liminix/pkgs/devout/devout.fnl
2024-04-21 13:19:17 +01:00

48 lines
1.3 KiB
Fennel

(fn parse-uevent [s]
(let [at (string.find s "@" 1 true)
(nl nxt) (string.find s "\0" 1 true)]
(doto
(collect [k v (string.gmatch
(string.sub s (+ 1 nxt))
"(%g-)=(%g+)")]
(k:lower) v)
(tset :path (string.sub s (+ at 1) (- nl 1))))))
(fn event-matches? [e terms]
(accumulate [match? true
name value (pairs terms)]
(and match? (= value (. e name)))))
(fn find-in-database [db terms]
(accumulate [found []
_ e (pairs db)]
(if (event-matches? e terms)
(doto found (table.insert e))
found)))
(fn record-event [db subscribers str]
(let [e (parse-uevent str)]
(match e.action
:add (tset db e.path e)
:change (tset db e.path e)
;; should we do something for bind?
:remove (tset db e.path nil)
)
(each [_ { : terms : callback } (ipairs subscribers)]
(if (event-matches? e terms) (callback e)))
e))
(fn database []
(let [db {}
subscribers []]
{
:find (fn [_ terms] (find-in-database db terms))
:add (fn [_ event-string] (record-event db subscribers event-string))
:at-path (fn [_ path] (. db path))
:subscribe (fn [_ callback terms]
(table.insert subscribers {: callback : terms }))
}))
{ : database }