🚀 go-pugleaf

In <849@etive.ed.ac.uk> jha@lfcs.ed.ac.uk (Jamie Andrews) writes many
things that I agree to fully. I would just like to clarify the point I made
about intension since others have asked about it also. The only point I
really wanted to make was to point out the vagueness of the notion of
"declarative language", which is used more and more often these days.

J.A. writes:
>>My view: "(declarative programming <-> programming without added intension)"
>
>     I'm not sure what you mean by "added intension".  Do you mean
>implementation considerations that make the program do more or less
>than it would seem to from a purely declarative reading?

No, what I mean by "added intension" is the possible lack of
correspondence between the intension I have about the meaning
of the program and the meaning as expressed by the "purely declarative 
reading" (Btw: Is there an "unpurely" declarative reading ?) of
the program I write. 

In program transformation (manual or mechanical) this shows up in
various situations. One of them is involved in exchange of
representational terms in logic programs, like in the introduction of
diff-structures.  The ideal is that we should be able to use strictly
logical considerations in the transformations, but it often turns out
that operational invariants must be used to guide the transformation
algorithm.

So even if there is a nice completeness result for SLD-resolution we
cannot use it for anything real, it seems, or am I too pessimistic ?


 


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Thomas Sj|land
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