Remove Scope in favor of simple (A=>R)=>R

ThoughtWorksInc · Feb 28, 2018 · 4161b44 · 4161b44
1 parent 587ab79
commit 4161b44
Show file tree

Hide file tree

Showing 5 changed files with 20 additions and 81 deletions.
diff --git a/Dsl/src/main/scala/com/thoughtworks/dsl/Dsl.scala b/Dsl/src/main/scala/com/thoughtworks/dsl/Dsl.scala
@@ -1,9 +1,6 @@
 package com.thoughtworks.dsl
 
-import com.thoughtworks.dsl.Dsl.shift
-
 import scala.annotation.{Annotation, StaticAnnotation, TypeConstraint, compileTimeOnly}
-import scala.util.control.NonFatal
 
 /** The domain-specific interpreter for `Instruction` in `Domain`,
   * which is a dependent type type class that registers an asynchronous callback function,
@@ -21,6 +18,20 @@ trait Dsl[-Instruction, Domain, +Value] {
 
 object Dsl {
 
+  implicit def scopeDsl[Instruction, Domain, FinalResult, InstructionValue](
+      implicit restDsl: Dsl[Instruction, Domain, InstructionValue])
+    : Dsl[Instruction, (FinalResult => Domain) => Domain, InstructionValue] = {
+    new Dsl[Instruction, (FinalResult => Domain) => Domain, InstructionValue] {
+      def interpret(instruction: Instruction,
+                    handler: InstructionValue => (FinalResult => Domain) => Domain): (FinalResult => Domain) => Domain = {
+        (continue: FinalResult => Domain) =>
+          restDsl.interpret(instruction, { a =>
+            handler(a)(continue)
+          })
+      }
+    }
+  }
+
   final case class Catch[Domain](onFailure: Throwable => Domain)
       extends AnyVal
       with Instruction[Catch[Domain], Domain => Domain]

diff --git a/build.sbt b/build.sbt
@@ -18,14 +18,8 @@ lazy val `instructions-ScalazBind` =
 lazy val `instructions-CatsFlatMap` =
   project.dependsOn(Dsl, `instructions-Shift` % Test, `instructions-Yield` % Test)
 
-lazy val `domains-Scope` = project.dependsOn(Dsl)
-
 lazy val `instructions-Arm` =
-  project.dependsOn(Dsl,
-                    `domains-Scope`,
-                    `instructions-Shift`,
-                    `instructions-Yield` % Test,
-                    `domains-ExceptionHandling`)
+  project.dependsOn(Dsl, `instructions-Shift`, `instructions-Yield` % Test, `domains-ExceptionHandling`)
 
 organization in ThisBuild := "com.thoughtworks.dsl"
 

diff --git a/domains-Scope/src/main/scala/com/thoughtworks/dsl/domains/Scope.scala b/domains-Scope/src/main/scala/com/thoughtworks/dsl/domains/Scope.scala
diff --git a/instructions-Arm/src/main/scala/com/thoughtworks/dsl/instructions/Arm.scala b/instructions-Arm/src/main/scala/com/thoughtworks/dsl/instructions/Arm.scala
@@ -2,7 +2,6 @@ package com.thoughtworks.dsl.instructions
 
 import com.thoughtworks.dsl.Dsl
 import com.thoughtworks.dsl.Dsl.Instruction
-import com.thoughtworks.dsl.domains.{ExceptionHandling, Scope}
 import resource.Resource
 
 /**
@@ -32,27 +31,4 @@ object Arm {
       }
     }
 
-  implicit def armDsl[Domain, R](
-      implicit dsl: com.thoughtworks.dsl.Dsl[com.thoughtworks.dsl.Dsl.Catch[Domain], Domain, Domain => Domain])
-    : Dsl[Arm[R], Scope[Domain], R] = new Dsl[Arm[R], Scope[Domain], R] {
-    def interpret(arm: Arm[R], inUse: R => Scope[Domain]): Scope[Domain] = {
-      val resourceFactory = arm.resourceFactory
-      val resource = arm.resource
-
-      new Scope[Domain] {
-        def apply(continue: Domain => Domain): Domain = {
-          continue {
-            val r = resourceFactory()
-            try {
-              resource.open(r)
-              !Shift(inUse(r))
-            } finally {
-              resource.close(r)
-            }
-          }
-        }
-      }
-    }
-  }
-
 }
diff --git a/instructions-Arm/src/test/scala/com/thoughtworks/dsl/instructions/ArmSpec.scala b/instructions-Arm/src/test/scala/com/thoughtworks/dsl/instructions/ArmSpec.scala
@@ -1,6 +1,6 @@
 package com.thoughtworks.dsl.instructions
 
-import com.thoughtworks.dsl.domains.{ExceptionHandling, Scope}
+import com.thoughtworks.dsl.domains.ExceptionHandling
 import com.thoughtworks.dsl.instructions.Shift.Continuation
 import org.scalatest.{FreeSpec, Matchers}
 
@@ -10,28 +10,16 @@ import org.scalatest.{FreeSpec, Matchers}
 class ArmSpec extends FreeSpec with Matchers {
 
   "AutoCloseable" - {
-    //
-    //    "using" in {
-    //      var isOpen = false
-    //      def autoCloseable: Unit = {
-    //        isOpen should be(false)
-    //        !Arm(new AutoCloseable {
-    //          def close(): Unit = {
-    //            isOpen should be(true)
-    //            isOpen = false
-    //          }
-    //        })
-    //        isOpen should be(true)
-    //      }
-    //      isOpen should be(false)
-    //    }
+
+    type Scope[A] = (A => A) => A
+    def noop[A](a: A): Scope[A] = _(a)
 
     "scope" - {
 
       "arm" in {
         var isOpen = false
 
-        def raii: Scope[ExceptionHandling[Stream[Int]]] = Scope.noop {
+        def raii: Scope[ExceptionHandling[Stream[Int]]] = noop {
           ExceptionHandling.success {
             !Yield(1)
             isOpen should be(false)