/*
 * expr.h
 *
 * Copyright (C) 1989, 1991, Craig E. Kolb, Rod G. Bogart
 * All rights reserved.
 *
 * This software may be freely copied, modified, and redistributed
 * provided that this copyright notice is preserved on all copies.
 *
 * You may not distribute this software, in whole or in part, as part of
 * any commercial product without the express consent of the authors.
 * 
 * There is no warranty or other guarantee of fitness of this software
 * for any purpose.  It is provided solely "as is".
 *
 * $Id: expr.h,v 4.0 91/07/17 14:30:47 kolb Exp Locker: kolb $
 *
 * $Log:	expr.h,v $
 * Revision 4.0  91/07/17  14:30:47  kolb
 * Initial version.
 * 
 */
#ifndef EXPR_H
#define EXPR_H

#define FLOAT_EXPR		0
#define BUILTIN_EXPR		1

typedef struct Expr {
	short	type,			/* Expr type (float/builtin/time) */
		timevary,		/* does the expr vary over time? */
		symtab,			/* is the expr in the symtab? */
		nparams;		/* # of params, if builtin */
	Float	value,			/* float val/last eval if timeexpr */
		timenow,		/* time of last evaluation */
		(*function)();
	struct Expr **params;		/* parameters, if a builtin */
} Expr;

typedef struct ExprAssoc {
	Float *lhs;			/* left-hand side */
	Expr *expr;			/* right-hand side */
	struct ExprAssoc *next;		/* Next in list */
} ExprAssoc;
	
extern Float	ExprEval();

extern Expr	*ExprResolve1(), *ExprResolve2(), *ExprResolve3(),
		*ExprResolve4(), *ExprResolve5(), *ExprFloatCreate();
extern Expr	*TimeExpr, *FrameExpr, *ExprReuseFloatCreate();

extern ExprAssoc *AssocCreate();

#endif /* EXPR_H */