publish and surprise

[Paul Dupuis]

I would love to see a publish and subscribe system in the engine for use 
in Standalone.

I've written a LCS library for for publish and subscribe within our 
commercial apps, but would toss it in an instant for a good engine 
implementation.

Beyond abstracted commands like:
revIDESubscribe "helloworld" -> subscribe <messageName>
ideMessageSendWithParameters "helloworld" -> publish <messageName> with 
<parameters>, which could just be existing "send" or "dispatch"

You need a general suppress messages/unsuppress messages, which we have 
as "lock messages" and "unlock messages" already in the language.

You also need an "unsubscribe <messageName>" and a "lock <messageName> 
messages [for <object>]" / "unlock <messageName> messages [for 
<object>]" to allow suppression/unsuppression of a specific message for 
all objects or for specific object.

We already have "the pendingMessages" and "cancel", but you would also 
want to add "the subscribers [of <messageName>]" for a list of long IDs 
of objects and their messages or filtered for a specific message 
subscribed to and "the publishers [of <messageName>]" for a similar list 
of object IDs when the messages they publish or filtered for a specific 
message.

Or perhaps I have been thinking too much about this!


On 10/2/2019 8:58 AM, Tom Glod via use-livecode wrote:
> thats what i'm thiking about..its only documented in the "create a plugin"
> sections.  But having this in standalones would be a bit of news.
>
> So every message the engine sends is checked to see if there is a
> subscription to that message and then all objects ( whether in the path or
> not. ) that are subscribed would receive a message that this message was
> triggered. That is pretty cool!
>
> On Wed, Oct 2, 2019 at 8:53 AM Paul Dupuis via use-livecode <
> use-livecode at lists.runrev.com> wrote:
>
>> On 10/1/2019 11:52 PM, Mark Wieder via use-livecode wrote:
>>> I have finally gotten around to noticing that LC9.x builds have opened
>>> the publish-and-subscribe mechanism to arbitrary messages. I'm not
>>> sure when this happened and I'm really not inclined to go searching
>>> through all those release notes, but I'm ecstatic over the surprise
>>> discovery. This means objects can register interest in certain
>>> messages to do something like
>>>
>>> object1:
>>> revIDESubscribe "helloworld"
>>>
>>> object2:
>>> revIDESubscribe "helloworld"
>>>
>>> object3:
>>> ideMessageSendWithParameters "helloworld"
>>>
>>> and both object1 and object2 will get notifications, fully
>>> implementing the Publish-and-Subscribe design pattern.
>>>
>>> Thank you team.
>>>
>> Have you tested this is a standalone?
>>
>> I thought (probably incorrectly) that revIDE... functions/commands were
>> only available when running in the IDE?
>>
>>
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>