Function factor

extern/tinyexpr/tinyexpr.c:416–453

#ifdef TE_POW_FROM_RIGHT
static te_expr *factor(state *s) {
    /* <factor>    =    <power> {"^" <power>} */
    te_expr *ret = power(s);

    int neg = 0;
    te_expr *insertion = 0;

    if (ret->type == (TE_FUNCTION1 | TE_FLAG_PURE) && ret->function == negate) {
        te_expr *se = ret->parameters[0];
        free(ret);
        ret = se;
        neg = 1;
    }

    while (s->type == TOK_INFIX && (s->function == pow)) {
        te_fun2 t = s->function;
        next_token(s);

        if (insertion) {
            /* Make exponentiation go right-to-left. */
            te_expr *insert = NEW_EXPR(TE_FUNCTION2 | TE_FLAG_PURE, insertion->parameters[1], power(s));
            insert->function = t;
            insertion->parameters[1] = insert;
            insertion = insert;
        } else {
            ret = NEW_EXPR(TE_FUNCTION2 | TE_FLAG_PURE, ret, power(s));
            ret->function = t;
            insertion = ret;
        }
    }

    if (neg) {
        ret = NEW_EXPR(TE_FUNCTION1 | TE_FLAG_PURE, ret);
        ret->function = negate;
    }

    return ret;
}
#else
static te_expr *factor(state *s) {
    /* <factor>    =    <power> {"^" <power>} */