#ifndef EVALEXPR_H
#define EVALEXPR_H

#include <stddef.h>

#include "fifo.h"
#include "stack.h"
#include "stack_struct.h"

enum token_type
{
    NUMBER = 0,
    SUB = 1,
    ADD = 1,
    MOD = 2,
    DIV = 2,
    MUL = 2,
    EXP = 3,
    UN_PLUS = 4,
    UN_MINUS = 4,
    PAR_LEFT = 5,
    PAR_RIGHT = 5,
    WRONG_TOKEN = -1,
};

struct token
{
    enum token_type type;
    int value;
};

// evalrpn
int parse_number(const char *expr, size_t *offset);
int get_operands(struct stack **s, int *op1, int *op2);
int my_pow(int a, int b);
int evalrpn(const char *expr, int *retval);

// shunting yard
int opcmp(struct token *op1, struct token *op2);
enum token_type get_type(char op);
int shunting_yard(const char *expr, char **rpn);

#endif /* ! EVALEXPR_H */