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Navigating in a CSML Bot
A flow is made of at least one step (called
start
), but can also contain as many steps as necessary. You should think of steps as individual, simple bits of logic, linked inside the same conversation topic (which is the flow).To go from one step to the next, you can simply use the keyword
goto
(or goto step
) followed by the name of the step.To finish a flow (and close the conversation), add
goto end
.start:
say "hi"
goto step otherstep // note: in the following examples, we will use the shorthand notation `goto otherstep`
otherstep:
say "I'm in otherstep"
goto end
If, at the end of a step, the
goto end
instruction is omitted, the conversation will be closed anyway. In other words,
goto end
can be used to exit of a conversation early at any point, but it is implicitly added at the end of all steps if no other goto
instruction is present.Similarly to navigating between steps of the same flow, you can go to the beginning of any other flow by using the
goto flow
keyword. This will trigger the start
step of the target flow and close the current flow, so coming back to the first flow will actually go back to the beginning of that flow.somestep:
goto flow anotherflow
Introduced in CSML v1.2
If you want to reach a specific step in a specific flow, you can use the @ notation:
goto step_name@flow_name
This is the universal way of navigating between steps and flow. The above two methods are actually special cases of this notation:
- When the
@flow_name
part is not specified, CSML interprets it as "in the current flow". Sogoto stepname
actually is shorthand notation forgoto stepname@current_flow
, wherecurrent_flow
is dynamically matched from the name of the current flow, and works accordingly. - When the
step_name
part is not specified, CSML interprets it asstart
. So as@
means "flow",goto @flow_name
is the same asgoto start@flow_name
which is also the same asgoto flow flow_name
.
goto stepname // navigate to the step named stepname in the current flow
goto flow flowname // navigate to the start step in flow flowname
goto @flowname // navigate to the start step in flow flowname
goto stepname@flowname // navigate to step stepname in flow flowname
Introduced in CSML v1.5
As you can see above, steps and flows use strings as identifiers, but they are expressed without double quotes
"..."
. In order to navigate to dynamically set steps or flows, CSML adds a special syntax, similar to the dereference pointer concept in other languages.To go to a variable step or flow, you can reference the variable name prefixed with a
$
sign:do mystep = "somestep"
do myflow = "someflow"
goto $mystep@$myflow
Any of the syntaxes presented above are supported. For instance:
do buttons = [Button("Burgers"), Button("Vegetables")]
say Question(
"What is your favorite food?",
buttons = buttons
)
hold
do matched = event.match_array(buttons)
if (!matched) { /* handle case where input does not match anything */ }
do target = matched.title
goto flow $target
// depending on which button the user selected, this is equivalent to
// goto flow Burgers or goto flow Vegetables
Please note that dot notation (accessing child properties in an object or array, i.e
a.b
) is not supported in variable flow and step names.Last modified 2yr ago