This tag describes input or custom pattern.

It may contain:


Pattern matching is a base Zenbot's technology. It enables Zenbot to quickly match user's text input through a set of input patterns to search the most appropriate context.

Read more about patterns and pattern matching in the special chapter.

Input and custom patterns

There are two different types of patterns in Zenbot - custom and input.

Custom patterns

This type of patterns doesn't take a part in the context pattern matching, but it provides a source for another patterns.

There is an example of such custom pattern:

  <pattern name="Fruit" value="(apple*|orange*)"/> <!-- Custom pattern -->

    <pattern value="* (want|wanna) * $Fruit *"/> <!-- Input pattern -->

There we have two patterns: one with name “Fruit” and another inside one of context's inputs.

Fruit pattern doesn't take a part in the input, so it only provides a source for another patterns. This way it can be reused in any pattern (custom or input) inside this or nested contexts and inputs.

  So if user says something like "Apple" or "Orange" nothing happens. The context's input will match only phrases like "I want some apple please".

Input patterns

This type of patterns lives inside the input tag and take a part in the input matching process.

Unlike the custom patterns it don't have a names and can't be reused in another patterns.

  Regarding the example above, the second pattern is an input pattern.

Common patterns

Zenbot also provides a set of widely used common patterns for you.

Custom entities

Sometimes you cannot define a full set of patterns of some type (like cities of the world) in your Botscript.

For such type of patterns Zenbot provides a special mechanism named custom entities.

Nested patterns

It would be helpful to distribute different parts of a single pattern so it could be more readable instead of writing everything in a single pattern tag.

<pattern name="Food">
  <pattern value="(potatos|tomatos)"/>
  <pattern value="(raspberry|razz)"/>

There we have defined a custom pattern “Food” which matches such phrases as “Potatos”, “Tomatos”, “Raspberry” and “Razz”. We could define it in a single oneliner like (potatos|tomatos|raspberry|razz), but imagine if it is a really long list of variants.


value attribute

This attribute contains a pattern's content in form of pattern syntax.

  This attribute is required if you don't define pattern through nested patterns.

name attribute

Defines a unique name of the custom pattern. You can then reference such pattern inside another one by this name, using $ symbol before the name.

  This attribute is required for custom patterns only. It doesn't affect input patterns.

Do not use any special symbols and pattern syntax reserved symbols and words in the name of your patterns. Also note that each name must be unique through all patterns in your Botscript and it must not clash with common patterns.