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use crate::parse::ParseStream;
use proc_macro2::{Delimiter, TokenStream};
use std::cmp::Ordering;
use std::iter;
pub(crate) fn between<'a>(begin: ParseStream<'a>, end: ParseStream<'a>) -> TokenStream {
let end = end.cursor();
let mut cursor = begin.cursor();
assert!(crate::buffer::same_buffer(end, cursor));
let mut tokens = TokenStream::new();
while cursor != end {
let (tt, next) = cursor.token_tree().unwrap();
if crate::buffer::cmp_assuming_same_buffer(end, next) == Ordering::Less {
// A syntax node can cross the boundary of a None-delimited group
// due to such groups being transparent to the parser in most cases.
// Any time this occurs the group is known to be semantically
if let Some((inside, _span, after)) = cursor.group(Delimiter::None) {
assert!(next == after);
cursor = inside;
continue;
} else {
panic!("verbatim end must not be inside a delimited group");
}
}
tokens.extend(iter::once(tt));
cursor = next;
}
tokens
}