[GAP Forum] Using the GAP language as an ordinary programming language

[Leonard Soicher]

Dear Forum,

On Wed, Oct 08, 2014 at 09:02:54PM -0400, Tim Kohl wrote:
> You can create GAP scripts, the convention being to call such a script 
> myprogram.g for example and
> be sure to include the command 
> 
> quit;
> 
> as the last line,
> and with this you can do something like
> 
> gap < myprogram.g 
> 
> which will allow you to see the script run ( and to see if it got stuck at an error ) or if your sure of the correctness just do
> 
> gap < myprogram.g > myprogram.out
> 
> where the .out file has the output.


This is essentially what I would do, as well as having 

LogTo("myprogram.log"); 

as the first line of  myprogram.g  
in order for  myprogram.log  to be a log-file showing the 
GAP input followed by its corresponding output, 
in the order executed. 

Leonard


> 
>     -Tim K.
> 
> Sent from my iPhone
> 
> > On Oct 8, 2014, at 7:02 PM, Douglas Wilson <douglaspardoewilson at gmail.com> wrote:
> > 
> > I've been using Python, and therefore have
> > access to Sage, which includes an interface
> > to GAP.  So I can write a Python program
> > that, via Sage, will let me evaluate an
> > expression using GAP.
> > 
> > That seems a very round-about way of
> > using GAP, and is limited to single
> > expressions.  What I'd really like to do is
> > run a GAP language program from the
> > command line.  I can pass a saved workspace
> > to GAP on the command line, which will
> > be used in the subsequent interactive session,
> > but that is not the same thing.
> > 
> > I realize that the GAP is oriented towards
> > interactive sessions in a workspace, but surely
> > there are ways around that.  For example,
> > Smalltalk used to be the same way, but
> > GNU Smalltalk will allow you to specify
> > a program from the command line, which
> > it will then run and exit.
> > 
> > One motive for asking this is straightforward.
> > For me, hi-tech means making the best use
> > of the underlying science.  Modern computer
> > hardware uses a lot of technology based on
> > physics, and is therefore hi-tech.  Almost
> > all modern computer software makes little
> > use at all of mathematics, and therefore is
> > actually quite lo-tech, however sophisticated
> > it may seem to the user.
> > 
> > The future of software, in my opinion will
> > inevitably involve more and more use of
> > mathematics.  For that purpose, there should
> > be a highly mathematical computer
> > programming language.  And behold,
> > there is: the GAP language.  Except
> > for the ability to create Graphical User
> > Interfaces, it is functionally complete
> > and can do anything more ordinary
> > languages can.  That single deficiency
> > could be remedied easily be interfacing
> > with a simple windowing system, like Tk,
> > as Python does.  I'm not much interested
> > in writing GUI programs myself, just
> > ones to work from the command line.
> > 
> > My own work is actually quite mathematical,
> > and I would like to be able to do things
> > like specifying a group by a presentation,
> > identifying it, and working with it in the
> > usual way.  But I don't want to do it
> > interactively, nor do I want to be loading
> > up saved workspaces all the time.  I just
> > want to use the GAP language like any
> > other one.
> > 
> > Perhaps this capability already exists.
> > If so, I can fine no documentation of it
> > in the reference manual.  Perhaps you
> > could point me to some.  If it doesn't
> > exist yet, could it be provided somehow?
> > 
> >     dpw
> > 
> > http://DouglasPardoeWilson.SocialTechnology.ca/
> > _______________________________________________
> > Forum mailing list
> > Forum at mail.gap-system.org
> > http://mail.gap-system.org/mailman/listinfo/forum
> 
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