Hi,

I'm willing to install the attached patch soon: it adds support for
SRFI-35.

Guile-Lib already contains an implementation (by Andreas Rottmann).
However, it's based on GOOPS, which I wanted to avoid, so I "rolled my
own", using bare structs.

Running `srfi-35.test' is roughly 3 times faster with the struct-based
version than with the GOOPS-based version (part of which is due to the
loading time of GOOPS itself).  I also measured the time taken to create
a condition type using the following snipped:

  (use-modules (srfi srfi-35))

  (let loop ((i 1000))
    (if (<= i 0)
        #t
        (let ((top (make-condition-type 'top &condition '(a b c))))
          (make-condition-type 'bottom top '(d e f))
          (loop (1- i)))))

With the GOOPS-based version, we get:

  $ time guile ,,srfi-35-prof.scm

  real    0m10.251s
  user    0m9.825s
  sys 0m0.012s

With the struct-based version:

  $ time guile -L . ,,srfi-35-prof.scm

  real    0m0.077s
  user    0m0.072s
  sys 0m0.004s

So it has the potential to improve the startup time of SRFI-35-using
programs.  ;-)

That's also an indication that it may be worth profiling `make-class'
(which is used by `make-condition-type' and Andreas' implementation).

If you have Guile-Lib installed, note that Guile-Lib's implementation
will still be used because the `site' directory appears before Guile's
directory in `%load-path'.

Thanks,
Ludovic.