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 // irrelevant. https://github.com/dtolnay/syn/issues/1235 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 }