I'm working on semantics and triples (RDF & co) Python code for inference in based totally on dictionaries (associative arrays ??),nested three or four times. The result is astonishing me:compact beautiful modular and extremely readable. I imagine that haskell way should be different but I'm in the dark. As the stream of triples coming from outside estabilishes the actions to be done for inference,the searching through keys (the words that form any triple) is the main job:every time I pick up a triple I have to enlarge the knowledge more or less "near" the resources represented by the words. And after I have produced (possibly) some new inferred triples surely I have to reswitch on some already read triples, matching a pattern. All these are very natural with dictionaries, so I'd like to figure out the haskell view. Thanks for your quiteness and answers Paolino -- ....lotta dura per la verdura