more direct implementation of async map

Author: rouzwawi

cli/src/main/java/io/rouz/task/cli/TaskConstructor.java

@@ -1,7 +1,6 @@
 package io.rouz.task.cli;
 
 import io.rouz.task.Task;
-
 import joptsimple.OptionParser;
 
 /**

workflow/src/main/java/io/rouz/task/TaskBuilders.java

@@ -335,7 +335,7 @@ private static final class ChainingEval<F> implements Serializable {
 
     public <Z> EvalClosure<Z> enclose(F f) {
       //noinspection unchecked
-      return tc -> (Value<Z>) fClosure.apply(tc).apply(f);
+      return taskContext -> (Value<Z>) fClosure.apply(taskContext).apply(f);
     }
 
     public <G> ChainingEval<G> chain(F1<TaskContext, F1<G, Value<F>>> mapClosure) {

workflow/src/main/java/io/rouz/task/context/AsyncContext.java

@@ -80,6 +80,11 @@ public void consume(Consumer<T> consumer) {
       future.thenAccept(consumer);
     }
 
+    @Override
+    public <U> Value<U> map(Function<? super T, ? extends U> fn) {
+      return new FutureValue<>(future.thenApply(fn));
+    }
+
     @Override
     public <U> Value<U> flatMap(Function<? super T, ? extends Value<? extends U>> function) {
       return flatten(future.thenApply(function));