Function xo_xml_leader_len

tools/libxo/libxo/libxo.c:564–572

* For XML, the first character of a tag cannot be numeric, but people * will likely not notice. So we people-proof them by forcing a leading * underscore if they use invalid tags. Note that this doesn't cover * all broken tags, just this fairly specific case. */

 * all broken tags, just this fairly specific case.
 */
static const char *
xo_xml_leader_len (xo_handle_t *xop, const char *name, xo_ssize_t nlen)
{
    if (name == NULL || isalpha(name[0]) || name[0] == '_')
        return "";

    xo_failure(xop, "invalid XML tag name: '%.*s'", nlen, name);
    return "_";
}

static const char *
xo_xml_leader (xo_handle_t *xop, const char *name)