[Openmcl-devel] Using OpenMCL as a shell scripting interpreter

[Gary Byers]

On Sun, 28 Mar 2004, Stonewall Ballard wrote:

> I haven't had much time to work on this, so I'd appreciate any help I
> can get.
>
> Aside from replicating some of my Python utility scripts in Lisp to see
> whether I feel comfortable with using it that way, my other problem is
> how to coerce openmcl to run from a simple text file. I'm not going to
> make a megabyte image for every script - I need to keep them as text
> until they're run, just like other shell languages.
>
> I've tried invoking openmcl with a #! first line in a file, and while
> openmcl apparently runs, it doesn't go anywhere. I would have thought
> that:
>
> #!/usr/local/bin/openmcl -V
>
> would print the version number, but I can't find the output anywhere.

I don't see any evidence that the shell script is even invoked in this
case.

If you change the first line to refer to the executable and save that
in a text file called "showversion", as in:

#!/usr/local/src/ccl/dppccl -V

the executable will be invoked as

argv[0] = "dppccl" (not "/usr/local/src/ccl/dppccl")
argv[1] = "-V"
argv[2] = "showversion"

dppccl expects (naively) to have been invoked with its own full pathname,
and uses that to find the default image name.

To get that to work, I think that we'd have to

(a)  use some other technique to find the executable's own pathname
    and derive the default image name from it.

(b) change the command-line parsing so that the script name has some
    meaning.  (Currently, a random file name - not preceded by "--load"
    or "--eval"  or something - isn't interpreted sensibly.)

You could almost get (b) to work by doing something like

#!/usr/local/src/ccl/dppccl --load

though of course loading such a file would complain that the reader
macro #! is undefined.  (I suppose that you could make #! behave as
; does.)

As far as (a) goes: I know how to do this under Linux; on Darwin, I
can't think of a way to do this without doing what "ps" does, which
many involve the use of things that Apple considers "unstable".  I may
be forgetting something obvious; does anyone know of a "stable" way to
obtain the full pathname of the current process's executable under
Darwin ?