added example for one_of_with_error

crates/compiler/parse/src/parser.rs

@@ -1799,6 +1799,36 @@ macro_rules! one_of {
     };
 }
 
+/// # Examples
+/// ```
+/// # use roc_parse::state::{State};
+/// # use crate::roc_parse::parser::{Parser, Progress, Progress::{MadeProgress, NoProgress}, word, word1};
+/// # use roc_region::all::{Loc, Position};
+/// # use roc_parse::ident::lowercase_ident;
+/// # use roc_parse::one_of_with_error;
+/// # use bumpalo::Bump;
+/// # #[derive(Debug, PartialEq)]
+/// # enum Problem {
+/// #     NotFound(Position),
+/// #     Other(Position),
+/// # }
+/// # let arena = Bump::new();
+/// # fn foo<'a>(arena: &'a Bump) {
+/// let parser = one_of_with_error!(
+///     Problem::Other;
+///     word("hello", Problem::NotFound)
+/// );
+/// let (progress, output, state) = parser.parse(&arena, State::new("hello, world".as_bytes()), 0).unwrap();
+/// assert_eq!(progress, Progress::MadeProgress);
+/// assert_eq!(output, ());
+/// assert_eq!(state.pos().offset, 5);
+///
+/// let (progress, err) = parser.parse(&arena, State::new("bye, world".as_bytes()), 0).unwrap_err();
+/// assert_eq!(progress, Progress::MadeProgress);
+/// assert_eq!(err, Problem::Other(Position::new(0)));
+/// # }
+/// # foo(&arena);
+/// ```
 #[macro_export]
 macro_rules! one_of_with_error {
     ($toerror:expr; $p1:expr) => {