Café,<br><br>I&#39;ve tried several things already, but I am not including any of them for now.<br>My question is, how would you define the &#39;transform&#39; function for a GADT, say the one in the linked gist: <a href="http://gist.github.com/492364">http://gist.github.com/492364</a> (also attached to this e-mail)<br>
<br>To be concise, I want &#39;transform&#39; to apply the transformation function (its first parameter) to every immidiate child of its second parameter as long as the types match. Similar to what the &#39;tranform&#39; function of Uniplate does for normal ADTs. (But just one level, so I guess it is more similar to the &#39;descend&#39; of Uniplate. See <a href="http://hackage.haskell.org/packages/archive/uniplate/1.2.0.1/doc/html/Data-Generics-UniplateStr.html">http://hackage.haskell.org/packages/archive/uniplate/1.2.0.1/doc/html/Data-Generics-UniplateStr.html</a>)<br>
<br>I think I got closest to a sensible solution using multi-param type classes, and defining many instances for different combinations of ExprType&#39;s but still there were problems.<br><br>Waiting for suggestions and/or insights.<br>
<br>Best,<br>Ozgur Akgun<br>