I am playing around with some small graph theory problems.<br>[Yeah I know there are good libraries -- as I said just playing around...]<br><br>And I need to do things like<br><br>type Vertex = Ix a =&gt; a<br>(so that a vertex can be used to index an adjacency-list-array)<br>
<br>That is to say that whenever &#39;Vertex&#39; appears in a type signature, the Ix should &#39;float&#39; out to the qualifier list<br>After a lot of nudging from the error messages  and rewriting as<br><br>type Vertex = forall a. Ix a =&gt; a<br>
and giving options<br> LANGUAGE RankNTypes, ImpredicativeTypes, LiberalTypeSynonyms<br><br>I still get all kinds of errors.  I&#39;ll report them if required. However first of all would like to know: Is this the way to go? Is this possible?<br>
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