Merge pull request #15472 from mkouba/qute-letsection-docs

Qute - clarify that literals can be used in Let/Set section

docs/src/main/asciidoc/qute-reference.adoc

@@ -348,7 +348,7 @@ NOTE: The current context can be accessed via the implicit binding `this`.
 
 |Elvis Operator
 |Outputs the default value if the previous part cannot be resolved or resolves to `null`.
-|`{person.name ?: 'John'}`, `{person.name or 'John'}`
+|`{person.name ?: 'John'}`, `{person.name or 'John'}`, `{person.name.or('John')}`
 
 |orEmpty
 |Outputs an empty list if the previous part cannot be resolved or resolves to `null`.
@@ -370,7 +370,7 @@ NOTE: The current context can be accessed via the implicit binding `this`.
 
 TIP: The condition in a ternary operator evaluates to `true` if the value is not considered `falsy` as described in the <<if_section>>.
 
-NOTE: In fact, the operators are implemented as "virtual methods" that consume one parameter and can be used with infix notation, i.e. `{person.name or 'John'}` is translated to `{person.name.or('John')}`.
+NOTE: In fact, the operators are implemented as "virtual methods" that consume one parameter and can be used with infix notation. For example `{person.name or 'John'}` is translated to `{person.name.or('John')}` and `{item.isActive ? item.name : 'Inactive item'}` is translated to `{item.isActive.ifTruthy(item.name).or('Inactive item')}`
 
 ==== Arrays
 
@@ -780,10 +780,13 @@ This section might also come in handy when we'd like to avoid multiple expensive
 This section allows you to define named local variables:
 [source,html]
 ----
-{#let myParent=order.item.parent}
+{#let myParent=order.item.parent isActive=false age=10} <1>
   <h1>{myParent.name}</h1>
+  Is active: {isActive}
+  Age: {age}
 {/let}
 ----
+<1> The local variable is initialized with an expression that can also represent a <<literals,literal>>.
 
 The section tag is also registered under the `set` alias:
 

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

@@ -1100,7 +1100,7 @@ TemplateVariantsBuildItem collectTemplateVariants(List<TemplatePathBuildItem> te
     @BuildStep
     void excludeTypeChecks(QuteConfig config, BuildProducer<TypeCheckExcludeBuildItem> excludes) {
         // Exclude all checks that involve built-in value resolvers
-        List<String> skipOperators = Arrays.asList("?:", "or", ":", "?", "&&", "||");
+        List<String> skipOperators = Arrays.asList("?:", "or", ":", "?", "ifTruthy", "&&", "||");
         excludes.produce(new TypeCheckExcludeBuildItem(new Predicate<TypeCheck>() {
             @Override
             public boolean test(TypeCheck check) {

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

@@ -79,7 +79,7 @@ public CompletionStage<Object> resolve(EvalContext context) {
     }
 
     /**
-     * Returns the default value if the base object is null or {@link Result#NOT_FOUND}.
+     * Returns the default value if the base object is null or {@link Result#NOT_FOUND} and the base object otherwise.
      * 
      * {@code foo.or(bar)}, {@code foo or true}, {@code name ?: 'elvis'}
      */
@@ -133,6 +133,8 @@ public CompletionStage<Object> resolve(EvalContext context) {
     }
 
     /**
+     * Returns {@link Result#NOT_FOUND} if the base object is falsy and the base object otherwise.
+     * <p>
      * Can be used together with {@link #orResolver()} to form a ternary operator.
      * 
      * {@code person.isElvis ? 'elvis' : notElvis}
@@ -141,8 +143,16 @@ public static ValueResolver trueResolver() {
         return new ValueResolver() {
 
             public boolean appliesTo(EvalContext context) {
-                return context.getParams().size() == 1
-                        && ("?".equals(context.getName()));
+                if (context.getParams().size() != 1) {
+                    return false;
+                }
+                switch (context.getName()) {
+                    case "?":
+                    case "ifTruthy":
+                        return true;
+                    default:
+                        return false;
+                }
             }
 
             @Override

independent-projects/qute/core/src/test/java/io/quarkus/qute/SetSectionTest.java

@@ -20,4 +20,15 @@ public void testLet() {
                 engine.parse("{foo}:{baz} - {#let foo=true bar='mix'}{foo}:{bar}:{baz}{/}").data("baz", "what?!").render());
     }
 
+    @Test
+    public void testLiterals() {
+        Engine engine = Engine.builder().addDefaults().addValueResolver(new ReflectionValueResolver()).build();
+        assertEquals("1::4::Andy::false",
+                engine.parse(
+                        "{#let foo=1 bar='qute' baz=name.or('Andy') alpha=name.ifTruthy('true').or('false')}"
+                                + "{#for i in foo}{count}{/for}::{bar.length}::{baz}::{alpha}"
+                                + "{/let}")
+                        .render());
+    }
+
 }