A minimal publish/subscribe mechanism. Packages that finish a top-level
fit, simulation or result call rxEventEmit(); listeners registered with
rxEventListen() are told about it. Events are only delivered from the
outermost operation: work done inside rxEventScope() (or between
.rxEventEnter() and .rxEventExit()) emits nothing.
Usage
rxEventListen(id, fun)
rxEventUnlisten(id)
rxEventListeners()
rxEventDepth()
rxEventSeq()
rxEventScope(expr)
.rxEventEnter()
.rxEventExit(event = NULL, ..., fun = NULL)
.rxEventCall(call, fun = NULL)
rxEventEmit(event, ..., fun = NULL)Arguments
- id
A listener id; registering the same id again replaces it.
- fun
For
rxEventListen(), the listener, a functionfunction(event, ...). ForrxEventEmit(),.rxEventExit()and.rxEventCall(), the name of the emitting function, used to normalize acallpayload field (see Details).- expr
Code to evaluate inside an operation scope.
- event
The event name, e.g.
"fitComplete"or"solveComplete".- ...
Payload fields (named).
- call
A call to normalize.
Value
rxEventListen(), rxEventUnlisten() and rxEventEmit() return
NULL invisibly; rxEventListeners() returns the listener ids;
rxEventDepth() the current depth; rxEventSeq() the number of events
delivered in this process; rxEventScope() the value of expr.
Details
Listeners are called as fun(event, ...) with the event name and the
payload fields as named arguments. A listener that errors gives a warning
and never stops the other listeners or the caller. Events emitted while a
listener runs are dropped.
A call payload field is passed through .rxEventCall(): its head
becomes fun (when given; otherwise a function object in the head becomes
`<fun>`). Arguments that are not language (values inlined by
do.call()) become `<value>`, except single constants; when there
are more than five such values they are all dropped and replaced by one
`<...>` marker. A recorded call therefore never embeds a large
object.