// Integer arithmetic interpreter value (avalue)
// declaration.
//
// File:        iavalue.h
// Author:      course
// Version:     2
//
// This file declares the arithmetic interpreter value
// type, or avalue.
//
// This version of the file declares avalues to be
// simple integers that are added, subtracted, etc. as
// per usual arithmetic.
//
// Other versions of this file and its companion
// avalue.cc file may be written without changing the
// rest of the interpreter program.

#ifndef _AVALUE_H_
#define _AVALUE_H_

#include "basic.h"     // Coursewide basic declarations.

// Lexeme_class are declared later, in lexeme.h, but
// used here.  A lexeme is a pointer to a lexeme_class:
//
class lexeme_class;
typedef lexeme_class * lexeme;



// Definition of avalue type.  With this particular
// definition, the operators <<, >>, +, -, *, / come
// for free.
//
typedef long avalue;



// `Zero' avalue, which becomes value of empty program.
//
extern avalue zero_avalue;



// Functions involving avalues.

// Evaluate a lexeme to produce a value.  Lexeme must be
// number or symbol.
//
avalue evaluate (lexeme l);

// Assign to a lexeme.  Returns the value assigned.
//
avalue assign (lexeme l, avalue v);

// Initialize avalues.
//
void init_avalues (void);

#endif  // _AVALUE_H_