RE: [Axiom-developer] Re: noweb

[Page, Bill]

On Thursday, May 04, 2006 4:54 AM Gabriel Dos Reis wrote:
> 
> Ralf Hemmecke writes:
> 
> | 
> | Look at this...
> | 
http://lists.gnu.org/archive/html/axiom-developer/2005-12/msg00262.html
> 
> Many thanks.
> Obviously, there have been many talks about this noweb thingy.
> I just don't understand why it lingers for so long.

Only because no one has taken the job of preparing and submitting
a patch to Tim that he will accept. Obviously I could write this
patch or even Tim could write this patch but that would not solve
the real problem that we do not have enough developer resources.
I would much rather spend a lot of time (repeatedly :) explaining
this problem in as much detail as necessary in the hopes that we
will eventually find someone (or even several people!) who are
willing to work on this problem as a way of "getting their feet
wet" (i.e. learning to do some simple axiom development). I think
Gaby's "Silver Branch" is the first time we have had a real
opportunity to correct the problem of not enough axiom developers.

Thank you Gaby!

> 
> | I would even say: Throw away the noweb sources, throw away
> | this awk script and rather go to the Axiom sources and correct
> | a usage of an undefined chunk. Why would one want to have
> | undefined chunks in the first place?
> 
> If people agree that the undefined chunks are bugs, then this
> whole noweb stuff is an unfortunate mystifying coverup.
> 

If you read the above email carefully and actually try both
Tim modified noweb and Norman Ramsey's patch you will see that
this is *not* simply a problem of an undefined chunk. The
problem is a collision of syntax that causes noweb to think
that something is a chunk plus an escape mechanism that does
not allow one to conveniently override this behavior.

In the file '  src/interp/fnewmeta.lisp.pamphlet' the text:

  <<' Name '>>

is not really a reference to a chunk but noweb thinks it is
and the standard (designed in) behavior of noweb when it
finds such an "undefined chunk" is simply to omit it. This
breaks the Axiom code.

Of course would could define this as a chunk using the noweb
escape sequence @<<

  <<' Name '>>=
  @<<' Name '>>
  @  

and solve this one case where it is really a problem (or even
use the escape sequence inline).

http://tex.loria.fr/litte/ieee.pdf

But this solution seems rather unnatural.

Tim's modification and Norman Ramsey's filter script both
change noweb's standard behavior so that if a chunk is
"undefined" then it simply passes the text of the apparent
reference straight through notangle unmodified.

The point of the filter script is to avoid the need to
include noweb source in the Axiom tree but to accomplish
the same thing as Tim's original patch.

Regards,
Bill Page.