_igw2str(s)
{
        local g, j, outstr, len;

        if (argc < 2)
        {
                nostr = "{}";
        }

        g = s;
        j = 1;
        outstr = "{";

        while (strlen(g) > 0)
        {
                h = strfind(sprintf("-%d", j), g);
                if (strlen(h) > 0)
                {
                        /* have term */
                        outstr = strcat(outstr, "1,");
                        g = strextract(h, 3, -1);
                }
                else
                {
                        outstr = strcat(outstr, "0,");
                }
                j++;
        }
        len = strlen(outstr);
        outstr[len] = "}";
        if (outstr == "}" || outstr == "{}" || outstr == "{0,0,1,1,1}")
        {
                outstr = "";
        }
        return(outstr);
}