Support bidirectional effects

effekt-lang · Nov 28, 2023 · 4be8355 · 4be8355
1 parent 74d4158
commit 4be8355
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Showing 3 changed files with 20 additions and 7 deletions.
diff --git a/effekt/jvm/src/test/scala/effekt/JavaScriptTests.scala b/effekt/jvm/src/test/scala/effekt/JavaScriptTests.scala
@@ -30,12 +30,7 @@ class JavaScriptTests extends EffektTests {
     // ---------------------------------------------
 
     // trampolining
-    examplesDir / "pos" / "stacksafe.effekt",
-
-    // bidirectional
-    examplesDir / "pos" / "bidirectional" / "iterators.effekt",
-    examplesDir / "pos" / "bidirectional" / "pingpong.effekt",
-
+    examplesDir / "pos" / "stacksafe.effekt"
   )
 }
 

diff --git a/effekt/shared/src/main/scala/effekt/generator/js/TransformerDS.scala b/effekt/shared/src/main/scala/effekt/generator/js/TransformerDS.scala
@@ -234,7 +234,21 @@ object TransformerDS {
 
   def toJS(handler: core.Implementation, prompt: JSName)(using DeclarationContext, Locals, Continuations, Context): js.Expr =
     js.Object(handler.operations.map {
-      // () => $effekt.suspend(this, (resume_730) => { return $effekt.unit; })
+      // (args...cap...) => $effekt.suspend(prompt, (resume) => { ... body ... resume((cap...) => { ... }) ... })
+      case Operation(id, tps, cps, vps, bps,
+          Some(BlockParam(resume, core.BlockType.Function(_, _, _, List(core.BlockType.Function(_, _, _, bidirectionalTpes, _)), _), _)),
+          body) =>
+        // add parameters for bidirectional arguments
+        val biParams = bidirectionalTpes.map { _ => freshName("cap") }
+        val biArgs   = biParams.map { p => js.Variable(p) }
+
+        val lambda = js.Lambda((vps ++ bps).map(toJS) ++ biParams,
+          js.Return(js.builtin("suspend_bidirectional", js.Variable(prompt), js.ArrayLiteral(biArgs), js.Lambda(List(nameDef(resume)),
+            js.Block(toJS(body)(x => js.Return(x)))))))
+
+        nameDef(id) -> lambda
+
+      // (args...) => $effekt.suspend(prompt, (resume) => { ... BODY ... resume(v) ... })
       case Operation(id, tps, cps, vps, bps, Some(resume), body) =>
         val lambda = js.Lambda((vps ++ bps) map toJS,
           js.Return(js.builtin("suspend", js.Variable(prompt), js.Lambda(List(toJS(resume)), js.Block(toJS(body)(x => js.Return(x)))))))

diff --git a/libraries/js/effekt_runtime.js b/libraries/js/effekt_runtime.js
@@ -1,6 +1,7 @@
 const $runtime = (function() {
 
   // Regions
+  // TODO maybe use weak refs (https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/WeakRef)
   function Cell(init) {
     var _value = init;
     const cell = ({
@@ -178,6 +179,9 @@ function Arena() {
     suspend: function(prompt, body) {
       throw new Suspension(prompt, body, Nil, Empty)
     },
+    suspend_bidirectional: function(prompt, caps, body) {
+      throw new Suspension(prompt, body, Cons(thunk => thunk.apply(null, caps), Nil), Empty)
+    },
 
     push: function(suspension, frame) {
       // Assuming `suspension` is a value or variable you want to return