Transput RFC - early version based on POSIX

[Pietro Monteiro]

On Thu, May 21, 2026, at 1:39 PM, chris hermansen wrote:
> Good morning everyone,
>
> Jose, thanks for the comments you provided.  One more question below:
> On Thu, May 21, 2026 at 2:16 AM Jose E. Marchesi <jemarch@gnu.org> wrote:
>> 
>> Hello Chris.
>> 
>> > Good afternoon everyone,
>> >
>> > After monkeying around far too long trying to pull out bits of van
>> > Vliet's transput so I could implement it piece by piece, I have given up on
>> > that approach (way too many dependencies between things in there) and am
>> > gritting my teeth and starting back at the beginning.
>> >
>> > To facilitate getting as much as possible working, I'd like to put van
>> > Vliet's code and ideas on top of Algol 68 POSIX for now, forgetting about
>> > reading and writing binary for the first go-around.
>> >
>> > Does that make sense?
>> 
>> To me, it makes 100% sense.  In my experience, once you get something
>> working it becomes easier to reason about it.  There is a lot to learn
>> in the process too.
>> 
>> > Assuming it's not too crazy an idea, the first bump on the road I've
>> > encountered is dealing with system file status.  As far as I can tell, the
>> > only pathway in Algol 68 POSIX for this type of thing is to call fopen() or
>> > fcreate() with various flags as documented here:
>> >
>> > https://gcc.gnu.org/onlinedocs/ga68/POSIX-files.html
>> >
>> > and then, based on what works and what doesn't, I can resolve many of van
>> > Vliet's "possibles":
>> > - get_possible(f) { true if fopen(filename, bits file o rdonly) returns ≥ 0
>> > }
>> > - put_possible(f) { true if fopen(filename, bits file o wronly) returns ≥ 0
>> > }
>> > - bin_possible(f) { always false for now }
>> > - compressible(f) { always true - indicates variable length lines }
>> > - reset_possible(f) { always true for now }
>> > - set_possible(f) { always true for now because lseek() }
>> > - backspace_possible(f) { always true for now because lseek() }
>> > - reidf_possible(f) { always false for now because Algol 68 transput
>> > doesn't provide rename() }
>> >
>> > Does this sound like an acceptable start?
>> 
>> I think it would be better to call to the system's fstat, a wrapper for
>> which needs to be added to the POSIX prelude.
>
> Are you suggesting here that (gasp) I add this in and create a patch?
>
> Am I too old a dog to learn a new trick?

Since Jose added support for writing libga68 preludes in Algol 68 this became much easier.
If it's an easy mapping from C you just need to add it to libga68/posix.a68.
If not, you need a add a C wrapper in libga68/ga68-posix.c and then in libga68/posix.a68.

Don't forget to add docs in gcc/algol68/ga68.texi and tests in gcc/testsuite/algol68/compile
or gcc/testsuite/algol68/execute

> -- 
> Chris Hermansen · clhermansen "at" gmail "dot" com
>
> C'est ma façon de parler.

pietro