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callbacks ​

Canonical Import ​

fennel
(local callbacks (require :callbacks))

Source Files ​

  • src/lua_callbacks.cpp
  • src/lua_runtime.cpp

What It Provides ​

callbacks registers Lua callbacks, queues payloads by id, dispatches pending callbacks, and drives polling loops for asynchronous subsystems.

API Summary ​

  • register(fn) returns a numeric callback id.
  • unregister(id) removes a registered callback and returns whether it existed.
  • enqueue(id payload) queues a payload for a registered callback.
  • dispatch([max-results]) invokes pending callbacks.
  • run-loop([opts]) repeatedly polls jobs, HTTP, process, HTTP server, and callbacks until an optional until function succeeds or timeout-ms expires. Options include poll-jobs, poll-http, poll-process, sleep-ms, timeout-ms, and until.

Examples ​

fennel
(local callbacks (require :callbacks))

(local id (callbacks.register (fn [payload] (print "payload" payload))))
(callbacks.enqueue id {:ok true})
(callbacks.dispatch)
(callbacks.unregister id)

Errors and Platform Notes ​

run-loop rejects non-numeric or negative timing values. Callback invocation errors are captured through error-reporting and printed to stderr; dispatch continues for other callbacks.

  • jobs for async job callbacks.
  • process for spawned process callbacks.

Aliases and Search Terms ​

Search terms: async callbacks, event loop, polling, dispatch queue.