29 Mar
                
                    2009
                
            
            
                29 Mar
                
                '09
                
            
            
            
        
    
                10:28 p.m.
            
        Nested constructed product returns? Or constructed sums? lennart:
Well, yes and no. GHC actually does a decent job when given very imperative code with references and mutable arrays. Now the type I use to wrap the references to get type safe l-values and r-values makes it tricker, and ghc lacks a crucial optimization for specialization of constructor returns. With that in place I think the code could be quite performant.