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