1 use proc_macro2::{Delimiter, TokenStream, TokenTree}; 2 use std::hash::{Hash, Hasher}; 3 4 pub struct TokenTreeHelper<'a>(pub &'a TokenTree); 5 6 impl<'a> PartialEq for TokenTreeHelper<'a> { eq(&self, other: &Self) -> bool7 fn eq(&self, other: &Self) -> bool { 8 use proc_macro2::Spacing; 9 10 match (self.0, other.0) { 11 (TokenTree::Group(g1), TokenTree::Group(g2)) => { 12 match (g1.delimiter(), g2.delimiter()) { 13 (Delimiter::Parenthesis, Delimiter::Parenthesis) 14 | (Delimiter::Brace, Delimiter::Brace) 15 | (Delimiter::Bracket, Delimiter::Bracket) 16 | (Delimiter::None, Delimiter::None) => {} 17 _ => return false, 18 } 19 20 let s1 = g1.stream().into_iter(); 21 let mut s2 = g2.stream().into_iter(); 22 23 for item1 in s1 { 24 let item2 = match s2.next() { 25 Some(item) => item, 26 None => return false, 27 }; 28 if TokenTreeHelper(&item1) != TokenTreeHelper(&item2) { 29 return false; 30 } 31 } 32 s2.next().is_none() 33 } 34 (TokenTree::Punct(o1), TokenTree::Punct(o2)) => { 35 o1.as_char() == o2.as_char() 36 && match (o1.spacing(), o2.spacing()) { 37 (Spacing::Alone, Spacing::Alone) | (Spacing::Joint, Spacing::Joint) => true, 38 _ => false, 39 } 40 } 41 (TokenTree::Literal(l1), TokenTree::Literal(l2)) => l1.to_string() == l2.to_string(), 42 (TokenTree::Ident(s1), TokenTree::Ident(s2)) => s1 == s2, 43 _ => false, 44 } 45 } 46 } 47 48 impl<'a> Hash for TokenTreeHelper<'a> { hash<H: Hasher>(&self, h: &mut H)49 fn hash<H: Hasher>(&self, h: &mut H) { 50 use proc_macro2::Spacing; 51 52 match self.0 { 53 TokenTree::Group(g) => { 54 0u8.hash(h); 55 match g.delimiter() { 56 Delimiter::Parenthesis => 0u8.hash(h), 57 Delimiter::Brace => 1u8.hash(h), 58 Delimiter::Bracket => 2u8.hash(h), 59 Delimiter::None => 3u8.hash(h), 60 } 61 62 for item in g.stream() { 63 TokenTreeHelper(&item).hash(h); 64 } 65 0xffu8.hash(h); // terminator w/ a variant we don't normally hash 66 } 67 TokenTree::Punct(op) => { 68 1u8.hash(h); 69 op.as_char().hash(h); 70 match op.spacing() { 71 Spacing::Alone => 0u8.hash(h), 72 Spacing::Joint => 1u8.hash(h), 73 } 74 } 75 TokenTree::Literal(lit) => (2u8, lit.to_string()).hash(h), 76 TokenTree::Ident(word) => (3u8, word).hash(h), 77 } 78 } 79 } 80 81 pub struct TokenStreamHelper<'a>(pub &'a TokenStream); 82 83 impl<'a> PartialEq for TokenStreamHelper<'a> { eq(&self, other: &Self) -> bool84 fn eq(&self, other: &Self) -> bool { 85 let left = self.0.clone().into_iter().collect::<Vec<_>>(); 86 let right = other.0.clone().into_iter().collect::<Vec<_>>(); 87 if left.len() != right.len() { 88 return false; 89 } 90 for (a, b) in left.into_iter().zip(right) { 91 if TokenTreeHelper(&a) != TokenTreeHelper(&b) { 92 return false; 93 } 94 } 95 true 96 } 97 } 98 99 impl<'a> Hash for TokenStreamHelper<'a> { hash<H: Hasher>(&self, state: &mut H)100 fn hash<H: Hasher>(&self, state: &mut H) { 101 let tts = self.0.clone().into_iter().collect::<Vec<_>>(); 102 tts.len().hash(state); 103 for tt in tts { 104 TokenTreeHelper(&tt).hash(state); 105 } 106 } 107 } 108