Struct Usefulness

pub struct Usefulness<G> { /* private fields */ }

Contains the information about usefulness of the grammar’s rules. Useful rules are both reachable and productive.

Implementations

impl<'a, G> Usefulness<&'a mut G>

where G: RuleContainer,

pub fn new(grammar: &'a mut G) -> Usefulness<&'a mut G>

Analyzes usefulness of the grammar’s rules. In particular, it checks for reachable and productive symbols.

pub fn productivity(&self, sym: Symbol) -> bool

Checks whether a symbol is productive. Can be used to determine the precise reason of a rule’s unproductiveness.

pub fn reachable<Sr>(self, syms: Sr) -> Self

where Sr: AsRef<[Symbol]>,

Sets symbol reachability. Takes an array of reachable symbols.

pub fn all_useful(&self) -> bool

Checks whether all rules in the grammar are useful.

pub fn all_productive(&self) -> bool

Checks whether all rules in the grammar are productive.

pub fn all_reachable(&self) -> bool

Checks whether all rules in the grammar are reachable.

pub fn rule_usefulness(&self, rule: RuleRef<'_>) -> RuleUsefulness

pub fn useless_rules( &'a self, ) -> UselessRules<'a, G, impl Iterator<Item = RuleRef<'a>>>

Returns an iterator over the grammar’s useless rules.

impl<'a, G> Usefulness<&'a mut G>

where G: RuleContainer,

pub fn remove_useless_rules(&mut self)

Removes useless rules. The language represented by the grammar doesn’t change.