Re: Frustrations/problems with GNU Prolog.

[Daniel Diaz]

Le 11/07/2011 15:32, Steve641 a écrit :
> I'm not sure how complex these questions are... I last wrote Prolog (using
> Sicstus/SWI Prolog interpreters) in the early 1990s... I was rusty, but I
> soon rediscovered lots of useful idioms.
>
> I've a script which I can consult from the command line of gprolog, and it
> does what I want when I evaluate a predicate main/0.  I'm having some
> difficulties packaging my solution....  I'd like users to be blissfully
> unaware that they're using a Prolog solution when they invoke it by name
> from a shell prompt.
>
> The environment I'm using is Linux - the current Ubuntu Server distribution
> for a 64-bit AMD system.
>
> $ uname -a
> Linux server 2.6.38-8-generic #42-Ubuntu SMP Mon Apr 11 03:31:24 UTC 2011
> x86_64 x86_64 x86_64 GNU/Linux
> $
>
> I've installed the GNU prolog package (version 1.3.0 is the one in the
> current Ubuntu Universe) and it's details are:
>
> $ apt-cache showpkg gprolog
> Package: gprolog
> Versions:
> 1.3.0-6.1
> (/var/lib/apt/lists/gb.archive.ubuntu.com_ubuntu_dists_natty_universe_binary-amd64_Packages)
> (/var/lib/dpkg/status)
>   Description Language:
>                   File:
> /var/lib/apt/lists/gb.archive.ubuntu.com_ubuntu_dists_natty_universe_binary-amd64_Packages
>                    MD5: bda800d61124d7f1de09fc061fac1d22
> Reverse Depends:
>    science-machine-learning,gprolog
>    prolog-el,gprolog
>    mace2,gprolog
>    laby,gprolog
>    laby,gprolog
>    gprolog-doc,gprolog 1.2.7
> Dependencies:
> 1.3.0-6.1 - libc6 (2 2.11) gprolog-doc (0 (null))
> Provides:
> 1.3.0-6.1 -
> Reverse Provides:
> $
>
> When I try to compile my script to native, using glpc, I get unexpected
> results.
>
> First, for any script, I get two (worrying-looking) warnings:
>
> $ gplc trivial.pl
> /usr/bin/ld: Warning: alignment 8 of symbol `init_stream_supp' in
> /usr/lib/gprolog-iso/libbips_pl.a(stream_supp.o) is smaller than 16 in
> /usr/lib/gprolog-iso/libengine_pl.a(engine.o)
> /usr/bin/ld: Warning: alignment 8 of symbol `fd_reset_solver' in
> /usr/lib/gprolog-iso/libengine_fd.a(fd_inst.o) is smaller than 16 in
> /usr/lib/gprolog-iso/libengine_pl.a(if_no_fd.o)
> $
>
> At first glance, these seem to be a problem with the Ubuntu packages for my
> architecture.  Is this a known problem?  Are there any quick/easy
> work-arounds?  (I'd like a clean compile.)
This is due to a gcc bug. This should not prevent gprolog from working.

If you want a clean compile, get the last version.

http://gprolog.org/gprolog-1.4.0.tar.gz

You will have to compile and install it by yourself (until a ubuntu 
package is available). Follow the INSTALL file for this.

Basically,

cd src
./configure
make
make install

> Next, for my script, I get a series of frustrating errors - all of this
> form:
>
> /tmp/gplcUheTSf.o: In function `predicate(isValid/2)':
> (.text+0x1ad): undefined reference to `predicate(validRanges/2)'
>
> Subsequent errors have a different location in .text - of course.  In one
> sense, this should not surprise me as there is no explicit definition for
> validRanges/2 in my source code.  My strategy was to require user input of
> the desired ranges - then use asserta/1 to establish validRanges as a fact
> before evaluating any predicate that needed it.  This works fine from the
> interactive prompt - but not when compiling to native.
You have to inform the compiler validRanges/2 is a dynamic predicate. 
Add the following directive to your Prolog file:

:- dynamic(validRanges/2).

See: http://gprolog.org/manual/html_node/gprolog022.html#toc29
> be to pass the ranges recursively and explicitly to every predicate that
> needs them... but this seems ugly.  Are there any alternative strategies to
> overcome this?
>
> Finally, I'm wondering if there is any support for passing command line
> arguments to executables implemented using GNU prolog?  In an ideal world,
> I'd pass the desired ranges as command line arguments rather than require
> them to be entered interactively.  Any hints gratefully received.
You can look at the following built-in predicates: argument_counter, 
argument_value, argument_list

http://gprolog.org/manual/html_node/gprolog051.html#toc201

Daniel


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