Special Meta.Function to work as a handle to Function

distribution/lib/Standard/Base/0.0.0-dev/src/Meta.enso

@@ -11,6 +11,7 @@ import project.Data.Time.Time_Of_Day.Time_Of_Day
 import project.Data.Time.Time_Zone.Time_Zone
 import project.Data.Vector.Vector
 import project.Nothing.Nothing
+import project.Function.Function as Std_Function
 import project.Polyglot.Java
 
 import project.Error.Error as Base_Error
@@ -217,6 +218,20 @@ type Polyglot
         lang_str = get_polyglot_language self.value
         if lang_str == "java" then Language.Java else Language.Unknown
 
+type Function
+    ## PRIVATE
+    Value value
+
+    ## PRIVATE
+      ADVANCED
+
+      Given a type object, method name and a parameter name, return the associated annotation if it exists.
+
+      Arguments:
+      - parameter_name: The name of the parameter to get the attribute for.
+   get_annotation : Text -> Any
+   get_annotation self parameter_name = Meta.get_annotation self.value... Nothing parameter_name
+
 ## ADVANCED
 
    Checks whether `self` represents the same underlying reference as `value`.
@@ -366,13 +381,14 @@ atom_with_hole factory = @Builtin_Method "Meta.atom_with_hole_builtin"
    Arguments:
    - value: The runtime entity to get the meta representation of.
 meta : Any -> Atom | Constructor | Primitive | Polyglot | Unresolved_Symbol | Error
-meta value = if is_atom value then Atom.Value value else
-    if is_atom_constructor value then Constructor.Value value else
-        if is_polyglot value then Polyglot.Value value else
-            if is_unresolved_symbol value then Unresolved_Symbol.Value value else
-                if is_error value then Error.Value value.catch else
-                    if is_type value then Type.Value value.catch else
-                        Primitive.Value value
+meta value = if is_function value... then Function.Value value... else
+    if is_atom value then Atom.Value value else
+        if is_atom_constructor value then Constructor.Value value else
+            if is_polyglot value then Polyglot.Value value else
+                if is_unresolved_symbol value then Unresolved_Symbol.Value value else
+                    if is_error value then Error.Value value.catch else
+                        if is_type value then Type.Value value.catch else
+                           Primitive.Value value
 
 ## PRIVATE
    ADVANCED
@@ -457,6 +473,15 @@ is_atom_constructor value = @Builtin_Method "Meta.is_atom_constructor"
 is_atom : Any -> Boolean
 is_atom value = @Builtin_Method "Meta.is_atom"
 
+## PRIVATE
+
+   Checks if the provided value is a function.
+
+   Arguments:
+   - value: The value to check.
+is_function : Any -> Boolean
+is_function value = @Builtin_Method "Meta.is_function"
+
 ## PRIVATE
 
    Checks if the provided value is a runtime error.

engine/runtime/src/main/java/org/enso/interpreter/node/expression/builtin/meta/IsFunctionNode.java

@@ -0,0 +1,17 @@
+package org.enso.interpreter.node.expression.builtin.meta;
+
+import com.oracle.truffle.api.nodes.Node;
+import org.enso.interpreter.dsl.AcceptsError;
+import org.enso.interpreter.dsl.BuiltinMethod;
+import org.enso.interpreter.runtime.type.TypesGen;
+
+@BuiltinMethod(
+    type = "Meta",
+    name = "is_function",
+    description = "Checks if the argument is an function.",
+    autoRegister = false)
+public class IsFunctionNode extends Node {
+  boolean execute(@AcceptsError Object value) {
+    return TypesGen.isFunction(value);
+  }
+}

engine/runtime/src/main/java/org/enso/interpreter/runtime/scope/ModuleScope.java

@@ -1,15 +1,7 @@
 package org.enso.interpreter.runtime.scope;
 
-import com.oracle.truffle.api.CompilerDirectives.CompilationFinal;
 import com.oracle.truffle.api.CompilerDirectives.TruffleBoundary;
 import com.oracle.truffle.api.interop.TruffleObject;
-import org.enso.interpreter.runtime.EnsoContext;
-import org.enso.interpreter.runtime.Module;
-import org.enso.interpreter.runtime.callable.function.Function;
-import org.enso.interpreter.runtime.data.Type;
-import org.enso.interpreter.runtime.error.RedefinedMethodException;
-import org.enso.interpreter.runtime.error.RedefinedConversionException;
-
 import java.util.Collection;
 import java.util.HashMap;
 import java.util.HashSet;
@@ -18,6 +10,12 @@
 import java.util.Objects;
 import java.util.Optional;
 import java.util.Set;
+import org.enso.interpreter.runtime.EnsoContext;
+import org.enso.interpreter.runtime.Module;
+import org.enso.interpreter.runtime.callable.function.Function;
+import org.enso.interpreter.runtime.data.Type;
+import org.enso.interpreter.runtime.error.RedefinedConversionException;
+import org.enso.interpreter.runtime.error.RedefinedMethodException;
 
 /** A representation of Enso's per-file top-level scope. */
 public final class ModuleScope implements TruffleObject {
@@ -194,11 +192,14 @@ public Function lookupMethodDefinition(Type type, String name) {
       return definedHere;
     }
 
-    return imports.stream()
-        .map(scope -> scope.getExportedMethod(type, name))
-        .filter(Objects::nonNull)
-        .findFirst()
-        .orElse(null);
+    for (var scope : imports) {
+      var method = scope.getExportedMethod(type, name);
+      if (method != null) {
+        return method;
+      }
+    }
+
+    return null;
   }
 
   @TruffleBoundary

test/Tests/src/Semantic/Meta_Define_Usage.enso

@@ -6,6 +6,4 @@ call_describe_better it = it.describe_better
 annotate_describe_better it = Meta.get_annotation it "describe_better" "which"
 obtain_describe_better it =
     fn = it.describe_better...
-    anno = Meta.get_annotation fn... Nothing "which"
-    anno.is_nothing
-    fn...
+    Meta.meta fn

test/Tests/src/Semantic/Meta_Spec.enso

@@ -401,6 +401,13 @@ spec =
             Meta.type_of (_.is_nothing) . should_equal Function
             Meta.type_of (.is_nothing) . should_equal Function
 
+    Test.group "Meta for functions" <|
+        Test.specify "Meta for lambda" <|
+            fn_meta = Meta.meta (x-> 2 * x)
+            case fn_meta of
+                _ : Meta.Function -> Nothing
+                _ -> Test.fail "Expecting Meta.Function: " + (Meta.type_of fn_meta).to_text
+
     Test.group "Extension methods and get_annotation" <|
         it = Meta_Spec_Type.Value 6 7
 
@@ -411,15 +418,15 @@ spec =
             Meta_Define_Usage.call_describe_better it "mul" . should_equal 42
 
         Test.specify "verify calling everything works" <|
-            describe_anno = Meta.get_annotation it.describe... Nothing "which"
+            wrap = Meta.meta it.describe...
+            describe_anno = wrap.get_annotation "which"
             describe_anno it . should_equal 13
 
 
             # Meta_Define_Usage can resolve the describe_better method
-            fn = (Meta_Define_Usage.obtain_describe_better it)...
-            fn.is_nothing . should_be_false
+            meta_fn = Meta_Define_Usage.obtain_describe_better it
             # we can query annotations for the resolved function
-            describe_better_anno = Meta.get_annotation fn... Nothing "which"
+            describe_better_anno = meta_fn.get_annotation "which"
             describe_better_anno it . should_equal 13
 
 main = Test_Suite.run_main spec