//! FIXME: write short doc here #[derive(Debug, Clone)] pub(crate) struct TtIter<'a> { pub(crate) inner: std::slice::Iter<'a, tt::TokenTree>, } impl<'a> TtIter<'a> { pub(crate) fn new(subtree: &'a tt::Subtree) -> TtIter<'a> { TtIter { inner: subtree.token_trees.iter() } } pub(crate) fn expect_char(&mut self, char: char) -> Result<(), ()> { match self.next() { Some(tt::TokenTree::Leaf(tt::Leaf::Punct(tt::Punct { char: c, .. }))) if *c == char => { Ok(()) } _ => Err(()), } } pub(crate) fn expect_subtree(&mut self) -> Result<&'a tt::Subtree, ()> { match self.next() { Some(tt::TokenTree::Subtree(it)) => Ok(it), _ => Err(()), } } pub(crate) fn expect_leaf(&mut self) -> Result<&'a tt::Leaf, ()> { match self.next() { Some(tt::TokenTree::Leaf(it)) => Ok(it), _ => Err(()), } } pub(crate) fn expect_ident(&mut self) -> Result<&'a tt::Ident, ()> { match self.expect_leaf()? { tt::Leaf::Ident(it) => Ok(it), _ => Err(()), } } pub(crate) fn expect_literal(&mut self) -> Result<&'a tt::Leaf, ()> { let it = self.expect_leaf()?; match it { tt::Leaf::Literal(_) => Ok(it), tt::Leaf::Ident(ident) if ident.text == "true" || ident.text == "false" => Ok(it), _ => Err(()), } } pub(crate) fn expect_punct(&mut self) -> Result<&'a tt::Punct, ()> { match self.expect_leaf()? { tt::Leaf::Punct(it) => Ok(it), _ => Err(()), } } pub(crate) fn peek_n(&self, n: usize) -> Option<&tt::TokenTree> { self.inner.as_slice().get(n) } } impl<'a> Iterator for TtIter<'a> { type Item = &'a tt::TokenTree; fn next(&mut self) -> Option<Self::Item> { self.inner.next() } fn size_hint(&self) -> (usize, Option<usize>) { self.inner.size_hint() } } impl<'a> std::iter::ExactSizeIterator for TtIter<'a> {}