expression.h

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#ifndef EXPRESSION_H_INCLUDED
#define EXPRESSION_H_INCLUDED

#include <stddef.h> /* size_t */

#include "types.h"
#include "symbolic.h"
#include "expression_lite.h" /* expression_t only exists in expression_lite.h */

/*---------------------------------------------*
 *     Misc. String Buffer Definitions         *
 *---------------------------------------------*/
#define EXP_BUF_SIZE 256
typedef char exp_buf[EXP_BUF_SIZE];


/*---------------------------------------------*
 *     expression tree structure               *
 *---------------------------------------------*/
/* The tree operation element for the expression structure */
struct expression_data_tree {
    char op; // '+', '-', '*', or '/'
    expression_t left;  
    expression_t right; 
};


/*---------------------------------------------*
 *     expression components                   *
 *---------------------------------------------*/

enum expression_type {
//    EXP_UNDEF, ///< \note Might remove
    EXP_VALUE,    
    EXP_TREE,     
    EXP_SYMBOLIC  
};

union expression_data {
    value_t                     val;   
    struct expression_data_tree tree;  
    sym_t                       sym;   
};

/*---------------------------------------------*
 *     expression structure                    *
 *---------------------------------------------*/
struct expression {
    enum expression_type  type; 
    union expression_data data; 
};

/*---------------------------------------------*
 *     expression_t allocation functions       *
 *---------------------------------------------*/

expression_t
expression_new (void);

expression_t
expression_new_value (value_t val);

expression_t
expression_new_tree (char op,
                     expression_t left,
                     expression_t right);

expression_t
expression_new_sym (sym_t sym);

void
expression_free (expression_t exp);


/*---------------------------------------------*
 *     expression_t manipulation functions     *
 *---------------------------------------------*/

value_t
expression_evaluate (expression_t exp);

void
expression_to_string (char *dst_str,
                      expression_t src_exp);

expression_t
string_to_expression (size_t str_len,
                      char const *str);

#endif // EXPRESSION_H_INCLUDED

/* vim: set ts=4 sw=4 expandtab: */