aura_buffer_eof
int aura_buffer_eof(struct aura_buffer *);
while (isdigit(aura_buffer_peek_char(e)) && !aura_buffer_eof(e)) {
while (len > 0 && !aura_buffer_eof(e)) {
while (isdigit(aura_buffer_peek_char(e)) && !aura_buffer_eof(e)) {