Copyright (c) 2000 California Institute of Technology
All rights reserved. See the file COPYRIGHT for a full description.
$Id: Sym.m3.html,v 1.3 2010-04-29 17:18:53 wagner Exp $
MODULE Sym;
IMPORT Prec;
IMPORT Text;
IMPORT TextPrecTbl;
IMPORT TextBooleanTbl;
IMPORT TextIntTbl;
IMPORT Fmt;
IMPORT CharCodes;
IMPORT Term;
REVEAL
T = BRANDED REF RECORD
name: TEXT; (* NIL means CharSym *)
code: INTEGER;
start, const: BOOLEAN;
END;
PROCEDURE AllocCode(a: T; into: TextIntTbl.T; VAR lastCode: INTEGER) =
BEGIN
IF a.name # NIL THEN
IF NOT into.get(a.name, a.code) THEN
IF Text.Equal(a.name, "EOF") THEN
a.code := 0;
ELSE
INC(lastCode);
a.code := lastCode;
EVAL into.put(a.name, a.code);
END;
END;
END;
END AllocCode;
PROCEDURE SetAttrs(a: T; start: TextBooleanTbl.T;
const: TextIntTbl.T) =
VAR
dummy: INTEGER;
BEGIN
IF a.name = NIL THEN
a.const := TRUE;
ELSE
EVAL start.get(a.name, a.start);
a.const := const.get(a.name, dummy);
END;
END SetAttrs;
PROCEDURE GetName(a: T): TEXT =
BEGIN
IF a.name = NIL THEN
RETURN "@" & Text.FromChar(VAL(a.code, CHAR));
ELSE
RETURN a.name;
END;
END GetName;
PROCEDURE Format(a: T): TEXT =
BEGIN
IF a.name # NIL THEN
RETURN a.name (* & "=" & Fmt.Int(a.code) *);
ELSIF a.code = 0 THEN
RETURN "EOF";
ELSE
RETURN CharCodes.QC(VAL(a.code, CHAR)) (* & "=" & Fmt.Int(a.code) *);
END;
END Format;
PROCEDURE GetCode(a: T): INTEGER =
BEGIN RETURN a.code; END GetCode;
PROCEDURE GetPrec(a: T; prec: TextPrecTbl.T): Prec.T =
VAR
key := a.name;
val: Prec.T := NIL;
BEGIN
IF key = NIL THEN
key := "@" & Text.FromChar(VAL(a.code, CHAR));
END;
IF prec.get(key, val) THEN
Term.WrLn(Found prec:
& key & Fmt.Int(val.val));
ELSE
Term.WrLn(Not finding prec:
& key);
END;
RETURN val;
END GetPrec;
PROCEDURE IsStart(a: T): BOOLEAN =
BEGIN RETURN a.start; END IsStart;
PROCEDURE IsConst(a: T): BOOLEAN =
BEGIN RETURN a.const; END IsConst;
PROCEDURE FromText(t: TEXT): T =
BEGIN
RETURN NEW(T, name := t, code := -1, start := FALSE);
END FromText;
PROCEDURE FromChar(c: CHAR): T =
BEGIN
RETURN NEW(T, name := NIL, code := ORD(c), start := FALSE);
END FromChar;
PROCEDURE Equal(a,b: T): BOOLEAN =
BEGIN RETURN a.code = b.code; END Equal;
BEGIN
END Sym.