task is a construct which is comparable to a dialog. However,
tasks are meant for non-interactive, non-interruptible computations, therefore,
no statements are allowed that perform user-level side effects, like
Typically, tasks are executed when an event comes in:
task event: "ping" do counter = counter + 1 end
The advantage of using tasks over dialogs here is that tasks execute outside of the current dialog context. Therefore, the current dialog continues undisturbed, and the dialog stack and history remain untouched.
There fore they execute without any other effects (like
__returning__) and are
also much more performant than dialogs.
Tasks can be given a name, just like dialogs:
task calculate do result = 12345 end
These can be then executed by calling
perform from a dialog
dialog main do perform calculate say "The result is: " + result end
Just like guards in dialogs, tasks can have a guard clause which will decide whether the task will be executed or not.
task calculate when user.frontend == "slack" do revenue = revenue + 200 end task calculate do revenue = revenue + 100 end
Tasks can be hooked into several places while the Bubblescript interpreter does its work.
The hook is attached by creating a task which has the
before: keyword in its
declaration. Tasks like these are executed before the event occurs.
All tasks with a before: hook are executed one after the other, not just the first one like with
task before: dialog¶
Executed just before the dialog with the given name is executed.
dialog main do say welcome end task before: main do welcome = "Good afternoon" end
task before: __resolve__¶
This task is execued just before the Bubblescript interpreter starts looking for
message triggers; e.g. when the users sends a message that is not caught by an
ask and starts bubbling up in the dialog stack.
For instance, it can be used to perform basic classification. The user's
utterance is stored in the
task before: __resolve__ do branch do message =~ "invoice" -> topic = "invoice" true -> topic = "unknown" end end dialog __unknown__ do say topic end
task before: __user_message__¶
before: __user_message__ hook gets executed any time a user's message
enters into the system, regardless of it being caught by an
ask or not. This
hook can also be used to enrich the
message variable with extra metadata.