/**
* Checks the specified template and adds a variable.
*
* @param tmp template string
* @param type allowed type
* @param declared variable declaration flags
* @return resulting variable
* @throws QueryException query exception
*/
private QNm checkVariable(final String tmp, final Type type, final boolean[] declared)
throws QueryException {
final Var[] args = function.args;
final Matcher m = TEMPLATE.matcher(tmp);
if (!m.find()) error(INV_TEMPLATE, tmp);
final byte[] vn = token(m.group(1));
if (!XMLToken.isQName(vn)) error(INV_VARNAME, vn);
final QNm qnm = new QNm(vn, context);
int r = -1;
while (++r < args.length && !args[r].name.eq(qnm)) ;
if (r == args.length) error(UNKNOWN_VAR, vn);
if (declared[r]) error(VAR_ASSIGNED, vn);
final SeqType st = args[r].declaredType();
if (args[r].checksType() && !st.type.instanceOf(type)) error(INV_VARTYPE, vn, type);
declared[r] = true;
return qnm;
}
