SAL syntax consists of Annotation syntax and Template notation.

Annotation syntax

The annotation syntax is used to annotate intents and entities.

Intent

Intents are defined by prepending the example with *intent_name. The remaining sentence after the *intent_name part will be recognized as having intent intent_name.

For example:

*show_products show all products

An end user utterance “Show all products” will return the intent show_products

Entity

Entities are defined by [entity value](entity name) notation.

For example:

*show_products show [jeans](category)

An end user utterance “Show jeans” will return the value jeans for entity name category.

Template notation

Template notation is used to define Templates that are expanded to Example utterances during deployment. See also SAL Semantics for a more detailed description about how Example utterances and Templates relate to each other.

Lists

Lists are defined by [exp1 | exp2 | ... | exp_N], where exp1, exp2 … are arbitrary SAL expressions.

When a template having a list is expanded, only one of the list elements is used in the final example utterance. For example, the template:

*show_products [show | view | i want to see] products

Is equivalent to writing

*show_products show products
*show_products view products
*show_products i want to see products

Optional parts

A substring of an example utterance can be declared as optional by enclosing it in curly braces {this substring is optional}. The optional part can be an arbitrary SAL expression.

The optional parts of an example utterance may or may not exist. The template

*show_products {show} products {please}

is equivalent to writing

*show_products show products please
*show_products show products
*show_products products please
*show_products products

Variables

Variables are declared with the syntax variable_name = arbitrary-SAL-expression, and their value is accessed by $variable_name. You can assign any arbitrary SAL expression to a variable.

For example, a common use case for variables are lists of various entity values:

categories = [jeans | shoes | shirts | accessories]
*show_products show $categories(category)

Note that above $categories(category) is shorthand for [$categories](category). When the entity value is looked up from a variable, the brackets are not necessary.

Variables can also be used to assemble complex phrases from simple components

digit = [one | two | three | four | five | six | seven | eight | nine | zero]
symbol = [hash | slash | dash]
product_code = $digit $digit $symbol $digit $digit $digit $digit

Above, product_code defines a template that expands to all possible utterances that start with two digits, followed by one of the symbols, followed by four digits, such as “six four dash nine nine zero four” or “one two hash three four five six”.

Note: We provide you with several predefined Standard Variables that you can take into use in your configuration! These are useful when your configuration must support numbers, dates, times, sequences of alphanumeric characters, email addresses, etc.

Every variable x must be declared in your configuration before it can be used with the $x notation. This is ok:

x = [hello | hi | greetings]
*greet $x

This is not ok:

*greet $x
x = [hello | hi | greetings]

Also, a variable declaration can not be recursive. This is thus not ok:

products = [
   jeans
   shoes
   $products
]

Permutations

A permutation generates all possible permutations of the given list of expressions. It is defined with the syntax ![exp1 | exp2 | ... | exp_N], where exp1, exp2, … can be arbitrary SAL expressions.

For example:

*book Book a ticket ![from [New York](from) | to [London](to) | for [two](num_passengers)]

is equivalent to writing:

*book Book a ticket from [New York](from) to [London](to) for [two](num_passengers)
*book Book a ticket from [New York](from) for [two](num_passengers)] to [London](to)
*book Book a ticket to [London](to) from [New York](from) for [two](num_passengers)
*book Book a ticket to [London](to) for [two](num_passengers) from [New York](from)
*book Book a ticket for [two](num_passengers) from [New York](from) to [London](to)
*book Book a ticket for [two](num_passengers) to [London](to) from [New York](from)