use proc_macro2::{Delimiter, TokenStream, TokenTree}; use std::hash::{Hash, Hasher}; pub(crate) struct TokenTreeHelper<'a>(pub &'a TokenTree); impl<'a> PartialEq for TokenTreeHelper<'a> { fn eq(&self, other: &Self) -> bool { use proc_macro2::Spacing; match (self.0, other.0) { (TokenTree::Group(g1), TokenTree::Group(g2)) => { match (g1.delimiter(), g2.delimiter()) { (Delimiter::Parenthesis, Delimiter::Parenthesis) | (Delimiter::Brace, Delimiter::Brace) | (Delimiter::Bracket, Delimiter::Bracket) | (Delimiter::None, Delimiter::None) => {} _ => return false, } let s1 = g1.stream().into_iter(); let mut s2 = g2.stream().into_iter(); for item1 in s1 { let item2 = match s2.next() { Some(item) => item, None => return false, }; if TokenTreeHelper(&item1) != TokenTreeHelper(&item2) { return false; } } s2.next().is_none() } (TokenTree::Punct(o1), TokenTree::Punct(o2)) => { o1.as_char() == o2.as_char() && match (o1.spacing(), o2.spacing()) { (Spacing::Alone, Spacing::Alone) | (Spacing::Joint, Spacing::Joint) => true, _ => false, } } (TokenTree::Literal(l1), TokenTree::Literal(l2)) => l1.to_string() == l2.to_string(), (TokenTree::Ident(s1), TokenTree::Ident(s2)) => s1 == s2, _ => false, } } } impl<'a> Hash for TokenTreeHelper<'a> { fn hash(&self, h: &mut H) { use proc_macro2::Spacing; match self.0 { TokenTree::Group(g) => { 0u8.hash(h); match g.delimiter() { Delimiter::Parenthesis => 0u8.hash(h), Delimiter::Brace => 1u8.hash(h), Delimiter::Bracket => 2u8.hash(h), Delimiter::None => 3u8.hash(h), } for item in g.stream() { TokenTreeHelper(&item).hash(h); } 0xffu8.hash(h); // terminator w/ a variant we don't normally hash } TokenTree::Punct(op) => { 1u8.hash(h); op.as_char().hash(h); match op.spacing() { Spacing::Alone => 0u8.hash(h), Spacing::Joint => 1u8.hash(h), } } TokenTree::Literal(lit) => (2u8, lit.to_string()).hash(h), TokenTree::Ident(word) => (3u8, word).hash(h), } } } pub(crate) struct TokenStreamHelper<'a>(pub &'a TokenStream); impl<'a> PartialEq for TokenStreamHelper<'a> { fn eq(&self, other: &Self) -> bool { let left = self.0.clone().into_iter().collect::>(); let right = other.0.clone().into_iter().collect::>(); if left.len() != right.len() { return false; } for (a, b) in left.into_iter().zip(right) { if TokenTreeHelper(&a) != TokenTreeHelper(&b) { return false; } } true } } impl<'a> Hash for TokenStreamHelper<'a> { fn hash(&self, state: &mut H) { let tts = self.0.clone().into_iter().collect::>(); tts.len().hash(state); for tt in tts { TokenTreeHelper(&tt).hash(state); } } }