Struct GrammarBuilder 

pub struct GrammarBuilder<'a> { /* private fields */ }

Helper type that constructs a grammar from a set of top-level rules.

A top-level rule defines one or more phrases that can be recognized. The rules contained in or referenced by a top-level rule will not be recognized as phrases, unless they are also added as top-level rules. For example, consider the following top-level rule definition:

Rule::sequence(vec![
    &Rule::text("good"),
    &Rule::choice(vec![
        &Rule::text("morning"),
        &Rule::text("evening"),
    ])
])

Given this rule, the engine will only recognize the phrases “good morning” and “good evening”, but not “good”, “morning”, or “evening”.

Implementations

impl<'a> GrammarBuilder<'a>

pub fn clear(&mut self) -> &mut Self

Clears all the added rules.

pub fn add_rule(&mut self, rule: &'a Rule<'a>) -> &mut Self

Adds an unnamed top-level rule to the grammar.

pub fn add_named_rule<S: Into<Cow<'a, str>>>( &mut self, name: S, rule: &'a Rule<'a>, ) -> &mut Self

Adds a top-level rule with the given name to the grammar. The name can be used to enable or disable the rule.

pub fn build(&mut self) -> Result<Grammar>

Builds the grammar from the given rules and loads it into the recognition context. The newly loaded grammar must be enabled before the engine will start recognizing phrases from it.