Merge pull request #126 from kategory/paco-readerfix

Fix first Reader implicit instantiation

Author: ffgiraldez

kategory/src/main/kotlin/kategory/data/Reader.kt

@@ -7,20 +7,20 @@ infix fun <A, B, C> ((A) -> B).andThen(g: (B) -> C): (A) -> C =
         { a: A -> g(this(a)) }
 
 fun <D, A> ((D) -> A).reader(): ReaderT<Id.F, D, A> =
-        Reader(this)
+        Reader(this, Id)
 
 fun <D, A> ReaderT<Id.F, D, A>.runId(d: D): A =
         this.run(d).value()
 
 object Reader {
 
-    operator fun <D, A> invoke(run: (D) -> A): ReaderT<Id.F, D, A> =
-            Kleisli(run.andThen { Id(it) })
+    operator fun <D, A> invoke(run: (D) -> A, MF: Monad<Id.F> = Id): ReaderT<Id.F, D, A> =
+            Kleisli(run.andThen { Id(it) }, MF)
 
-    fun <D, A> pure(x: A): ReaderT<Id.F, D, A> =
-            Kleisli.pure<Id.F, D, A>(x)
+    fun <D, A> pure(x: A, MF: Monad<Id.F> = Id): ReaderT<Id.F, D, A> =
+            Kleisli.pure<Id.F, D, A>(x, Id)
 
-    fun <D> ask(): ReaderT<Id.F, D, D> =
-            Kleisli.ask<Id.F, D>()
+    fun <D> ask(MF: Monad<Id.F> = Id): ReaderT<Id.F, D, D> =
+            Kleisli.ask<Id.F, D>(Id)
 
 }

kategory/src/test/kotlin/kategory/data/ReaderTest.kt

@@ -8,7 +8,7 @@ import org.junit.runner.RunWith
 class ReaderTest : UnitSpec() {
     init {
         "map should return mapped value" {
-            Reader<Int, Int> { it -> it * 2 }.map { it -> it * 3 }.runId(2) shouldBe 12
+            Reader<Int, Int> ({ it -> it * 2 }).map { it -> it * 3 }.runId(2) shouldBe 12
         }
 
         "flatMap should map over the inner value" {