wanted function

[sineptic]

Is there any function that read only if in input pattern occurs EXACTLY N times. existed function exactly() read even if there more than N occurs.

// This don't work:
let pattern = || {...};
let a = || read_until(pattern().repeated().exactly(N).then_ignore(pattern().not().rewind()));

// Example
let N = 2;
let pattern = || just::<_, Simple<_>>('a');
let a = ...;
assert!(a().parse("aaa ").is_ok());

//  ++-        +++
// "a̲aa " -> "aa̲a "

And I can't read already processed input.

[sineptic]

More general, I need function, that return only if pattern matches after not match.

I need matches equal number of backticks, but

_```abc``_ matches with _`_ | _``abc``_

[sineptic]

I think to work it must be names smth like (take/skip)_until_exactly

[zesterer]

You can do a.repeated().exactly(n).then_ignore(a.not()).

The final part expects anything that isn't an a immediately after the repeating section, effectively preventing more than n instances ever occurring.

[zesterer]

That said, the pattern you are looking for (the backticks) is context-sensitive and won't be solved with this alone. See my response here about parsing Rust-like raw strings, which pretty much follow the same pattern: #441 (reply in thread)

[sineptic]

You can do a.repeated().exactly(n).then_ignore(a.not()).

The final part expects anything that isn't an a immediately after the repeating section, effectively preventing more than n instances ever occurring.

It don't works with my example