syn/
gen_helper.rs

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1#[cfg(feature = "fold")]
2pub mod fold {
3    use crate::fold::Fold;
4    use crate::punctuated::{Pair, Punctuated};
5    use proc_macro2::Span;
6
7    pub trait FoldHelper {
8        type Item;
9        fn lift<F>(self, f: F) -> Self
10        where
11            F: FnMut(Self::Item) -> Self::Item;
12    }
13
14    impl<T> FoldHelper for Vec<T> {
15        type Item = T;
16        fn lift<F>(self, f: F) -> Self
17        where
18            F: FnMut(Self::Item) -> Self::Item,
19        {
20            self.into_iter().map(f).collect()
21        }
22    }
23
24    impl<T, U> FoldHelper for Punctuated<T, U> {
25        type Item = T;
26        fn lift<F>(self, mut f: F) -> Self
27        where
28            F: FnMut(Self::Item) -> Self::Item,
29        {
30            self.into_pairs()
31                .map(Pair::into_tuple)
32                .map(|(t, u)| Pair::new(f(t), u))
33                .collect()
34        }
35    }
36
37    pub fn tokens_helper<F: Fold + ?Sized, S: Spans>(folder: &mut F, spans: &S) -> S {
38        spans.fold(folder)
39    }
40
41    pub trait Spans {
42        fn fold<F: Fold + ?Sized>(&self, folder: &mut F) -> Self;
43    }
44
45    impl Spans for Span {
46        fn fold<F: Fold + ?Sized>(&self, folder: &mut F) -> Self {
47            folder.fold_span(*self)
48        }
49    }
50
51    impl Spans for [Span; 1] {
52        fn fold<F: Fold + ?Sized>(&self, folder: &mut F) -> Self {
53            [folder.fold_span(self[0])]
54        }
55    }
56
57    impl Spans for [Span; 2] {
58        fn fold<F: Fold + ?Sized>(&self, folder: &mut F) -> Self {
59            [folder.fold_span(self[0]), folder.fold_span(self[1])]
60        }
61    }
62
63    impl Spans for [Span; 3] {
64        fn fold<F: Fold + ?Sized>(&self, folder: &mut F) -> Self {
65            [
66                folder.fold_span(self[0]),
67                folder.fold_span(self[1]),
68                folder.fold_span(self[2]),
69            ]
70        }
71    }
72}
73
74#[cfg(feature = "visit")]
75pub mod visit {
76    use crate::visit::Visit;
77    use proc_macro2::Span;
78
79    pub fn tokens_helper<'ast, V: Visit<'ast> + ?Sized, S: Spans>(visitor: &mut V, spans: &S) {
80        spans.visit(visitor);
81    }
82
83    pub trait Spans {
84        fn visit<'ast, V: Visit<'ast> + ?Sized>(&self, visitor: &mut V);
85    }
86
87    impl Spans for Span {
88        fn visit<'ast, V: Visit<'ast> + ?Sized>(&self, visitor: &mut V) {
89            visitor.visit_span(self);
90        }
91    }
92
93    impl Spans for [Span; 1] {
94        fn visit<'ast, V: Visit<'ast> + ?Sized>(&self, visitor: &mut V) {
95            visitor.visit_span(&self[0]);
96        }
97    }
98
99    impl Spans for [Span; 2] {
100        fn visit<'ast, V: Visit<'ast> + ?Sized>(&self, visitor: &mut V) {
101            visitor.visit_span(&self[0]);
102            visitor.visit_span(&self[1]);
103        }
104    }
105
106    impl Spans for [Span; 3] {
107        fn visit<'ast, V: Visit<'ast> + ?Sized>(&self, visitor: &mut V) {
108            visitor.visit_span(&self[0]);
109            visitor.visit_span(&self[1]);
110            visitor.visit_span(&self[2]);
111        }
112    }
113}
114
115#[cfg(feature = "visit-mut")]
116pub mod visit_mut {
117    use crate::visit_mut::VisitMut;
118    use proc_macro2::Span;
119
120    pub fn tokens_helper<V: VisitMut + ?Sized, S: Spans>(visitor: &mut V, spans: &mut S) {
121        spans.visit_mut(visitor);
122    }
123
124    pub trait Spans {
125        fn visit_mut<V: VisitMut + ?Sized>(&mut self, visitor: &mut V);
126    }
127
128    impl Spans for Span {
129        fn visit_mut<V: VisitMut + ?Sized>(&mut self, visitor: &mut V) {
130            visitor.visit_span_mut(self);
131        }
132    }
133
134    impl Spans for [Span; 1] {
135        fn visit_mut<V: VisitMut + ?Sized>(&mut self, visitor: &mut V) {
136            visitor.visit_span_mut(&mut self[0]);
137        }
138    }
139
140    impl Spans for [Span; 2] {
141        fn visit_mut<V: VisitMut + ?Sized>(&mut self, visitor: &mut V) {
142            visitor.visit_span_mut(&mut self[0]);
143            visitor.visit_span_mut(&mut self[1]);
144        }
145    }
146
147    impl Spans for [Span; 3] {
148        fn visit_mut<V: VisitMut + ?Sized>(&mut self, visitor: &mut V) {
149            visitor.visit_span_mut(&mut self[0]);
150            visitor.visit_span_mut(&mut self[1]);
151            visitor.visit_span_mut(&mut self[2]);
152        }
153    }
154}
syn/gen_helper.rs

syn/
gen_helper.rs
