Method flwor

basex-core/src/main/java/org/basex/query/QueryParser.java:1153–1243

Parses the "FLWORExpr" rule. Parses the "WhereClause" rule. Parses the "WhileClause" rule. Parses the "OrderByClause" rule. Parses the "OrderSpecList" rule. Parses the "GroupByClause" rule. @return query expression or null @throws QueryException query exception

()

   * @throws QueryException query exception
   */
  private Expr flwor() throws QueryException {
    final int s = localVars.openScope();
    final LinkedList<Clause> clauses = initialClause(null);
    if(clauses == null) return null;

    final TokenObjectMap<Var> curr = new TokenObjectMap<>();
    for(final Clause fl : clauses)
      for(final Var var : fl.vars()) curr.put(var.name.unique(), var);

    int size;
    do {
      do {
        size = clauses.size();
        initialClause(clauses);
        for(final Clause clause : clauses) {
          for(final Var var : clause.vars()) curr.put(var.name.unique(), var);
        }
      } while(size < clauses.size());

      if(wsConsumeWs(WHERE)) {
        alterPos = pos;
        clauses.add(new Where(check(single(), NOWHERE), info()));
      }

      if(wsConsumeWs(WHILE)) {
        alterPos = pos;
        clauses.add(new While(check(single(), NOWHILE), info()));
      }

      if(wsConsumeWs(GROUP)) {
        wsCheck(BY);
        skipWs();
        alterPos = pos;
        final GroupSpec[] specs = groupSpecs(clauses);

        // find all non-grouping variables that aren't shadowed
        final ArrayList<VarRef> ng = new ArrayList<>();
        for(final GroupSpec spec : specs) curr.put(spec.var.name.unique(), spec.var);
        VARS:
        for(final Var var : curr.values()) {
          for(final GroupSpec spec : specs) {
            if(spec.var == var) continue VARS;
          }
          ng.add(new VarRef(specs[0].info(), var));
        }

        // add new copies for all non-grouping variables
        final int ns = ng.size();
        final Var[] ngrp = new Var[ns];
        for(int i = ns; --i >= 0;) {
          final VarRef ref = ng.get(i);
          // if one groups variables such as $x as xs:integer, then the resulting
          // sequence isn't compatible with the type and can't be assigned
          final Var nv = localVars.add(new Var(ref.var.name, null, qc, ref.var.info));
          ngrp[i] = nv;
          curr.put(nv.name.unique(), nv);
        }
        clauses.add(new GroupBy(specs, ng.toArray(VarRef[]::new), ngrp, specs[0].info()));