Re: garbage collection

[Fergus Henderson]

On 17-Feb-2004, Mike Maxwell <address@hidden> wrote:
> Gregory Bourassa wrote:
> > Prolog is generally stack-oriented, so a garbage collecter
> > usually makes sense only for the global heap area, if any.
> 
> Thanks for the comments--I looked up "heap" in the index of The Craft of
> Prolog.  There are two references, one of which (p 148) doesn't seem to
> pertain, and for the other of which (p 74) I can't seem to find the word on
> the page.  Must need new reading glasses...  So I'm unclear under what
> circumstances you use the heap, although I gather it's used for compound
> terms.

Right.  In Prolog, the "heap" is also known as the "global stack".

> As for I/O, I'll actually be ripping out the original and replacing it with
> my own code.  As it happens, the input to the parser comes tokenized, with
> one word per line.  So I'm thinking of something like the following (not
> tested yet):
> 
> run :-
>     repeat,
>     readline(Wordform),
>     process(Wordform),
>     fail.
> 
> process(eof) :-
>     halt.
> process(Wordform) :-
>     parse(Wordform, Parses),
>     display(Parses).
> 
> If I'm understanding you correctly, it looks like it will backtrack past the
> readline every time it finishes a word, so the heap should be reclaimed at
> that point, correct?

Yes.

-- 
Fergus Henderson <address@hidden>  |  "I have always known that the pursuit
The University of Melbourne         |  of excellence is a lethal habit"
WWW: <http://www.cs.mu.oz.au/~fjh>  |     -- the last words of T. S. Garp.