static char* lispy_version = "Lispy version 0.0.0.0.5";


/* Parser language defintion */
static char* parser =
"                                                   \
    number   : /-?[0-9]+([.][0-9]*|[0-9]*)/ ;       \
    symbol : '+' | '-' | '*' | '/' | '%' | '^' |    \
    \"min\" | \"max\" ;                             \
    sexpr    : '(' <expr>* ')' ;                    \
    expr     : <number> | <symbol> | <sexpr> ;      \
    lispy    : /^/ <expr>* /$/ ;                    \
";


/* Declare new lval struct */
typedef struct lval {
    int type;
    long num;
    double dec;
    /* Error & symbol types have some string data */
    char* err;
    char* sym;
    /* Counter & pointer to a list of lval */
    size_t count;
    struct lval** cell;
} lval;


/* Create enumeration of possible lval types */
enum {LVAL_NUM, LVAL_DEC, LVAL_SYM, LVAL_SEXPR, LVAL_ERR};

/* lval constructor functions */
lval* lval_num(long x);
lval* lval_dec(double x);
lval* lval_err(char* m);
lval* lval_sym(char* s);
lval* lval_sexpr(void);

/* lval destructor function */
void lval_del(lval* v);

/* lval manipulating functions */
lval* lval_add(lval* v, lval* x);
lval* lval_pop(lval* v, size_t i);
lval* lval_take(lval* v, size_t i);

lval* lval_read_num(mpc_ast_t* t);
lval* lval_read(mpc_ast_t* t);
lval* lval_eval_sexpr(lval* v);
lval* lval_eval(lval* v);

void lval_expr_print(lval* v, char open, char close);
void lval_print(lval* v);
void lval_println(lval* v);

long min(long x, long y);
long max(long x, long y);

lval* builtin_op(lval* a, char* op);