Qute: template extensions can use regular expressions to match names

- also implement a shortcut to access List elements by index
- resolves quarkusio#11275

extensions/qute/deployment/src/main/java/io/quarkus/qute/deployment/QuteProcessor.java

@@ -625,7 +625,12 @@ private void produceExtensionMethod(IndexView index, BuildProducer<TemplateExten
         if (namespaceValue != null) {
             namespace = namespaceValue.asString();
         }
-        extensionMethods.produce(new TemplateExtensionMethodBuildItem(method, matchName,
+        String matchRegex = null;
+        AnnotationValue matchRegexValue = extensionAnnotation.value(ExtensionMethodGenerator.MATCH_REGEX);
+        if (matchRegexValue != null) {
+            matchRegex = matchRegexValue.asString();
+        }
+        extensionMethods.produce(new TemplateExtensionMethodBuildItem(method, matchName, matchRegex,
                 index.getClassByName(method.parameters().get(0).name()), priority, namespace));
     }
 
@@ -803,7 +808,7 @@ public boolean test(String name) {
             } else {
                 // Generate ValueResolver per extension method
                 extensionMethodGenerator.generate(templateExtension.getMethod(), templateExtension.getMatchName(),
-                        templateExtension.getPriority());
+                        templateExtension.getMatchRegex(), templateExtension.getPriority());
             }
         }
 
@@ -815,7 +820,7 @@ public boolean test(String name) {
                     .createNamespaceResolver(methods.get(0).getMethod().declaringClass(), methods.get(0).getNamespace())) {
                 try (ResolveCreator resolveCreator = namespaceResolverCreator.implementResolve()) {
                     for (TemplateExtensionMethodBuildItem method : methods) {
-                        resolveCreator.addMethod(method.getMethod(), method.getMatchName());
+                        resolveCreator.addMethod(method.getMethod(), method.getMatchName(), method.getMatchRegex());
                     }
                 }
             }

extensions/qute/deployment/src/main/java/io/quarkus/qute/deployment/TemplateExtensionMethodBuildItem.java

@@ -1,5 +1,7 @@
 package io.quarkus.qute.deployment;
 
+import java.util.regex.Pattern;
+
 import org.jboss.jandex.ClassInfo;
 import org.jboss.jandex.MethodInfo;
 
@@ -15,17 +17,22 @@ public final class TemplateExtensionMethodBuildItem extends MultiBuildItem {
 
     private final MethodInfo method;
     private final String matchName;
+    private final String matchRegex;
+    private final Pattern matchPattern;
     private final ClassInfo matchClass;
     private final int priority;
     private final String namespace;
 
-    public TemplateExtensionMethodBuildItem(MethodInfo method, String matchName, ClassInfo matchClass, int priority,
+    public TemplateExtensionMethodBuildItem(MethodInfo method, String matchName, String matchRegex, ClassInfo matchClass,
+            int priority,
             String namespace) {
         this.method = method;
         this.matchName = matchName;
+        this.matchRegex = matchRegex;
         this.matchClass = matchClass;
         this.priority = priority;
         this.namespace = namespace;
+        this.matchPattern = (matchRegex == null || matchRegex.isEmpty()) ? null : Pattern.compile(matchRegex);
     }
 
     public MethodInfo getMethod() {
@@ -36,6 +43,10 @@ public String getMatchName() {
         return matchName;
     }
 
+    public String getMatchRegex() {
+        return matchRegex;
+    }
+
     public ClassInfo getMatchClass() {
         return matchClass;
     }
@@ -53,6 +64,9 @@ boolean matchesClass(ClassInfo clazz) {
     }
 
     boolean matchesName(String name) {
+        if (matchPattern != null) {
+            return matchPattern.matcher(name).matches();
+        }
         return TemplateExtension.ANY.equals(matchName) ? true : matchName.equals(name);
     }
 

extensions/qute/deployment/src/test/java/io/quarkus/qute/deployment/extensions/NamespaceTemplateExtensionTest.java

@@ -30,6 +30,8 @@ public void testTemplateExtensions() {
                 engine.parse("{str:format('%s:%s','hello', 1)}").render());
         assertEquals("olleh",
                 engine.parse("{str:reverse('hello')}").render());
+        assertEquals("foolish:olleh",
+                engine.parse("{str:foolish('hello')}").render());
         assertEquals("ONE=ONE",
                 engine.parse("{MyEnum:ONE}={MyEnum:one}").render());
     }
@@ -45,6 +47,11 @@ static String reverse(String val) {
             return new StringBuilder(val).reverse().toString();
         }
 
+        @TemplateExtension(namespace = "str", matchRegex = "foo.*")
+        static String foo(String name, String val) {
+            return name + ":" + new StringBuilder(val).reverse().toString();
+        }
+
     }
 
     public enum MyEnum {

extensions/qute/deployment/src/test/java/io/quarkus/qute/deployment/extensions/TemplateExtensionMethodsTest.java

@@ -5,6 +5,7 @@
 
 import java.math.BigDecimal;
 import java.math.RoundingMode;
+import java.util.Collections;
 import java.util.HashMap;
 import java.util.Map;
 
@@ -80,6 +81,12 @@ public void testPriority() {
         assertEquals("bravo::baz", engine.getTemplate("priority").data("foo", new Foo("baz", 10l)).render());
     }
 
+    @Test
+    public void testListGetByIndex() {
+        assertEquals("true=true=NOT_FOUND",
+                engine.parse("{list.0}={list[0]}={list[100]}").data("list", Collections.singletonList(true)).render());
+    }
+
     @TemplateExtension
     public static class Extensions {
 

extensions/qute/runtime/src/main/java/io/quarkus/qute/runtime/extensions/CollectionTemplateExtensions.java

@@ -2,6 +2,7 @@
 
 import java.util.List;
 
+import io.quarkus.qute.Results.Result;
 import io.quarkus.qute.TemplateExtension;
 
 @TemplateExtension
@@ -10,4 +11,14 @@ public class CollectionTemplateExtensions {
     static Object get(List<?> list, int index) {
         return list.get(index);
     }
-}
+
+    @TemplateExtension(matchRegex = "\\d{1,10}")
+    static Object getByIndex(List<?> list, String index) {
+        int idx = Integer.parseInt(index);
+        if (idx >= list.size()) {
+            // Be consistent with property resolvers
+            return Result.NOT_FOUND;
+        }
+        return list.get(idx);
+    }
+}

independent-projects/qute/core/src/main/java/io/quarkus/qute/TemplateExtension.java

@@ -9,23 +9,29 @@
 
 /**
  * A value resolver is automatically generated for a method annotated with this annotation. If declared on a class a value
- * resolver is generated for every non-private static method declared on the class. Methods that do not meet the following
- * requirements are ignored.
+ * resolver is generated for every non-private static method declared on the class. Method-level annotations override the
+ * behavior defined on the class.
+ * <p>
+ * Methods that do not meet the following requirements are ignored.
  * <p>
  * A template extension method:
  * <ul>
  * <li>must be static,</li>
  * <li>must not return {@code void},</li>
  * <li>must accept at least one parameter, unless the namespace is specified.</li>
- * <p>
+ * </ul>
  * The class of the first parameter is used to match the base object unless the namespace is specified. In such case, the
  * namespace is used to match an expression.
  * <p>
  * By default, the method name is used to match the property name. However, it is possible to specify the matching name with
  * {@link #matchName()}. A special constant - {@link #ANY} - may be used to specify that the extension method matches any name.
- * In that case, a method parameter is used to pass the property name. If a namespace is specified the method must declare at
- * least one parameter and the first parameter must be a string. If no namespace is specified the method must declare at least
- * two parameters and the second parameter must be a string.
+ * It is also possible to match the name against a regular expression specified in {@link #matchRegex()}. In both cases, a
+ * string method parameter is used to pass the property name.
+ * <p>
+ * If both {@link #matchName()} and {@link #matchRegex()} are set the regular expression is used for matching.
+ * <p>
+ * If a namespace is specified the method must declare at least one parameter and the first parameter must be a string. If no
+ * namespace is specified the method must declare at least two parameters and the second parameter must be a string.
  * 
  * <pre>
  * {@literal @}TemplateExtension
@@ -60,6 +66,12 @@
      */
     String matchName() default METHOD_NAME;
 
+    /**
+     * 
+     * @return the regex is used to match the property name
+     */
+    String matchRegex() default "";
+
     /**
      * 
      * @return the priority used by the generated value resolver
@@ -70,7 +82,8 @@
      * If not empty a namespace resolver is generated instead.
      * <p>
      * Template extension methods that share the same namespace and are declared on the same class are grouped in one resolver
-     * ordered by {@link #priority()}. The first matching extension method is used to resolve an expression. Template extension
+     * and ordered by {@link #priority()}. The first matching extension method is used to resolve an expression. Template
+     * extension
      * methods declared on different classes cannot share the same namespace.
      * 
      * @return the namespace

independent-projects/qute/generator/src/main/java/io/quarkus/qute/generator/Descriptors.java

@@ -12,6 +12,8 @@
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.CompletionStage;
 import java.util.function.BiConsumer;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
 
 public final class Descriptors {
 
@@ -66,6 +68,12 @@ private Descriptors() {
     static final MethodDescriptor EVALUATED_PARAMS_GET_VARARGS_RESULTS = MethodDescriptor.ofMethod(EvaluatedParams.class,
             "getVarargsResults", Object.class, int.class,
             Class.class);
+    public static final MethodDescriptor PATTERN_COMPILE = MethodDescriptor.ofMethod(Pattern.class, "compile", Pattern.class,
+            String.class);
+    public static final MethodDescriptor PATTERN_MATCHER = MethodDescriptor.ofMethod(Pattern.class, "matcher", Matcher.class,
+            CharSequence.class);
+    public static final MethodDescriptor MATCHER_MATCHES = MethodDescriptor.ofMethod(Matcher.class, "matches", boolean.class);
+    public static final MethodDescriptor OBJECT_CONSTRUCTOR = MethodDescriptor.ofConstructor(Object.class);
 
     public static final FieldDescriptor RESULTS_NOT_FOUND = FieldDescriptor.of(Results.class, "NOT_FOUND",
             CompletionStage.class);