Method merge

basex-core/src/main/java/org/basex/query/expr/Mapping.java:157–196

Merges adjacent operands. @param cc compilation context @return resulting expression or null @throws QueryException query exception

(final CompileContext cc)

   * @throws QueryException query exception
   */
  final Expr[] merge(final CompileContext cc) throws QueryException {
    final int el = exprs.length;
    final ExprList list = new ExprList(el).add(exprs[0]);

    boolean pushed = false;
    try {
      final boolean items = items();
      for(int e = 1; e < el; e++) {
        final Expr merged = merge(list.peek(), exprs[e], cc);
        if(merged != null) {
          list.set(list.size() - 1, merged);
        } else {
          list.add(exprs[e]);
        }
        if(list.size() > 1) {
          final Expr expr = list.get(list.size() - 2);
          if(pushed) {
            cc.updateFocus(expr, items);
          } else {
            cc.pushFocus(expr, items);
            pushed = true;
          }
        }
      }
    } finally {
      if(pushed) cc.removeFocus();
    }

    // remove context value references (ignore first expression)
    // (1 to 10) ! . → (1 to 10)
    for(int n = list.size() - 1; n > 0; n--) {
      if(list.get(n) instanceof ContextValue) list.remove(n);
    }

    final int ls = list.size();
    if(ls == el) return null;

    cc.info(OPTSIMPLE_X_X, (Supplier<?>) this::description, this);
    return list.finish();
  }

  /**
   * Merges adjacent operands.