/*ident	"@(#)Symbol:incl/Symbol.h	3.1" */
/******************************************************************************
*
* C++ Standard Components, Release 3.0.
*
* Copyright (c) 1991, 1992 AT&T and Unix System Laboratories, Inc.
* Copyright (c) 1988, 1989, 1990 AT&T.  All Rights Reserved.
*
* THIS IS UNPUBLISHED PROPRIETARY SOURCE CODE OF AT&T and Unix System
* Laboratories, Inc.  The copyright notice above does not evidence
* any actual or intended publication of such source code.
*
******************************************************************************/

#ifndef SYMBOL_H__
#define SYMBOL_H__

#include <String.h>
#include <Set.h>

class Symbol {

public:
    inline Symbol();
    Symbol(const String& s);
    Symbol(const char* p);
    Symbol(const Symbol& s) : sp(s.sp) {}

    inline Symbol& operator=(const Symbol& b);

    int operator==(const Symbol& b) const { return sp == b.sp; }
    int operator!=(const Symbol& b) const { return sp != b.sp; }
    int operator<(const Symbol& b) const { return sp < b.sp; }
    int operator<=(const Symbol& b) const { return sp <= b.sp; }
    int operator>(const Symbol& b) const { return sp > b.sp; }
    int operator>=(const Symbol& b) const { return sp >= b.sp; }

    String the_string() const { return *sp; }
    unsigned long hashval() const { return (unsigned long)sp; }
    static void cleanup() { 	// for purify users: call this at end of
			// application program to clean up potential memory 
			// leak messages from purify
	if (table_ptr!=0) delete table_ptr; table_ptr=0; nil_=0; }

private:
    static void initialize() { if (nil_ == 0) doinitialize(); }
    static void doinitialize();
    static Set<String>* table_ptr;
    static const String* nil_;
    static const String* nil() { initialize(); return nil_; }
    const String* sp;
};

class istream;
class ostream;
istream& operator>>(istream& is, Symbol& s);
ostream& operator<<(ostream& os, const Symbol& s);

Symbol::Symbol() {
    sp = nil();
}

Symbol& Symbol::operator=(const Symbol& b) {
    sp = b.sp;
    return *this;
}

#ifdef __edg_att_40
#pragma can_instantiate Set<String>
#endif

#endif