New Scalaz operator ~~>? which is ~~> but for optional callbacks.

Closes #58

Author: japgolly

doc/CHANGELOG-0.7.md

@@ -10,6 +10,7 @@ https://gist.github.com/japgolly/c68482dbadb0077f550c
 * Added a `ext-monocle` module with a few extensions for [Monocle](https://github.com/julien-truffaut/Monocle).
 * More supported React tags and attributes.
 * More ScalazReact extensions: `{state,setState,modState,modStateF}IO`.
+* New Scalaz operator `~~>?` which is `~~>` but for optional callbacks.
 * Removed deprecated methods marked for removal in 0.7.0.
 * Deprecated `modStateO` and `modStateU`.
 

scalaz-7.0/src/main/scala/japgolly/scalajs/react/ScalazReact.scala

@@ -1,7 +1,7 @@
 package japgolly.scalajs.react
 
 import org.scalajs.dom
-import japgolly.scalajs.react.vdom.Attr
+import japgolly.scalajs.react.vdom.{TagMod, Attr, Optional, EmptyTag}
 import japgolly.scalajs.react.vdom.Implicits._
 import scala.scalajs.js.{UndefOr, undefined}
 import scalaz._
@@ -20,11 +20,18 @@ object ScalazReact {
 
   @inline implicit final class SzRExt_Attr(val _a: Attr) extends AnyVal {
 
-    def ~~>(io: => IO[Unit]) =
+    @inline final def ~~>(io: => IO[Unit]): TagMod =
       _a --> io.unsafePerformIO()
 
-    def ~~>[N <: dom.Node, E <: SyntheticEvent[N]](eventHandler: E => IO[Unit]) =
+    @inline final def ~~>[N <: dom.Node, E <: SyntheticEvent[N]](eventHandler: E => IO[Unit]): TagMod =
       _a.==>[N, E](eventHandler(_).unsafePerformIO())
+
+    @inline final def ~~>?[T[_]](t: => T[IO[Unit]])(implicit o: Optional[T]): TagMod =
+      _a --> o.foreach(t)(_.unsafePerformIO()) // This implementation keeps the argument lazy
+      //o.fold[IO[Unit], TagMod](t, ~~>(_), EmptyTag)
+
+    @inline final def ~~>?[T[_], N <: dom.Node, E <: SyntheticEvent[N]](eventHandler: E => T[IO[Unit]])(implicit o: Optional[T]): TagMod =
+      _a.==>[N, E](e => o.foreach(eventHandler(e))(_.unsafePerformIO()))
   }
 
   @inline implicit final class SzRExt_C_M(val _c: ComponentScope_M[_]) extends AnyVal {

scalaz-7.1/src/main/scala/japgolly/scalajs/react/ScalazReact.scala

@@ -1,17 +1,17 @@
 package japgolly.scalajs.react
 
 import org.scalajs.dom
-import japgolly.scalajs.react.vdom.Attr
+import japgolly.scalajs.react.vdom.{TagMod, Attr, Optional, EmptyTag}
 import japgolly.scalajs.react.vdom.Implicits._
 import scala.scalajs.js.{UndefOr, undefined}
-import scalaz._
+import scalaz.{Optional => _, _}
 import scalaz.effect.IO
 import Scalaz.Id
 import Leibniz.===
 
 object ScalazReact {
 
-  implicit object OptionalMaybe extends vdom.Optional[Maybe] {
+  implicit object OptionalMaybe extends Optional[Maybe] {
     @inline final override def foreach[A](m: Maybe[A])(f: (A) => Unit): Unit = m.cata(f, ())
     @inline final override def fold[A, B](t: Maybe[A], f: A => B, b: => B): B = t.cata(f, b)
   }
@@ -23,11 +23,18 @@ object ScalazReact {
 
   @inline implicit final class SzRExt_Attr(val _a: Attr) extends AnyVal {
 
-    def ~~>(io: => IO[Unit]) =
+    @inline final def ~~>(io: => IO[Unit]): TagMod =
       _a --> io.unsafePerformIO()
 
-    def ~~>[N <: dom.Node, E <: SyntheticEvent[N]](eventHandler: E => IO[Unit]) =
+    @inline final def ~~>[N <: dom.Node, E <: SyntheticEvent[N]](eventHandler: E => IO[Unit]): TagMod =
       _a.==>[N, E](eventHandler(_).unsafePerformIO())
+
+    @inline final def ~~>?[T[_]](t: => T[IO[Unit]])(implicit o: Optional[T]): TagMod =
+      _a --> o.foreach(t)(_.unsafePerformIO()) // This implementation keeps the argument lazy
+      //o.fold[IO[Unit], TagMod](t, ~~>(_), EmptyTag)
+
+    @inline final def ~~>?[T[_], N <: dom.Node, E <: SyntheticEvent[N]](eventHandler: E => T[IO[Unit]])(implicit o: Optional[T]): TagMod =
+      _a.==>[N, E](e => o.foreach(eventHandler(e))(_.unsafePerformIO()))
   }
 
   @inline implicit final class SzRExt_C_M(val _c: ComponentScope_M[_]) extends AnyVal {

sync-scala70

@@ -6,7 +6,10 @@ s1=scalaz-7.1
 
 f=src/main/scala/japgolly/scalajs/react/ScalazReact.scala
 echo "$f"
-perl -pe 's!(?<=[^A-Z_]M\[)_!+_!' < $s1/$f > $s0/$f
+perl -pe '
+  s!(?<=[^A-Z_]M\[)_!+_!;
+  s/{Optional => _, _}/_/;
+  ' < $s1/$f > $s0/$f
 sed -i "
   /OptionalMaybe/,/^ *} *$/d;
   /^object/a\  // Don't edit this directly. Run $(basename "$0")