You can carry out conditional logic in scenes using values from the Data model objects. The following sections describe the valid syntax for conditions.
Logical operators
Operator | Description |
---|---|
&& |
Logical AND. Inner expressions are evaluated iteratively, and the evaluation is short-circuited if any expression evaluates to false. | || |
Logical OR. Inner expressions are evaluated iteratively, and the evaluation is short-circuited if any expression evaluates to true |
! |
Logical NOT. The evaluation of the inner expression is negated |
Numerical and string operators
The following numerical and string operators are supported:
Operator | Description |
---|---|
+ |
Add numbers or string concatenation |
- |
Subtract numbers |
* |
Multiply numbers |
/ |
Divide numbers |
Booleans
The following constant booleans are supported:
Constant | Description |
---|---|
true |
Must be lowercase |
false |
Must be lowercase |
!false |
Evaluates to true . Must be lowercase. |
Comparison operators
The following comparison operators are provided:
Operator | Description |
---|---|
== |
Equals |
!= |
Not equals |
< |
Less than |
<= |
Less than equals |
> |
Greater than |
>= |
Greater than equals |
Lists and maps
Given a list named session.params.myList
:
Syntax | Description |
---|---|
x in session.params.myList |
Returns true if the value x is in
session.params.myList |
myList[x] |
Returns the value at index x of myList |
size(session.params.myList) |
Returns the size of a list |
Given a map named session.params.myMap
:
Syntax | Description |
---|---|
session.params.myMap == {"one": 1, "two":2} |
Returns true if maps are equal |
session['params']['myMap']['one'] |
Returns the value with specified key |
size(session.params.myMap) |
Returns the map size |
Data model
The following objects can be used within scene conditions:
Syntax | Description |
---|---|
intent |
Matched intent parameter data |
scene |
Slot-filling data |
session |
Session storage data |
user |
User storage data |
home |
Home storage data |
device |
Device capability and location data |
canvas |
Canvas state data |
resources |
Localized project resources (audio, images, strings, etc.) data |
The following is an example snippet of the full data model in JSON:
{
"intent": {
"params": {
"<param_name>": {
"original": "five people",
"resolved": 5
}
}
},
"session": {
"params": {
"<session_params_key>": "<session_params_value>"
}
},
"scene": {
"slots": {
"status": "FINAL",
"params": {
"<slot_name>": "<slot_value>"
}
}
},
"user": {
"params": {
"<user_params_key>": "<user_params_value>"
},
"permissions": [
"DEVICE_PRECISE_LOCATION"
],
"accountLinkingStatus": "LINKED",
"verificationStatus": "VERIFIED",
"lastSeenTime": {
"seconds": 123,
"nanos": 456
},
"engagement": {
"pushNotificationIntents": [
"intent1",
"intent2"
]
}
},
"home": {
"params": {
"<home_params_key>": "<home_params_value>"
}
},
"canvas": {
"state": {
"<canvas_state_key>": "<canvas_state_value>"
}
},
"device": {
"capabilities": [
"SPEECH",
"RICH_RESPONSE",
"LONG_FORM_AUDIO",
"INTERACTIVE_CANVAS"
],
"currentLocation": {
"coordinates": {
"latitude": 37.422,
"longitude": -122.084
},
"postalAddress": {
"revision": 0,
"regionCode": "US",
"languageCode": "en",
"postalCode": "94043",
"sortingCode": "",
"administrativeArea": "California",
"locality": "Mountain View",
"sublocality": "",
"addressLines": ["1600 Amphitheatre Parkway"],
"recipients": [],
"organization": ""
}
}
},
"resources": {
"strings": {
"<resource_string_key>": "<resource_string_value>"
},
"images": {
"<resource_image_key>": "<resource_image_value>"
}
}
}
Usage reference
The following syntax examples assumes you are working
with session.params
object:
session.params = {
"flag": true,
"count": 10,
"name": "john smith",
"myList": [1, 2, 3],
"myMap": {"one": 1, "two":2}
}
You can carry out the following conditional operations:
// numbers and boolean logic
session.params.count > 0 && session.params.count < 100 // AND
session.params.count == 0 || session.params.count != 5 // OR
!(session.params.count <= 0) // NOT
// booleans
!false // true constant
session.params.flag // boolean variable
session.params.flag == true // explicitly compare with true constant
// strings
session.params.name == "john smith" // double quotes supported
session.params.name == 'john smith' // single quotes supported
session.params.name.contains("john") // substring
session.params.name + "!!!" == "john smith!!!" // string concatenation
session.params.name < "abc" // compares lexicographically
size(session.params.name) == 10 // length of string
// lists
1 in session.params.myList // "contains in list" operator
session.params.myList[0] == 1 // "index into list" operator
size(session.params.myList) == 3 // returns number of elements in the list
// maps
session.params.myMap == {"one": 1, "two":2} // compare map with json
session['params']['myMap']['one'] == 1 // index using square brackets
size(session.params.myMap) == 2 // number of entries in the map