unification

[David Feuer]

> From: Thomas Hallgren <hallgren@cse.ogi.edu>
> David Feuer wrote:
> 
> >Has anyone written an efficient purely-functional 
> >implementation of unification (for type checking)?
> >
> Well, if you have ever used hbc or nhc, you have used 
type checkers 
> containing purely functional implementations of 
unification. Purely 
> functional unification can be efficient enough for 
practical purposes...


Thank you for this information.  However, it does not 
quite satisfy my curiosity:  are these purely functional 
type checkers as efficient (big-O) as imperative ones?  
And if not, why not?

David Feuer

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