Method item

basex-core/src/main/java/org/basex/query/func/Functions.java:149–202

Creates a function item expression. @param qnm function name @param arity number of arguments @param runtime true if this method is called at runtime @param info input info (can be null) @param qc query context @return literal if found, null otherwise @throws QueryException q

(final QNm qnm, final int arity, final boolean runtime,
      final InputInfo info, final QueryContext qc)

   * @throws QueryException query exception
   */
  public static Expr item(final QNm qnm, final int arity, final boolean runtime,
      final InputInfo info, final QueryContext qc) throws QueryException {

    final FuncBuilder fb = new FuncBuilder(info, arity, runtime);
    final QNm name = funcName(qnm, arity, info, qc);

    // constructor function
    if(eq(name.uri(), XS_URI)) {
      if(arity > 0) fb.add(CAST_PARAM[0], Types.ANY_ATOMIC_TYPE_ZO, qc);
      final Cast expr = constructorCall(name, fb);
      final FuncType ft = FuncType.get(fb.anns, expr.castType(), fb.params);
      return item(expr, fb, ft, name, false, arity == 0);
    }

    // built-in function
    final FuncDefinition fd = builtIn(name);
    if(fd != null) {
      final IntList arts = checkArity(arity, fd.minMax[0], fd.minMax[1]);
      if(arts != null) throw wrongArity(arity, arts, true, info, fd);

      final FuncType ft = fd.type(arity, fb.anns);
      final QNm[] names = fd.paramNames(arity);
      for(int a = 0; a < arity; a++) fb.add(names[a], ft.argTypes[a], qc);
      final StandardFunc sf = fd.get(info, fb.args());
      final boolean updating = sf.hasUPD();
      if(updating) {
        fb.anns = fb.anns.attach(new Ann(info, Annotation.UPDATING, Empty.VALUE));
        qc.updating();
      }
      return item(sf, fb, ft, name, updating, sf.has(Flag.CTX));
    }

    // user-defined function
    final StaticFunc sf = qc.functions.get(info.sc(), name, arity, runtime);
    if(sf != null) {
      final Expr func = item(sf, fb, qc);
      if(sf.updating) qc.updating();
      return func;
    }

    for(int a = 0; a < arity; a++) fb.add(new QNm(ARG + (a + 1), ""), null, qc);

    // Java function
    final JavaCall java = JavaCall.get(name, fb.args(), qc, info);
    if(java != null) {
      final SeqType[] sts = new SeqType[arity];
      Arrays.fill(sts, Types.ITEM_ZM);
      final SeqType st = FuncType.get(fb.anns, null, sts).seqType();
      return new FuncLit(info, java, fb.params, fb.anns, st, name, fb.vs);
    }
    if(runtime) return null;

    throw qc.functions.unknownFunctionError(name, arity, info);
  }

  /**
   * Returns the actual function name of a function call or named function reference. For an