Function one_of 

pub fn one_of<'i, L: ParserOneOfTuple<'i>>(options: L) -> OneOf<L>

Parser which tries a list of parsers in order until one succeeds.

If a parser commits, no further parsers are tried.

This is similar to Parser::or but supports a variable number of parsers.

Prefer parser::literal_map if all the parsers are string literals.

Examples

#[derive(Debug, PartialEq)]
enum Value {
    Unsigned8(u8),
    Unsigned32(u32),
    Signed8(i8),
    Signed32(i32),
}

let parser = parser::one_of((
    parser::u8().map(Value::Unsigned8),
    parser::u32().map(Value::Unsigned32),
    parser::i8().map(Value::Signed8),
    parser::i32().map(Value::Signed32),
));

assert_eq!(
    parser.parse_complete("31").unwrap(),
    Value::Unsigned8(31),
);
assert_eq!(
    parser.parse_complete("4294967295").unwrap(),
    Value::Unsigned32(4294967295),
);
assert_eq!(
    parser.parse_complete("-1").unwrap(),
    Value::Signed8(-1)
);
assert_eq!(
    parser.parse_complete("-2147483648").unwrap(),
    Value::Signed32(-2147483648)
);

assert_eq!(
    parser.parse_complete("not a number").unwrap_err().into_source(),
    ParseError::Expected("unsigned integer")
);
assert_eq!(
    parser.parse_complete("-4294967295").unwrap_err().into_source(),
    ParseError::NumberTooSmall(-2147483648)
);