Macro for feature flag

TODO.md

@@ -7,7 +7,7 @@ Trying to reimplement the destructuring feature better (see #524 for a full intr
 ## TODO
 
 - [x] implement the new desugarization
-  - [ ] allows to explicitly skip the rest (e.g. with special arg `_`) to avoid generating an unused (recursive) member
+  - [x] allows to explicitly skip the rest (e.g. with special arg `_`) to avoid generating an unused (recursive) member
 - [x] Adds a custom exception to signal invalid destructuring
 - update the known `destruct()` method in the stdlib
   - provides a new destructuring method
@@ -22,8 +22,8 @@ Trying to reimplement the destructuring feature better (see #524 for a full intr
     - [x] ranges
     - [x] When IR
   - [x] mark the old one deprecated (may depend on PR #551 to annotate golo code)
-    - [ ] use the real deprecated macro when #551 is merged
-- [ ] provides augmentations to adapt both ways ?
+    - [x] use the real deprecated macro when #551 is merged
+- [ ] ~~provides augmentations to adapt both ways ?~~
 - [ ] update the doc
   - [ ] describe new style destruct
   - [ ] rationale

src/main/golo/gololang/macros.golo

@@ -140,3 +140,16 @@ macro deprecated = |args...| {
       named: get("comment")?: value(),
       positional)
 }
+
+----
+Use old-style destructuring for the current module.
+
+This macro customize the behavior of the destructuring feature by forcing the use of the `destruct` method instead of
+`_$$_destruct`.
+
+This is a toplevel macro.
+----
+@contextual
+macro useOldstyleDestruct = |self| {
+  self: enclosingModule(): metadata("golo.destruct.newstyle", false)
+}

src/main/java/org/eclipse/golo/compiler/SugarExpansionVisitor.java

@@ -11,6 +11,7 @@
 package org.eclipse.golo.compiler;
 
 import gololang.ir.*;
+import gololang.Messages;
 import java.util.List;
 import java.util.Deque;
 import java.util.LinkedList;
@@ -30,7 +31,13 @@ class SugarExpansionVisitor extends AbstractGoloIrVisitor {
   private final SymbolGenerator symbols = new SymbolGenerator("golo.compiler.sugar");
   private final List<GoloFunction> functionsToAdd = new LinkedList<>();
   private GoloModule module;
-  private final boolean useNewStyleDestruct = gololang.Runtime.loadBoolean("new", "golo.destruct.version", "GOLO_DESTRUCT_VERSION", true);
+
+  private boolean useNewStyleDestruct() {
+    if (this.module.metadata("golo.destruct.newstyle") != null) {
+      return (boolean) this.module.metadata("golo.destruct.newstyle");
+    }
+    return gololang.Runtime.loadBoolean("true", "golo.destruct.newstyle", "GOLO_DESTRUCT_NEWSTYLE", true);
+  }
 
   @Override
   public void visitModule(GoloModule module) {
@@ -380,7 +387,7 @@ public void visitForEachLoopStatement(ForEachLoopStatement foreachStatement) {
    */
   @Override
   public void visitDestructuringAssignment(DestructuringAssignment assignment) {
-    Block replacement = useNewStyleDestruct ? newDestructuring(assignment) : oldDestructuring(assignment);
+    Block replacement = useNewStyleDestruct() ? newDestructuring(assignment) : oldDestructuring(assignment);
     assignment.replaceInParentBy(replacement);
     replacement.accept(this);
   }
@@ -402,6 +409,7 @@ public void visitDestructuringAssignment(DestructuringAssignment assignment) {
    * </code></pre>
    */
   private Block oldDestructuring(DestructuringAssignment assignment) {
+    Messages.warning(Messages.message("oldstyle_destruct", this.module.getPackageAndClass()), assignment);
     LocalReference tmpRef = LocalReference.of(symbols.next("destruct")).synthetic();
     Block block = Block.of(AssignmentStatement.create(tmpRef, invoke("destruct").on(assignment.expression()), true));
     int last = assignment.getReferencesCount() - 1;

src/main/resources/messages.properties

@@ -81,6 +81,7 @@ no_parameter_names = The function `{0}` has no parameter names but is called wit
 unavailable_class = `{0}` used in `{1}` can\u2019t be loaded.\n\tSee <{2}#warning-unavailable-class> for more information.
 
 deprecated_element = `{0}` in `{1}` is deprecated.\n\tSee <{2}#warning-deprecated> for more information.
+oldstyle_destruct = `{0}` uses old-style destructuring, which is deprecated.
 
 # Documentation warnings and errors ===========================================
 multiple_package_desc = Multiple description files found for package `{0}`; using the first one.\n\tSee <{1}#warning-multiple-package-desc> for more information.

src/main/resources/messages_fr_FR.properties

@@ -81,6 +81,7 @@ struct_private_member = Membre priv\u00e9 de `{0}`
 no_parameter_names = La fonction `{0}` n\u2019a pas de param\u00e8tre nomm\u00e9 mais est appel\u00e9e avec {1} comme noms d\u2019arguments.\n\tVoir <{2}#warning-no-parameter-names> pour plus d\u2019informations.
 unavailable_class = `{0}` utilis\u00e9e dans `{1}` ne peut pas \u00eatre charg\u00e9e.\n\tVoir <{2}#warning-unavailable-class> pour plus d\u2019informations.
 deprecated_element = `{0}` dans `{1}` est obsol\u00e8te.\n\tVoir <{2}#warning-deprecated> pour plus d\u2019informations.
+oldstyle_destruct = `{0}` utilise l\u2019ancienne version de la d\u00e9structuration qui est obsol\u00e8te.
 
 # Documentation warnings and errors ===========================================
 multiple_package_desc = Fichiers de description surnum\u00e9raires pour le paquet `{0}`; utilisation du premier.\n\tVoir <{1}#warning-multiple-package-desc> pour plus d\u2019informations.

src/test/java/org/eclipse/golo/compiler/CompileAndRunTest.java

@@ -1771,15 +1771,8 @@ public void destructuring() throws Throwable {
     if (bootstraping()) {
       return;
     }
-    Class<?> moduleClass = compileAndLoadGoloModule(SRC, "destruct.golo");
-    for (Method testMethod : getTestMethods(moduleClass)) {
-      try {
-        testMethod.invoke(null);
-      } catch (InvocationTargetException e) {
-        fail("method " + testMethod.getName() + " in " + SRC + "destruct.golo failed: " +
-              e.getCause());
-      }
-    }
+    runTests(SRC, "destruct.golo", classLoader(this));
+    runTests(SRC, "destruct-old.golo", classLoader(this));
   }
 
   @Test

src/test/resources/for-execution/destruct-old.golo

@@ -0,0 +1,25 @@
+module golotest.execution.DestructuringOld
+
+import org.hamcrest.MatcherAssert
+import org.hamcrest.Matchers
+
+import org.eclipse.golo.runtime
+
+&useOldstyleDestruct()
+
+function test_tuple_old = {
+  let fst, scd = [1, 2, 3, 4]
+  assertThat(fst, `is(1))
+  assertThat(scd, `is(2))
+}
+
+function test_list_old = {
+  let a, b... = list[1, 2, 3, 4]
+  assertThat(a, `is(1))
+  assertThat(b, `is(tuple[2, 3, 4]))
+}
+
+function main = |args| {
+  test_tuple_old()
+  test_list_old()
+}

src/test/resources/for-execution/destruct.golo

@@ -48,13 +48,6 @@ function test_tuple_rest = {
   assertThat(c, `is([3, 4, 5]))
 }
 
-# ignored, old version. Should fail now.
-function _tuple_less_old = {
-  let fst, scd = [1, 2, 3, 4]
-  require(fst == 1, "err")
-  require(scd == 2, "err")
-}
-
 function test_tuple_less_new = {
   try {
     let fst, scd = [1, 2, 3, 4]