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https://issues.apache.org/jira/browse/JENA-1372?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16133018#comment-16133018
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ASF GitHub Bot commented on JENA-1372:
--------------------------------------
Github user ajs6f commented on a diff in the pull request:
https://github.com/apache/jena/pull/273#discussion_r133970438
--- Diff:
jena-arq/src/main/java/org/apache/jena/sparql/function/library/FN_Apply.java ---
@@ -0,0 +1,96 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.jena.sparql.function.library;
+
+import java.util.List ;
+
+import org.apache.jena.atlas.lib.Cache ;
+import org.apache.jena.atlas.lib.CacheFactory ;
+import org.apache.jena.graph.Node ;
+import org.apache.jena.sparql.expr.ExprEvalException ;
+import org.apache.jena.sparql.expr.ExprList ;
+import org.apache.jena.sparql.expr.NodeValue ;
+import org.apache.jena.sparql.function.Function ;
+import org.apache.jena.sparql.function.FunctionBase ;
+import org.apache.jena.sparql.function.FunctionFactory ;
+import org.apache.jena.sparql.function.FunctionRegistry ;
+import org.apache.jena.sparql.sse.builders.ExprBuildException ;
+import org.apache.jena.sparql.util.Context ;
+
+/** XPath and XQuery Functions and Operators 3.1
+ * <p>
+ * {@code fn:apply(function, args)}
+ */
+public class FN_Apply extends FunctionBase {
+ // Assumes one object per use site.
+ private Cache<String, Function> cache1 =
CacheFactory.createOneSlotCache();
+
+ @Override
+ public void checkBuild(String uri, ExprList args) {
+ if ( args.isEmpty() )
+ throw new ExprBuildException("fn:apply: no function to call
(minimum number of args is one)");
+ }
+ @Override
+ public NodeValue exec(List<NodeValue> args) {
+ if ( args.isEmpty() )
+ throw new ExprBuildException("fn:apply: no function to call
(minimum number of args is one)");
+ NodeValue functionId = args.get(0);
+ List<NodeValue> argExprs = args.subList(1,args.size()) ;
+ ExprList exprs = new ExprList();
+ argExprs.forEach((a)->exprs.add(a));
--- End diff --
Maybe `argExprs.forEach(exprs::add);`?
It's not clear to me why not `ExprList exprs = new ExprList(argExprs);`.
I'm sure there's a reason-- I must be missing something in the execution flow?
Why copy instead of view?
> New functions in F&O 3.1
> ------------------------
>
> Key: JENA-1372
> URL: https://issues.apache.org/jira/browse/JENA-1372
> Project: Apache Jena
> Issue Type: Improvement
> Components: ARQ
> Affects Versions: Jena 3.4.0
> Reporter: Andy Seaborne
> Priority: Minor
>
> F&O 3.1 adds some new functions : see
> https://www.w3.org/TR/xpath-functions-3/#substantive-changes.
> The ones of note are:
> * [fn:apply|https://www.w3.org/TR/xpath-functions-3/#func-apply] (dynamically
> applies a function to arguments supplied as an array) which is close to the
> extension {{CALL}}, so the code there could be extracted and morphed to be
> {{fn:apply}}.
> *
> [fn:collation-key|https://www.w3.org/TR/xpath-functions-3/#func-collation-key]
> (generates a key that can be used for collation-based matching). It is quite
> similar to role played by {{NodeValueSortKey}}.
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