Syntax10.Scn.Fnt
Syntax10i.Scn.Fnt
StampElems
Alloc
7 Mar 95
Syntax10b.Scn.Fnt
MODULE ExprBessel; (* ww 
	IMPORT
		Files, Fonts, Expressions, ExprViews, ExprStd;
	TYPE
		BesselFunction* = POINTER TO RECORD(Expressions.ExpressionDesc)
			name-: CHAR;
			index-, argument-: Expressions.Expression
		END;
	PROCEDURE Min(x, y: LONGINT): LONGINT;
	BEGIN IF x < y THEN RETURN x ELSE RETURN y END
	END Min;
	PROCEDURE Max(x, y: LONGINT): LONGINT;
	BEGIN IF x < y THEN RETURN y ELSE RETURN x END
	END Max;
	PROCEDURE Draw(b: ExprViews.Box; p: ExprViews.Port; x, y: LONGINT; col: INTEGER);
	BEGIN p.DrawChar(b.exp(BesselFunction).name, x, y, b.fnt, col);
		ExprViews.DrawDesc(b, p, x, y, col)
	END Draw;
	PROCEDURE Box(e: BesselFunction; port: ExprViews.Port; depth: LONGINT; fnt: Fonts.Font): ExprViews.Box;
		VAR w, bot, top, lH, eH: LONGINT; b, ind, arg: ExprViews.Box; fnt1: Fonts.Font;
	BEGIN
		IF depth > 0 THEN NEW(b);
			fnt1 := port.SmallerFont(fnt);
			ind := ExprViews.ExprBox(e.index, b, 0, port, depth -1, fnt1);
			arg := ExprViews.ExprBox(e.argument, b, 1, port, depth -1, fnt);
			arg := ExprViews.BracketBox("(", arg, port, fnt); arg.y := 0;
			IF fnt1 # fnt THEN top := arg.top; bot := arg.bot;
				lH := ind.top - ind.bot; eH := top - bot;
				IF lH < eH THEN ind.y := bot - ind.bot - lH DIV 2 ELSE ind.y := bot + eH DIV 2 - ind.top END;
				bot := ind.y + ind.bot
			ELSE ind := ExprViews.BracketBox("[", ind, port, fnt);
				ind.y := 0;
				bot := Min(ind.bot, arg.bot); top := Max(ind.top, arg.top)
			END;
			w := port.CharWidth(e.name, fnt);
			ind.x := w; w := w + ind.w; ind.next := arg;
			arg.x := w; w := w + arg.w;
			b.desc := ind; b.w := w; b.bot := bot; b.top := top; b.fnt := fnt; b.draw := Draw
		ELSE b := ExprViews.EllipsisBox(NIL, port, fnt)
		END;
		RETURN b
	END Box;
	PROCEDURE Init(e: BesselFunction);
		VAR r: Expressions.Rider;
	BEGIN
		ASSERT((Expressions.LengthOf(e.successors) = 2) &
			((e.name = "I") OR (e.name = "J") OR (e.name = "K") OR (e.name = "Y"))
		Expressions.OpenRider(r, e.successors); e.index := r.exp; Expressions.Forward(r); e.argument := r.exp
	END Init;
	PROCEDURE Handler(e: Expressions.Expression; VAR m: Expressions.Message);
		VAR self, c: BesselFunction; s: ARRAY 8 OF CHAR;
	BEGIN self := e(BesselFunction);
		WITH m: Expressions.IdentifyMsg DO m.mod := "ExprBessel"; m.proc := "AllocBesselFunction"
		| m: Expressions.FileMsg DO
			IF m.store THEN Files.Write(m.r, self.name)
			ELSE Files.Read(m.r, self.name); Init(self)
			END
		| m: Expressions.CloneMsg DO NEW(c);
			Expressions.Init(c, self.handle, self.binding, ORD(self.name), m.successors);
			c.name := self.name; Init(c);
			m.clone := c
		| m: Expressions.TestMsg DO
			m.equal := (m.with IS BesselFunction) & (m.with(BesselFunction).name = self.name)
				& Expressions.EqualLists(m.with.successors, self.successors)
		| m: ExprViews.GetBoxMsg DO m.box := Box(self, m.port, m.depth, m.fnt)
		| m: ExprStd.ExpansionMsg DO
			s := "Bessel "; s[6] := self.name;
			m.exp := ExprStd.NewFunction(s, self.successors)
		ELSE (* ignore *)
		END
	END Handler;
	PROCEDURE AllocBesselFunction*;
		VAR e: BesselFunction;
	BEGIN NEW(e); Expressions.Alloc(e, Handler)
	END AllocBesselFunction;
	PROCEDURE NewBesselFunction*(name: CHAR; index, argument: Expressions.Expression): BesselFunction;
		VAR e: BesselFunction; r: Expressions.Rider;
	BEGIN ASSERT((name = "I") OR (name = "J") OR (name = "K") OR (name = "Y"));
		NEW(e);
		Expressions.OpenRider(r, Expressions.emptyList);
		Expressions.Insert(r, index, 0); Expressions.Insert(r, argument, 0);
		Expressions.Init(e, Handler, Expressions.AtomBind, ORD(name), Expressions.ThisList(r));
		e.name := name; e.index := index; e.argument := argument;
		RETURN e
	END NewBesselFunction;
	PROCEDURE Substitute*(VAR exp: Expressions.Expression);
		VAR e: BesselFunction; name: ExprStd.Name;
	BEGIN
		IF (exp IS ExprStd.Function) & (Expressions.LengthOf(exp.successors) = 2) THEN
			name := exp(ExprStd.Function).name;
			IF (name = "BesselI") OR (name = "BesselJ") OR (name = "BesselK") OR (name = "BesselY") THEN
				NEW(e); e.name := name[6];
				Expressions.Init(e, Handler, Expressions.AtomBind, ORD(e.name), exp.successors);
				Init(e);
				exp := e
			END
		END
	END Substitute;
	PROCEDURE Install*;
	BEGIN ExprStd.Register(Substitute)
	END Install;
	PROCEDURE Remove*;
	BEGIN ExprStd.Remove(Substitute)
	END Remove;
END ExprBessel.