Trait regex_syntax::hir::Visitor

source ·

pub trait Visitor {
    type Output;
    type Err;

    // Required method
    fn finish(self) -> Result<Self::Output, Self::Err>;

    // Provided methods
    fn start(&mut self) { ... }
    fn visit_pre(&mut self, _hir: &Hir) -> Result<(), Self::Err> { ... }
    fn visit_post(&mut self, _hir: &Hir) -> Result<(), Self::Err> { ... }
    fn visit_alternation_in(&mut self) -> Result<(), Self::Err> { ... }
    fn visit_concat_in(&mut self) -> Result<(), Self::Err> { ... }
}

Expand description

A trait for visiting the high-level IR (HIR) in depth first order.

The principle aim of this trait is to enable callers to perform case analysis on a high-level intermediate representation of a regular expression without necessarily using recursion. In particular, this permits callers to do case analysis with constant stack usage, which can be important since the size of an HIR may be proportional to end user input.

Typical usage of this trait involves providing an implementation and then running it using the visit function.