A possible interface for thread local variables:
(thread-local-set! key val) (thread-local-ref key #!optional (default (macro-absent-obj))) ; when unbound returns default or raises if absent
and thread-cells can be implemented on top with a struct and a gensym.
-- vyzo
On Sat, Mar 10, 2018 at 4:16 PM, Dimitris Vyzovitis vyzo@hackzen.org wrote:
Also, we don't have to follow the plt interface -- we can just call them thread-local-variables :)
-- vyzo
On Sat, Mar 10, 2018 at 3:45 PM, Dimitris Vyzovitis vyzo@hackzen.org wrote:
Marc,
Could we add thread-cells? They can be easily implemented with a per-thread hash-table, that only gets initialized if accessed.
They are incredibly useful for per thread caches, and probably a lot of other things.
For instance, I have this common pattern that i see a lot:
(def errptr-cache (make-hash-table-eq weak-keys: #t)) (def errptr-cache-mutex (make-mutex))
(def (get-errptr) (with-lock errptr-cache-mutex (lambda () (cond ((hash-get errptr-cache (current-thread)) => (lambda (errptr) (errptr_clear errptr) errptr)) (else (let (errptr (check-ptr get-errptr (make_errptr))) (hash-put! errptr-cache (current-thread) errptr) errptr))))))
and I would like to eliminate both the lock and the weak table.
I can add it and make a pr, but I wanted to consult with you first.
-- vyzo