1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
#[cfg(feature = "fold")]
pub mod fold {
    use crate::fold::Fold;
    use crate::punctuated::{Pair, Punctuated};
    use proc_macro2::Span;

    pub trait FoldHelper {
        type Item;
        fn lift<F>(self, f: F) -> Self
        where
            F: FnMut(Self::Item) -> Self::Item;
    }

    impl<T> FoldHelper for Vec<T> {
        type Item = T;
        fn lift<F>(self, f: F) -> Self
        where
            F: FnMut(Self::Item) -> Self::Item,
        {
            self.into_iter().map(f).collect()
        }
    }

    impl<T, U> FoldHelper for Punctuated<T, U> {
        type Item = T;
        fn lift<F>(self, mut f: F) -> Self
        where
            F: FnMut(Self::Item) -> Self::Item,
        {
            self.into_pairs()
                .map(Pair::into_tuple)
                .map(|(t, u)| Pair::new(f(t), u))
                .collect()
        }
    }

    pub fn tokens_helper<F: Fold + ?Sized, S: Spans>(folder: &mut F, spans: &S) -> S {
        spans.fold(folder)
    }

    pub trait Spans {
        fn fold<F: Fold + ?Sized>(&self, folder: &mut F) -> Self;
    }

    impl Spans for Span {
        fn fold<F: Fold + ?Sized>(&self, folder: &mut F) -> Self {
            folder.fold_span(*self)
        }
    }

    impl Spans for [Span; 1] {
        fn fold<F: Fold + ?Sized>(&self, folder: &mut F) -> Self {
            [folder.fold_span(self[0])]
        }
    }

    impl Spans for [Span; 2] {
        fn fold<F: Fold + ?Sized>(&self, folder: &mut F) -> Self {
            [folder.fold_span(self[0]), folder.fold_span(self[1])]
        }
    }

    impl Spans for [Span; 3] {
        fn fold<F: Fold + ?Sized>(&self, folder: &mut F) -> Self {
            [
                folder.fold_span(self[0]),
                folder.fold_span(self[1]),
                folder.fold_span(self[2]),
            ]
        }
    }
}

#[cfg(feature = "visit")]
pub mod visit {
    use crate::visit::Visit;
    use proc_macro2::Span;

    pub fn tokens_helper<'ast, V: Visit<'ast> + ?Sized, S: Spans>(visitor: &mut V, spans: &S) {
        spans.visit(visitor);
    }

    pub trait Spans {
        fn visit<'ast, V: Visit<'ast> + ?Sized>(&self, visitor: &mut V);
    }

    impl Spans for Span {
        fn visit<'ast, V: Visit<'ast> + ?Sized>(&self, visitor: &mut V) {
            visitor.visit_span(self);
        }
    }

    impl Spans for [Span; 1] {
        fn visit<'ast, V: Visit<'ast> + ?Sized>(&self, visitor: &mut V) {
            visitor.visit_span(&self[0]);
        }
    }

    impl Spans for [Span; 2] {
        fn visit<'ast, V: Visit<'ast> + ?Sized>(&self, visitor: &mut V) {
            visitor.visit_span(&self[0]);
            visitor.visit_span(&self[1]);
        }
    }

    impl Spans for [Span; 3] {
        fn visit<'ast, V: Visit<'ast> + ?Sized>(&self, visitor: &mut V) {
            visitor.visit_span(&self[0]);
            visitor.visit_span(&self[1]);
            visitor.visit_span(&self[2]);
        }
    }
}

#[cfg(feature = "visit-mut")]
pub mod visit_mut {
    use crate::visit_mut::VisitMut;
    use proc_macro2::Span;

    pub fn tokens_helper<V: VisitMut + ?Sized, S: Spans>(visitor: &mut V, spans: &mut S) {
        spans.visit_mut(visitor);
    }

    pub trait Spans {
        fn visit_mut<V: VisitMut + ?Sized>(&mut self, visitor: &mut V);
    }

    impl Spans for Span {
        fn visit_mut<V: VisitMut + ?Sized>(&mut self, visitor: &mut V) {
            visitor.visit_span_mut(self);
        }
    }

    impl Spans for [Span; 1] {
        fn visit_mut<V: VisitMut + ?Sized>(&mut self, visitor: &mut V) {
            visitor.visit_span_mut(&mut self[0]);
        }
    }

    impl Spans for [Span; 2] {
        fn visit_mut<V: VisitMut + ?Sized>(&mut self, visitor: &mut V) {
            visitor.visit_span_mut(&mut self[0]);
            visitor.visit_span_mut(&mut self[1]);
        }
    }

    impl Spans for [Span; 3] {
        fn visit_mut<V: VisitMut + ?Sized>(&mut self, visitor: &mut V) {
            visitor.visit_span_mut(&mut self[0]);
            visitor.visit_span_mut(&mut self[1]);
            visitor.visit_span_mut(&mut self[2]);
        }
    }
}