Error: ~~:@> not implemented

[Matthew K. <mke...@ge...>]

I noticed a problem when CLISP 2.32 is used to load ASDF (asdf.lisp
to be specific).  An example from  asdf.lisp is this:

[1]> (format nil "~@<erred while invoking ~A on ~A~@:>" "asd"
"asdasd")

*** - ~<...~:> not implemented yet
Current point in control string:
  ~@<erred while invoking ~A on ~A~@:>
  |
Break 1 [2]>

Previously, CLISP 2.31 didn't cause an error when encountering such
control strings.

I made an attempt at patching ASDF[1].  Of course it works, but what
I needed to do was tedious (add a lot of #-clisp and #+clisp and
strip out the logical-block stuff).  A quick scan of the dozen or so
other Common Lisp sources I have installed on my system reveal a
few other sources make use of the logical-block stuff, but this is
only a subset of what is available.

(As a documentation aside, I don't think this behavior is mentioned in
the implementation notes.)

I'm looking for advice on better ways to handle such code under CLISP
2.32.  I have been thinking about patching src/format.lisp to issue a
warning rather than an error.  

Matt

Footnotes: 
[1]  http://dev.gentoo.org/~mkennedy/asdf.lisp-1.78-clisp-2.32-format-logical-block.patch

-- 
Matthew Kennedy
Gentoo GNU/Linux Developer