(_
#'generic-name))))))))))
-(define-syntax-parameter >>=
+(define-syntax-rule (define-syntax-parameter-once name proc)
+ ;; Like 'define-syntax-parameter' but ensure the top-level binding for NAME
+ ;; does not get redefined. This works around a race condition in a
+ ;; multi-threaded context with Guile <= 2.2.4: <https://bugs.gnu.org/27476>.
+ (eval-when (load eval expand compile)
+ (define name
+ (if (module-locally-bound? (current-module) 'name)
+ (module-ref (current-module) 'name)
+ (make-syntax-transformer 'name 'syntax-parameter
+ (list proc))))))
+
+(define-syntax-parameter-once >>=
;; The name 'bind' is already taken, so we choose this (obscure) symbol.
(lambda (s)
(syntax-violation '>>= ">>= (bind) used outside of 'with-monad'" s)))
-(define-syntax-parameter return
+(define-syntax-parameter-once return
(lambda (s)
(syntax-violation 'return "return used outside of 'with-monad'" s)))