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
