🚀 go-pugleaf

In article <3923@okstate.UUCP> norman@a.cs.okstate.edu (Norman Graham) writes:

>in as well.  Logic languages only seem to provide syntatic sugar
>for a handful of functions easily written in the above language.
>|-: Don't flame me for that last statement.  If it's incorrect
>just write it off as a statement by a logic programming novice and
>explain why it ain't so. :-| 


Logic is not merely syntactic sugar on top of functions.  First, unification
is much more general then function invocation, for obvious reasons.  This
gives logic added expressive power.  Second, a logic predicate is reversible
(i.e. it can be "solved" for any combination of arguments bound), while 
functions have prespecified input and output arguments.  Again, this adds
expressive power since in the worst case you would need 2^n functions for
each logic predicate where there are a total of n inputs and outputs.
 
Finally (although I'm sure there are other reasons around), the nature of 
the logical variable is more amenable to lazy evaluation and other such
niceties.  

Now, if you were to say that functions only provide syntactic sugar for a
handful of predicates written in logic languages, I would probably agree :-)