Struct cfg::prediction::FirstSets [−] [src]

pub struct FirstSets {
    // some fields omitted
}

FIRST sets.

Methods

`impl FirstSets`

`fn new<'a, G>(grammar: &'a G) -> Self where G: ContextFree, &'a G: ContextFreeRef<'a, Target=G>`

Compute all FIRST sets of the grammar.

We define a binary relation FIRST(N, S), in which N is related to S if the grammar has a production of the form N ⸬= α S β, where α is a nullable string of symbols.

We compute the transitive closure of this relation.

`fn first_sets(&self) -> &PerSymbolSets`

Returns a reference to FIRST sets.