf (b), x) AND Expr.IsEqual (Expr.ConstValue (a.dfault), Expr.ConstValue (b.dfault), x); END IsEqual; PROCEDURETypeOf (t: T): Type.T = BEGIN IF (t.tipe = NIL) THEN t.tipe := Expr.TypeOf (t.dfault) END; RETURN t.tipe; END TypeOf; PROCEDURETypeCheck (t: T; VAR cs: Value.CheckState) = VAR info: Type.Info; BEGIN t.tipe := Type.CheckInfo (TypeOf (t), info); IF (info.isEmpty) THEN Error.ID (t.name, "empty field type"); END; IF (info.class = Type.Class.OpenArray) THEN Error.ID (t.name, "fields may not be open arrays"); END; t.checked := TRUE; IF (t.dfault # NIL) THEN (* check for assignability!! *) AssignStmt.Check (t.tipe, t.dfault, cs); Expr.TypeCheck (t.dfault, cs); IF (Expr.ConstValue (t.dfault) = NIL) THEN Error.ID (t.name, "default is not a constant"); END; (* NOTE: we don't save the constant-folded version of the default, otherwise we'd loose references to large named constants. *) END; END TypeCheck; PROCEDURECompile (t: T) = BEGIN Type.Compile (t.tipe); END Compile; PROCEDURESetGlobals (<*UNUSED*> t: T) = BEGIN (* Type.SetGlobals (t.tipe); *) (* IF (t.dfault # NIL) THEN Type.SetGlobals (Expr.TypeOf (t.dfault)) END; *) END SetGlobals; PROCEDUREAddFPTag (t: T; VAR x: M3.FPInfo): CARDINAL = BEGIN ValueRep.FPStart (t, x, "FIELD ", 0, global := FALSE); IF (t.dfault # NIL) THEN M3Buf.PutText (x.buf, " := "); Expr.GenFPLiteral (t.dfault, x.buf); END; RETURN 1; END AddFPTag; BEGIN END Field.