And here’s a reduced test case that “works” quite well on Guile 2.0.9:
--8<---------------cut here---------------start------------->8---
(use-modules (ice-9 threads)
(ice-9 regex)
(web uri)
(srfi srfi-1)
(srfi srfi-26))
(let ((do-regexps (lambda ()
(define seed1 (random 100000))
(define seed2 (random 100000))
(let loop ()
(let ((p (make-regexp "^http://([^/]+)/(.*)$"))
(s (string-append
"http://"; (number->string seed1)
"hydra.gnu.org/nar/0did57blsaaspj49cl3q8nnydm5pr1qg-cflow-1.4"
(number->string seed2))))
(or (uri? (string->uri s))
(exit 42))
(regexp-exec p s)
(loop))))))
(unfold (cute >= <> (current-processor-count))
(lambda (i)
(call-with-new-thread do-regexps))
1+
0)
(do-regexps))
--8<---------------cut here---------------end--------------->8---
Ludo’.
