Add specialized abort continuation

effekt-lang · Jan 22, 2025 · 07e2740 · 07e2740
1 parent 84beb0b
commit 07e2740
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Showing 3 changed files with 6 additions and 8 deletions.
diff --git a/effekt/shared/src/main/scala/effekt/cps/Transformer.scala b/effekt/shared/src/main/scala/effekt/cps/Transformer.scala
@@ -82,7 +82,7 @@ object Transformer {
       App(transform(callee), vargs.map(transform), bargs.map(transform), MetaCont(ks), k.reify)
 
     case core.Stmt.Invoke(callee, method, tpe, targs, vargs, bargs) if stmt.tpe == core.Type.TBottom =>
-      Invoke(transform(callee), method, vargs.map(transform), bargs.map(transform), MetaCont(ks), Continuation.Empty)
+      Invoke(transform(callee), method, vargs.map(transform), bargs.map(transform), MetaCont(ks), Cont.Abort)
 
     case core.Stmt.Invoke(callee, method, tpe, targs, vargs, bargs) =>
       Invoke(transform(callee), method, vargs.map(transform), bargs.map(transform), MetaCont(ks), k.reify)
@@ -123,7 +123,7 @@ object Transformer {
         transform(body, ks2, Continuation.Dynamic(k2)))
 
       // if the answer type is Nothing, then the continuation is discarded anyways...
-      val continuation = if (stmt.tpe == core.Type.TBottom) Continuation.Empty else k.reify
+      val continuation = if (stmt.tpe == core.Type.TBottom) Cont.Abort else k.reify
 
       Shift(prompt.id, translatedBody, MetaCont(ks), continuation)
 
@@ -239,10 +239,4 @@ enum Continuation {
 }
 object Continuation {
   def Static(hint: Id)(k: (Pure, Id) => Stmt): Continuation.Static = Continuation.Static(hint, k)
-
-  val Empty: Cont = {
-    val a = Id("a")
-    val ks = Id("ks")
-    cps.Cont.ContLam(a, ks, cps.Hole())
-  }
 }
diff --git a/effekt/shared/src/main/scala/effekt/cps/Tree.scala b/effekt/shared/src/main/scala/effekt/cps/Tree.scala
@@ -146,6 +146,7 @@ case class Clause(vparams: List[Id], body: Stmt) extends Tree
 enum Cont extends Tree {
   case ContVar(id: Id)
   case ContLam(result: Id, ks: Id, body: Stmt)
+  case Abort
 }
 
 case class MetaCont(id: Id) extends Tree
@@ -229,6 +230,7 @@ object Variables {
   def free(ks: MetaCont): Variables = meta(ks.id)
   def free(k: Cont): Variables = k match {
     case Cont.ContVar(id) => cont(id)
+    case Cont.Abort => Set()
     case Cont.ContLam(result, ks, body) => free(body) -- value(result) -- meta(ks)
   }
 }
@@ -385,6 +387,7 @@ object substitutions {
     case Cont.ContVar(id) if subst.conts.isDefinedAt(id) => subst.conts(id)
     case Cont.ContVar(id) => Cont.ContVar(id)
     case lam @ Cont.ContLam(result, ks, body) => substitute(lam)
+    case Cont.Abort => Cont.Abort
   }
 
   def substitute(k: Cont.ContLam)(using subst: Substitution): Cont.ContLam = k match {

diff --git a/effekt/shared/src/main/scala/effekt/generator/js/TransformerCps.scala b/effekt/shared/src/main/scala/effekt/generator/js/TransformerCps.scala
@@ -182,6 +182,7 @@ object TransformerCps extends Transformer {
       nameRef(id)
     case Cont.ContLam(result, ks, body) =>
       js.Lambda(List(nameDef(result), nameDef(ks)), toJS(body)(using nonrecursive(ks)).stmts)
+    case Cont.Abort => js.Undefined
   }
 
   def toJS(e: cps.Expr)(using D: TransformerContext): js.Expr = e match {