Merge pull request #163 from effekt-lang/feature/machine-evidence

Machine: Fix arity mismatch with effect handlers due to evidence
effekt-lang · Sep 30, 2022 · 46952f1 · 46952f1
2 parents 45f3f99 + 199dbf9
commit 46952f1
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Showing 2 changed files with 7 additions and 10 deletions.
diff --git a/effekt/jvm/src/test/scala/effekt/LLVMTests.scala b/effekt/jvm/src/test/scala/effekt/LLVMTests.scala
@@ -13,13 +13,7 @@ class LLVMTests extends EffektTests {
 
   override lazy val ignored: List[File] = List(
     // computes the wrong results
-    examplesDir / "llvm" / "generator.effekt",
-    examplesDir / "llvm" / "capabilities.effekt",
     examplesDir / "llvm" / "nested.effekt",
-    examplesDir / "llvm" / "stored.effekt",
-
-    // crashes
-    examplesDir / "llvm" / "forking.effekt",
 
     // polymorphic effect operations not supported, yet
     examplesDir / "llvm" / "choice.effekt",

diff --git a/effekt/shared/src/main/scala/effekt/machine/Transformer.scala b/effekt/shared/src/main/scala/effekt/machine/Transformer.scala
@@ -127,7 +127,6 @@ object Transformer {
 
       case lifted.App(lifted.BlockVar(id), List(), args) =>
         // TODO deal with BlockLit
-        // TODO deal with evidence
         id match {
           case symbols.UserFunction(_, _, _, _, _, _, _) =>
             // TODO this is a hack, values is in general shorter than environment
@@ -142,9 +141,11 @@ object Transformer {
             }
           case symbols.ResumeParam(_) =>
             // TODO currently only scoped resumptions are supported
+            // TODO assuming first parameter is evidence TODO actually use evidence?
             transform(args).run { values =>
+              val (evidence :: returnedValues) = values;
               PushStack(Variable(transform(id), Type.Stack()),
-                Return(values))
+                Return(returnedValues))
             }
           case _ =>
             Context.abort(s"Unsupported blocksymbol: $id")
@@ -183,7 +184,6 @@ object Transformer {
         }
 
       case lifted.Handle(lifted.BlockLit(List(ev, id), body), tpe, List(handler)) =>
-        // TODO deal with evidence
         // TODO more than one handler
         val variable = Variable(freshName("a"), transform(tpe))
         val returnClause = Clause(List(variable), Return(List(variable)))
@@ -311,7 +311,10 @@ object Transformer {
       case lifted.Handler(_, List((operationName, lifted.BlockLit(params :+ resume, body)))) =>
         // TODO we assume here that resume is the last param
         // TODO we assume that there are no block params in handlers
-        List(Clause(params.map(transform),
+        // TODO we assume that evidence has to be passed as first param
+        // TODO actually use evidence to determine number of stacks popped
+        val ev = Variable(freshName("evidence"), builtins.Evidence)
+        List(Clause(ev +: params.map(transform),
           PopStack(Variable(transform(resume).name, Type.Stack()),
             transform(body))))
       case _ =>