Has anyone developed a typeclass model for (Control.Monad.mapM) and related  functions for arrows? <div><br></div><div>I&#39;ve a preliminary model, using Adam Megacz&#39;s Generalized Arrows, of the form:</div><div><br></div>
<div>class (GArrowDrop a (**) u) =&gt; GArrowMap_ a (**) u c where</div><div>   mapA_ :: a d u -&gt; a (c d) u</div><div><br></div><div>class (GArrow a (**) u c) =&gt; GArrowMap a (**) u c where</div><div>   mapA :: a d r -&gt; a (c d) (c r)</div>
<div><br></div><div>class (GArrowMap a (**) u c) =&gt; GArrowJoin a (**) u c where</div><div>   join :: a d (c r) -&gt; a (c d) (c r)</div><div><br></div><div>class (GArrow a (**) u) =&gt; GArrowUnion a (**) u c where</div>
<div>   union :: a ((c r) ** (c r)) (c r)</div><div><br></div><div>class (GArrowMap a (**) u c, GArrow a (++) v) =&gt; GArrowPartition a (**) u (++) v c where</div><div>   partition :: a d (q ++ r) -&gt; a (c d) ((c q) ** (c r))</div>
<div><br></div><div>Motivations: regular arrows (including GArrows) expose simple products for behavior, but those have a static &#39;width&#39; and don&#39;t seem suitable for processing large values. ArrowApply would give me a dynamic amount of processing, but seems excessively expressive. In my own case, &#39;c&#39; might be representing an asynchronous or distributed, reactive collection, so the ability to restrict expressiveness is important for performance. </div>
<div><br></div><div>I&#39;m wondering if you know of any other work along the same lines. </div><div><br></div><div>Thank you,</div><div><br></div><div>Dave</div>