Struct YaccFollows

pub struct YaccFollows<StorageT> { /* private fields */ }

Follows stores all the Follow sets for a given grammar. For example, given this code and grammar:

  let grm = YaccGrammar::new(YaccKind::Original(YaccOriginalActionKind::GenericParseTree), "
      S: A 'b';
      A: 'a' | ;
    ").unwrap();
  let follows = Follows::new(&grm);

then the following assertions (and only the following assertions) about the Follows set are correct:

  assert!(follows.is_set(grm.rule_idx("S").unwrap(), grm.eof_token_idx());
  assert!(follows.is_set(grm.rule_idx("A").unwrap(), grm.token_idx("b").unwrap()));

Implementations

impl<StorageT: 'static + PrimInt + Unsigned> YaccFollows<StorageT>

where usize: AsPrimitive<StorageT>,

pub fn new(grm: &YaccGrammar<StorageT>) -> Self

Generates and returns the Follows set for the given grammar.

pub fn follows(&self, ridx: RIdx<StorageT>) -> &Vob

Return the Follows Vob for rule ridx.

pub fn is_set(&self, ridx: RIdx<StorageT>, tidx: TIdx<StorageT>) -> bool

Returns true if the token tidx is in the follow set for rule ridx.

Trait Implementations

impl<StorageT: Debug> Debug for YaccFollows<StorageT>

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

Formats the value using the given formatter.