Macro abortable_parser::optional [−][src]
macro_rules! optional { ($i:expr, $f:ident) => { ... }; ($i:expr, $f:ident!( $( $args:tt )* ) ) => { ... }; (__impl $i:expr, $f:ident!( $( $args:tt )* )) => { ... }; }
Treats a sub parser as optional. It returns Some(output) for a successful match and None for failures.
use abortable_parser::iter; let input_str = "foo"; let iter = iter::SliceIter::new(input_str.as_bytes()); let result = optional!(iter, text_token!("foo"));