nom::character contains only a subset of parsers from complete/streaming

[stevenengler]

In nom 8.0, there is a new way of writing parsers using a Parser trait. Some of nom's parsers are now written using this Parser trait, and some using the older function syntax.

In nom::character::complete and nom::character::streaming, there are many parsers:

• alpha0
• alpha1
• digit0
• digit1
• newline
• etc

These all seem to be written using the old function syntax. For example:

pub fn digit1<T, E: ParseError<T>>(input: T) -> IResult<T, T, E>
where
    T: Input,
    <T as Input>::Item: AsChar,

In nom::character, there are a small subset of these parsers:

• digit1
• char
• etc

These seem to be written using the new Parser trait. For example:

pub fn digit1<T, E: ParseError<T>>() -> impl Parser<T, Output = T, Error = E>
where
    T: Input,
    <T as Input>::Item: AsChar,

But notably many of the parsers from the complete and streaming modules like digit0, alpha0, alpha1, etc are missing. For example this module has a digit1 but not a digit0.

So as a user, it's unclear when parsers should be used from the parent nom::character or the child complete/streaming. And it's also not clear why nom::character is missing so many compared to complete/streaming. I think this could be documented better.