Using Repeat in seq! or a better way to do what im trying to do

[SelectSweet]

Hi, I'm fairly new to using Winnow and parser combinators in general, so I'm not sure how to deal with the errors that I'm facing. What I am trying to parse at the moment is the following:

cat(l: "test", j: "Name");

Using the following functions:

pub fn Fields<'a>(input: &mut TokenSlice<'a>) -> Result<Vec<String>, ErrMode<ContextError>> {
    let field = seq!(identifier, Fieldsep, Type, opt(Comma))
        .take()
        .map(|t| {
            let mut res_vec = Vec::new();

            for f in t.iter() {
                res_vec.push(f.text.to_string());
            }

            res_vec
        })
        .parse_next(input);

    return field;
}

pub fn FunCall<'a>(input: &mut TokenSlice<'a>) -> Result<Vec<String>, ErrMode<ContextError>> {
    let res: Result<Vec<String>, ErrMode<ContextError>> = seq!(
        identifier,
        OpenParen,
        repeat(0.., Fields).take(),
        CloseParen,
        SemiColon
    )
    .take()
    .map(|t| {
        let mut res_vec = Vec::new();

        for f in t.iter() {
            res_vec.push(f.text.to_string());
        }

        res_vec
    })
    .parse_next(input);

    return res;
}

When the second field in the cat function call is not there and the repeat in the FunCall function is replaced with just Fields it works. However, when they are there, I get this unhelpful error, which repeats multiple times:

error[E0283]: type annotations needed
  --> src/parse.rs:44:29
   |
41 |       let res: Result<Vec<String>, ErrMode<ContextError>> = seq!(
   |  ___________________________________________________________-
42 | |         identifier,
43 | |         OpenParen,
44 | |         repeat(0.., Fields).take(),
   | |                             ^^^^
45 | |         CloseParen,
46 | |         SemiColon
47 | |     )
   | |_____- type must be known at this point
   |
   = note: multiple `impl`s satisfying `_: Accumulate<Vec<String>>` found in the `winnow` crate:
           - impl<K, S> Accumulate<K> for HashSet<K, S>
             where K: Eq, K: Hash, S: BuildHasher, S: Default;
           - impl<K> Accumulate<K> for BTreeSet<K>
             where K: Ord;
           - impl<T> Accumulate<T> for ();
           - impl<T> Accumulate<T> for Vec<T>;
           - impl<T> Accumulate<T> for usize;
   = note: required for `Repeat<fn(&mut &[Token<'a>]) -> Result<Vec<String>, ErrMode<ContextError>> {Fields}, &[Token<'_>], Vec<String>, _, ...>` to implement `winnow::Parser<&[tokenise::Token<'_>], _, winnow::error::ContextError>`
   = note: 2 redundant requirements hidden
   = note: required for `(fn(&mut &[Token<'a>]) -> Result<String, ErrMode<ContextError>> {identifier}, fn(&mut &...) -> ... {OpenParen}, ..., ..., ...)` to implement `winnow::Parser<&[tokenise::Token<'_>], (String, String, &[tokenise::Token<'_>], String, String), winnow::error::ContextError>`
   = note: the full name for the type has been written to '/home/gbox/Documents/1. Varied Project/DFL/target/debug/deps/DFL-743fb610d4023366.long-type-10044060789004219304.txt'
   = note: consider using `--verbose` to print the full type name to the console
help: try using a fully qualified path to specify the expected types
   |
44 |         <winnow::combinator::Repeat<_, &[tokenise::Token<'_>], Vec<String>, Accumulator, winnow::error::ContextError> as winnow::Parser<&[tokenise::Token<'_>], O, winnow::error::ContextError>>::take(repeat(0.., Fields)),
   |         +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++   

So I'm just wondering what I'm missing, as the error mentions missing type annotations. However, I'm unsure how to declare them, as declaring it at the start of the variable didn't help. Or if I'm just missing something, or if there is a better way to do it

[epage]

repeats output is generic but take() ignores the output and provides a different one, so the compiler can't determine what type to use for repeat. Adding a type annotation to res doesn't work because a map operation happens. map doesn't work because that is appying to another take().

What you can do is repeat(...).map(|()| ()).take()

[SelectSweet]

That Fixed it

[epage]

I wish I could come up with a way to encapsulate this so its a little lessy noisy but haven't found one yet.