Generate BuiltinMethods from simple method and constructor signatures (…

…#3444)

A low-hanging fruit where we can automate the generation of many
@BuiltinMethod nodes simply from the runtime's methods signatures.
This change introduces another annotation, @Builtin, to distinguish from
@BuiltinType and @BuiltinMethod processing. @Builtin processing will
always be the first stage of processing and its output will be fed to
the latter.

Note that the return type of Array.length() is changed from `int` to
`long` because we probably don't want to add a ton of specializations
for the former (see comparator nodes for details) and it is fine to cast
it in a small number of places.

Progress is visible in the number of deleted hardcoded classes.

This is an incremental step towards #181499077.

# Important Notes
This process does not attempt to cover all cases. Not yet, at least.
We only handle simple methods and constructors (see removed `Array` boilerplate methods).

CHANGELOG.md

@@ -199,6 +199,8 @@
 - [Frgaal compiler integration to allow for latest Java constructs][3421]
 - [Support for Chrome developer tools --inspect option][3432]
 - [Move Builtin Types and Methods definitions to stdlib][3363]
+- [Reduce boilerplate by generating BuiltinMethod nodes from simple method
+  signatures][3444]
 
 [3227]: https://github.com/enso-org/enso/pull/3227
 [3248]: https://github.com/enso-org/enso/pull/3248
@@ -216,6 +218,7 @@
 [3421]: https://github.com/enso-org/enso/pull/3421
 [3432]: https://github.com/enso-org/enso/pull/3432
 [3363]: https://github.com/enso-org/enso/pull/3363
+[3444]: https://github.com/enso-org/enso/pull/3444
 
 # Enso 2.0.0-alpha.18 (2021-10-12)
 

build.sbt

@@ -977,6 +977,7 @@ lazy val searcher = project
 lazy val `interpreter-dsl` = (project in file("lib/scala/interpreter-dsl"))
   .settings(
     version := "0.1",
+    frgaalJavaCompilerSetting,
     libraryDependencies ++= Seq(
       "org.apache.commons"      % "commons-lang3" % commonsLangVersion,
       "org.netbeans.api" % "org-openide-util-lookup" % "RELEASE130"
@@ -1221,7 +1222,8 @@ lazy val runtime = (project in file("engine/runtime"))
   .settings(
     (Compile / javacOptions) ++= Seq(
       "-s",
-      (Compile / sourceManaged).value.getAbsolutePath
+      (Compile / sourceManaged).value.getAbsolutePath,
+      "-Xlint:unchecked"
     ),
     addCompilerPlugin(
       "org.typelevel" %% "kind-projector" % kindProjectorVersion cross CrossVersion.full

engine/runtime/src/main/java/org/enso/interpreter/node/expression/builtin/mutable/SortNode.java

@@ -51,7 +51,7 @@ Object doAtomThis(VirtualFrame frame, Atom _this, Object that) {
 
   Object runSort(Comparator<Object> compare, Array _this, Context context) {
     doSort(_this.getItems(), compare);
-    LoopNode.reportLoopCount(this, _this.length());
+    LoopNode.reportLoopCount(this, (int) _this.length());
     return context.getBuiltins().nothing().newInstance();
   }
 

engine/runtime/src/main/java/org/enso/interpreter/node/expression/builtin/warning/SetWarningsNode.java

@@ -25,7 +25,7 @@ Object doWarning(Object _this, WithWarnings value, Array warnings) {
     if (warnings.length() == 0) {
       return value.getValue();
     }
-    Warning[] warningsCast = new Warning[warnings.length()];
+    Warning[] warningsCast = new Warning[(int) warnings.length()];
     System.arraycopy(warnings.getItems(), 0, warningsCast, 0, warningsCast.length);
     return new WithWarnings(value.getValue(), warningsCast);
   }
@@ -35,7 +35,7 @@ Object doOther(Object _this, Object value, Array warnings) {
     if (warnings.length() == 0) {
       return value;
     }
-    Warning[] warningsCast = new Warning[warnings.length()];
+    Warning[] warningsCast = new Warning[(int) warnings.length()];
     System.arraycopy(warnings.getItems(), 0, warningsCast, 0, warningsCast.length);
     return new WithWarnings(value, warningsCast);
   }

engine/runtime/src/main/java/org/enso/interpreter/runtime/builtin/Builtins.java

@@ -261,6 +261,7 @@ private Map<String, Map<String, Class<BuiltinRootNode>>> readBuiltinMethodsMetad
             throw new CompilerError("Invalid builtin metadata in : " + line);
           }
           try {
+            @SuppressWarnings("unchecked")
             Class<BuiltinRootNode> clazz = (Class<BuiltinRootNode>) Class.forName(builtinMeta[1]);
             String builtinMethodOwner = builtinName[0];
             String builtinMethodName = builtinName[1];

engine/runtime/src/main/java/org/enso/interpreter/runtime/data/Array.java

@@ -8,6 +8,8 @@
 import com.oracle.truffle.api.interop.TruffleObject;
 import com.oracle.truffle.api.library.ExportLibrary;
 import com.oracle.truffle.api.library.ExportMessage;
+import org.enso.interpreter.dsl.Builtin;
+import org.enso.interpreter.dsl.BuiltinMethod;
 import org.enso.interpreter.runtime.Context;
 import org.enso.interpreter.runtime.callable.UnresolvedConversion;
 import org.enso.interpreter.runtime.callable.UnresolvedSymbol;
@@ -37,6 +39,7 @@ public Array(Object... items) {
    *
    * @param size the size of the created array.
    */
+  @Builtin(pkg = "mutable", description = "Creates an uninitialized array of a given size.")
   public Array(long size) {
     this.items = new Object[(int) size];
   }
@@ -72,8 +75,23 @@ public Object readArrayElement(long index) throws InvalidArrayIndexException {
   }
 
   /** @return the size of this array */
-  public int length() {
-    return this.items.length;
+  @Builtin(pkg = "mutable", description = "Returns the size of this array.")
+  public long length() {
+    return this.getItems().length;
+  }
+
+  /** @return an empty array */
+  @Builtin(pkg = "mutable", description = "Creates an empty Array")
+  public static Object empty() {
+    return new Array();
+  }
+
+  /** @return an identity array */
+  @Builtin(
+      pkg = "mutable",
+      description = "Identity on arrays, implemented for protocol completeness.")
+  public Object toArray() {
+    return this;
   }
 
   /**

lib/scala/interpreter-dsl/src/main/java/org/enso/interpreter/dsl/Builtin.java

@@ -0,0 +1,20 @@
+package org.enso.interpreter.dsl;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+/** An annotation denoting a method that will auto-generate a BuiltinMethod node. */
+@Target({ElementType.METHOD, ElementType.CONSTRUCTOR})
+@Retention(RetentionPolicy.SOURCE)
+public @interface Builtin {
+  /** @return the name of the subpackage for the generated method node. */
+  String pkg() default "";
+
+  /** @return a custom name, by default it uses the name of the annotated element. */
+  String name() default "";
+
+  /** @return a short description of this method. */
+  String description() default "";
+}

lib/scala/interpreter-dsl/src/main/java/org/enso/interpreter/dsl/BuiltinsMetadataProcessor.java

@@ -4,6 +4,7 @@
 import javax.annotation.processing.RoundEnvironment;
 import javax.lang.model.element.Element;
 import javax.lang.model.element.TypeElement;
+import javax.tools.Diagnostic;
 import javax.tools.FileObject;
 import javax.tools.StandardLocation;
 import java.io.*;
@@ -76,9 +77,10 @@ public final boolean process(Set<? extends TypeElement> annotations, RoundEnviro
           writer.close();
         }
       } catch (IOException e) {
-        e.printStackTrace();
+        processingEnv.getMessager().printMessage(Diagnostic.Kind.ERROR, e.getMessage());
+      } finally {
+        cleanup();
       }
-      cleanup();
       return true;
     } else {
       return handleProcess(annotations, roundEnv);