Function power

external_libraries/tinyexpr/tinyexpr/tinyexpr.c:448–471

static te_expr *power(state *s) {
    /* <power>     =    {("-" | "+")} <base> */
    int sign = 1;
    while (s->type == TOK_INFIX && (s->function == add || s->function == sub)) {
        if (s->function == sub) sign = -sign;
        next_token(s);
    }

    te_expr *ret;

    if (sign == 1) {
        ret = base(s);
    } else {
        te_expr *b = base(s);
        CHECK_NULL(b);

        ret = NEW_EXPR(TE_FUNCTION1 | TE_FLAG_PURE, b);
        CHECK_NULL(ret, te_free(b));

        ret->function = negate;
    }

    return ret;
}

#ifdef TE_POW_FROM_RIGHT
static te_expr *factor(state *s) {