#ifndef VALUE_H
#define VALUE_H

#include "lexer.h"
#include "env.h"

typedef struct value * value_t;
#define VALUE_EMPTY NULL

typedef value_t (*builtin_proc_t)(value_t *args);

#define VALUE_TYPES(X)         \
    X(VALUE_NIL)               \
    X(VALUE_ATOM)              \
    X(VALUE_STR)               \
    X(VALUE_INT)               \
    X(VALUE_CONS)              \
    X(VALUE_PROC)              \
    X(VALUE_PROC_BUILTIN)      

#define TO_ENUM(type) type,
#define TO_STRING(type) #type,

extern const char * const value_type_string[];
        
struct value {
    enum value_type {
        VALUE_TYPES(TO_ENUM)
    } type;

    union value_union {
        char *atom;
        char *str;
        int   num;

        struct cons {
            value_t left;
            value_t right;
        } cons;

        struct proc {
            size_t argc;
            value_t *arg_keys;
            env_t parent_env;
            
            size_t body_len;
            struct token *body;
        } proc;

        struct proc_builtin {
            size_t argc;
            builtin_proc_t proc;
        } proc_builtin;
    } value;

    size_t refs;
};

value_t value_create(enum value_type type, void * value);
void value_destroy(value_t value);

value_t value_from_token(struct token *token);
value_t value_copy(value_t value);
int value_string(value_t value, size_t buf_sz, char *buf);

#endif