Thanks Alex, I'll try it out this weekend!
On Fri, Jan 8, 2010 at 2:30 PM, Alexander Burger <a...@software-lab.de>wrote: > Hi Henrik, > > > I've just reviewed > > http://www.mail-archive.com/picolisp@software-lab.de/msg00097.html again > in > > order to move a word index to a separate database file that I want to > access > > through the remote/ext mechanism. I know some of the below has been > > That post was a little problematical, as it - as we discussed here (or > was it in IRC?) recently - contained some errors, most notably the usage > of the undefined variable 'P'. > > Anyway, after that, I corrected and extended the reference > documentation, so that I believe that it is now the most accurate and > up-to-date explanation of the matter. > > (doc '*Ext) > (doc 'remote/2) > > Especially 'remote/2' contains an extensive example. (tested here :) > > The critical part is what is the 'rsrc' function in that example. It > must provide a list of cons pairs, each with an "out" and an "in" > function. For now, I would recommend just to use that function, but for > a production application more robustness is needed, to handle closing or > failed connections. > > > > I've always had a hard time translating examples using ? into something I > > can use, how would I first do in this case: > > > > (solve > > (quote @Str Str > > (select (@Feeds) > > ((title +Feed @Str)) > > (part @Str @Feeds title))) > > @Feeds ) > > > > If we pretend that the @Feeds were located in a remote DB and the Str > comes > > from a form field in the local process? > > The above (local) 'solve' looks all right. However, just as a side note, > if only a single index (here 'title') is searched, you don't need the > full machinery of 'select', and a simple 'db' should do: > > (solve > (quote > @Str Str > (db title +Feed @Str @Feeds) ) > @Feeds ) > > Assuming the above 'rsrc' and '*Ext' from the reference, the > corresponding remote access would be > > (solve > (quote > @Str Str > @Rsrc (rsrc) > (remote (@Feeds . @Rsrc) > (db title +Feed @Str @Feeds) ) ) > @Feeds ) > > That is, you just embed the normal Pilog query into a 'remote' call. > > With 'select' it would be > > (solve > (quote > @Str Str > @Rsrc (rsrc) > (remote (@Feeds . @Rsrc) > (select (@Feeds) > ((title +Feed @Str)) > (part @Str @Feeds title) ) ) ) > @Feeds ) > > > > (collect 'word '+WordCount W W 'article) > > > > What would the above have to look like if the +WordCounts are located > > remotely? > > You mean, without using Pilog? Then you can also send the executable > s-expr directly. I'll try it here with the 'app' demo: > > : (setq Sock (connect "localhost" 4040)) > -> 17 > : (out Sock (pr (list 'collect ''nr ''+Item 2 5 ''nr))) > -> (collect 'nr '+Item 2 5 'nr) > : (in Sock (rd)) > -> (2 3 4 5) > > > > really applicable, a simple custom handler is better. But how do I build > it? > > The following is from the article linked to above: > > > > (task (port 4000) # Set up the object server in the background > > (when (setq Sock (accept @)) > > (unless (fork) # Child process > > (task P) > > (close P) > > As this is not correct (see above), better use the example in the > reference of '*Ext'. It is also a little bit simpler. > > > (in Sock > > (let Data (rd) > > (setArticleWords (car Data) (cdr Data)))) > > While this would work, it would tie the server to a single special > purpose. I would go with the above "standard" server, and just send the > whole command (like the 'collect' example above). > > On the local machine, let's assume that the variable 'Art' holds an > article that was received from the remote machine with one of the above > methods ('remote' query, or direct call). Then you can do > > (out Sock (pr 'setArticleWords (lit Art) "Data String")) > > The 'lit' is necessary to have the article quoted (and not evaluated) on > the remote side. > > Also, you need to read the result after each command, with > > (in Sock (rd)) > > because the server is set up in such a way that it always sends a > result. If I want to avoid that, I sometimes also set up a server task > that doesn't return anything. This has the advantage that the process > sending the command doesn't have to wait for the answer, so the > throughput is higher. > > > > On IRC we were discussing remote put> et. al. and you wrote down some > > examples, care to do it again? > > The above 'setArticleWords' might be replaced by a simple > > (out Sock (pr 'put!> (lit Art) "Data String")) > > Cheers, > - Alex > -- > UNSUBSCRIBE: mailto:picol...@software-lab.de?subject=unsubscribe >
