[Gsll-devel] with-ode-integration macro problem on clisp

[Liam Healy]

Mirko,

It looks like there is a bug there in CLISP; symbol-macrolet is a part
of the standard and it should work.  I have given up on testing in
CLISP because I encounter so many errors that seem to be a problem on
their side.  If you can get a useful answer out of CLISP, that's
great, but you should switch to SBCL or CCL if you can because I do
test on these.

As to whether it should be a symbol-macro or a function call I think
it is a style issue.  I'm not terribly happy with the macro as it is,
I think it requires rethinking anyway, I just hacked through it to get
something out that would get rid of the with-c-double.  I'll return to
it at some point but I have other things I'm working on first.

Liam

On Sat, Jan 31, 2009 at 7:06 PM, Mirko Vukovic <mirko.vukovic at gmail.com> wrote:
> Liam,
>
> The file `ode-example.lisp' could not compile on clisp+cygwin+windows.
>  The error occurred in `integrate-vanderpol', which uses the
> `with-ode-integration' macro.
>
> I traced the problem to the symbol-macrolet generated macro
> `make-next-step'.  It looks like the loop body cannot digest symbols
> created with symbol-macrolet (again clisp only, not sbcl).
>
> I was able to fix the problem by changing make-next-step into a
> function via labels.
>
> I am attaching a file that illustrates the problem, fix and
> verification.  It has has several items:
> 1) illustration with a simple code on where clisp fails when loop uses
> a symbol-macrolet based symbol
> 2) the modified with-ode-integration macro
> 3) a version of integrate-vanderpol based on the modified macro
> 4) an example of a test-suite where I compared the outputs of your
> macro with the modified macro, using your examples of integrating
> vanderpol.
>
> This issue is not a major show-stopper for me, since I have a working
> version now.  I can see why make-next-step should be defined as a
> symbol-macro -- it is so simple.  On the other hand, strictly
> visually, its appearance as a symbol in the body of the loop between
> two forms is a bit jarring.  Also, make-next-step is an `internal'
> symbol to the with-ode-integration macro, and maybe should not be
> visible to the user.
>
> But all of the above are really, minor, minor points, because the user
> is free to write their own version of `with-ode-integration' :-)  The
> major point is really that sooner or later someone else will try to
> compile on clisp and hit the same problem.
>
> Mirko
>
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