fn_bnf

Type Alias AnyRule

source 
pub type AnyRule<'rule, 'input, In, Out> = &'rule dyn Rule<'input, In, Output = Out>;
Expand description

Alias for a refernce to a dyn Rule object of a given type and output.

You can use this with an as cast in a match statement to allow each statement to be a separate rule:

ⓘ
t: (char, char) = Any, match arg_0 {
    'a' => &'b' as AnyRule<str, char>,
    'b' => &Any as AnyRule<str, char>,
    other => &Fail(Unexpected::new(other)) as AnyRule<str, char>
};