[Asdf-devel] syntax-control branch

Robert P. Goldman rpgoldman at sift.info
Fri Jun 6 21:04:38 UTC 2014

Faré wrote:
> Dear Robert,
> I saw you had another question in the syntax-control.txt document,
> about what breaks if you try to work around a readtable conflict by
> somehow forcing load order. I replied in the document.
> You say that you had a system that was broken by my branch — did it
> indeed have a readtable conflict while somehow changing the readtable
> e.g. in a .asd file itself?

My large system is broken, but I have not been able to diagnose the
problem.  It is turning up *way* downstream.  I get a type error where a
class is not getting the right METACLASS.

I suspect it has to do with the fact that we have an ASDF extension that
binds *READTABLE* in a PERFORM :AROUND method, but I have not been able
to determine whether this is, in fact, the problem.

I can't imagine how anyone would guess that this error is a readtable
fail, much less that it was caused by a modification to ASDF.  This
problem will be even worse if the modification to ASDF is quietly given
to the poor programmer through an update to his or her CL implementation.

I pretty much *know* this is a readtable fail and I'm not having an easy
time figuring out what went wrong.

This is why I'm not enthusiastic about the syntax-control branch.  It's
fail-obscure, and we can't count on programmers inferring that their
code has suddenly gone pear-shaped because of a modification to ASDF,
especially if it wasn't a modification to ASDF that they installed

Let's say one day I get a new SBCL or ACL, and all of a sudden I get an
error like this.  I'm not an ASDF hacker.  I don't even know that the
new CL version has updated the bundled ASDF. How would I begin to figure
out what went wrong?

Until I have an answer to that question, I cannot merge the
syntax-control code.


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