Expand description
Fail with a message.
use memoir::*;
use memoir::result::Error;
let parser = symbol('!').or(fail("only `!` is allowed"));
assert_eq!(parser.parse("?").err(), Some((Error::new("only `!` is allowed"), "?")));
Fail with a message.
use memoir::*;
use memoir::result::Error;
let parser = symbol('!').or(fail("only `!` is allowed"));
assert_eq!(parser.parse("?").err(), Some((Error::new("only `!` is allowed"), "?")));