Enum Rule 

pub enum Rule<'a> {
    Text(Cow<'a, str>),
    Choice(Cow<'a, [&'a Rule<'a>]>),
    Sequence(Cow<'a, [&'a Rule<'a>]>),
    Repeat(RepeatRange, &'a Rule<'a>),
    Semantic(SemanticValue<Cow<'a, str>>, &'a Rule<'a>),
}

A rule that defines one or more phrases or fragments that can be recognized by the engine.

Variants

Text(Cow<'a, str>)

A sequence of words

Choice(Cow<'a, [&'a Rule<'a>]>)

A set of rules to choose from

Sequence(Cow<'a, [&'a Rule<'a>]>)

A sequence of rules that must be recognized in order

Repeat(RepeatRange, &'a Rule<'a>)

A rule repeated a certain number of times

Semantic(SemanticValue<Cow<'a, str>>, &'a Rule<'a>)

A rule that will produce a node in the semantic tree when recognized

Implementations

impl<'a> Rule<'a>

pub fn text<T: Into<Cow<'a, str>>>(text: T) -> Self

Creates a rule that defines a sequence of words to be recognized.

pub fn choice<L: Into<Cow<'a, [&'a Rule<'a>]>>>(options: L) -> Self

Creates a rule that defines a set of alternatives to choose from.

pub fn sequence<L: Into<Cow<'a, [&'a Rule<'a>]>>>(parts: L) -> Self

Creates a rule the defines a sequence of sub-rules that must be recognized in order.

pub fn repeat<R: Into<RepeatRange>>(times: R, target: &'a Rule<'a>) -> Self

Creates a rule that recognizes a sub-rule repeated a certain number of times.

pub fn semantic<V: Into<SemanticValue<Cow<'a, str>>>>( value: V, target: &'a Rule<'a>, ) -> Self

Creates a rule that produces a node in the resulting semantic tree when the given sub-rule is recognized.

Trait Implementations

impl<'a> Debug for Rule<'a>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.