int _next_error (~string)
{
	returns (search_fwd ("<[~ \t\n]+.[~ \t\n]+(\\c[0-9]+)", 1, 0));
}

int _prev_error (~string)
{
	returns (search_back ("<[~ \t\n]+.[~ \t\n]+(\\c[0-9]+)", 1, 0));
}