Re: Help on disassembler/decompilers

In article <679@culhua.prg.ox.ac.uk> Jonathan Bowen <Jonathan.Bowen@prg.oxford.ac.uk> writes:
>produce a high-level program or programs as output. The main problem is
>running the necessary arithmetic backwards (i.e. avoiding the use of
>"is") and I am currently looking into this. Has anyone else done any
>similar work or can anyone supply any useful references?


Funny, I didn't _see_ this in comp.lang.prolog...


To answer your query, arithmetic _can_ be run backward.


One simple, but inefficient, technique is to use ``unary'' arithmetic. (I.e.
zero is 0, 1 is suc(0), 2 is suc(suc(0))). Rewriting the is/2, >/2, etc is a
pain but it _can_ be done.


Quite a lot of interesting work has been done on investigating which Prolog
relations can run backward -- look thru the Int Conf on Logic Prog & similar
things (they only go a few years so why check out the ref for you)?


DHD Warren wrote a nice article in Software Practice and Experience regarding
compiler-writing in Prolog -- check that out too (he writes fairly _neat_
code for one thing, and we're talking about readability here).


-Kym Horsell
--

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