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

use super::*;

/// Doc-comments are promoted to attributes that have `is_sugared_doc` = true
#[derive(Debug, Clone, Eq, PartialEq)]
pub struct Attribute {
    pub value: MetaItem,
    pub is_sugared_doc: bool,
}

/// A compile-time attribute item.
///
/// E.g. `#[test]`, `#[derive(..)]` or `#[feature = "foo"]`
#[derive(Debug, Clone, Eq, PartialEq)]
pub enum MetaItem {
    /// Word meta item.
    ///
    /// E.g. `test` as in `#[test]`
    Word(Ident),
    /// List meta item.
    ///
    /// E.g. `derive(..)` as in `#[derive(..)]`
    List(Ident, Vec<MetaItem>),
    /// Name value meta item.
    ///
    /// E.g. `feature = "foo"` as in `#[feature = "foo"]`
    NameValue(Ident, Lit),
}

impl MetaItem {
    pub fn name(&self) -> &str {
        match *self {
            MetaItem::Word(ref name) => name.as_ref(),
            MetaItem::List(ref name, _) => name.as_ref(),
            MetaItem::NameValue(ref name, _) => name.as_ref(),
        }
    }
}

#[cfg(feature = "parsing")]
pub mod parsing {
    use super::*;
    use ident::parsing::ident;
    use lit::{Lit, StrStyle};
    use lit::parsing::lit;
    use nom::multispace;

    named!(pub attribute -> Attribute, alt!(
        do_parse!(
            punct!("#") >>
            punct!("[") >>
            meta_item: meta_item >>
            punct!("]") >>
            (Attribute {
                value: meta_item,
                is_sugared_doc: false,
            })
        )
        |
        do_parse!(
            punct!("///") >>
            space: multispace >>
            content: take_until!("\n") >>
            (Attribute {
                value: MetaItem::NameValue(
                    "doc".into(),
                    Lit::Str(
                        format!("///{}{}", space, content),
                        StrStyle::Cooked,
                    ),
                ),
                is_sugared_doc: true,
            })
        )
    ));

    named!(meta_item -> MetaItem, alt!(
        do_parse!(
            id: ident >>
            punct!("(") >>
            inner: separated_list!(punct!(","), meta_item) >>
            punct!(")") >>
            (MetaItem::List(id, inner))
        )
        |
        do_parse!(
            name: ident >>
            punct!("=") >>
            value: lit >>
            (MetaItem::NameValue(name, value))
        )
        |
        map!(ident, MetaItem::Word)
    ));
}

#[cfg(feature = "printing")]
mod printing {
    use super::*;
    use quote::{Tokens, ToTokens};

    impl ToTokens for Attribute {
        fn to_tokens(&self, tokens: &mut Tokens) {
            tokens.append("#");
            tokens.append("[");
            self.value.to_tokens(tokens);
            tokens.append("]");
        }
    }

    impl ToTokens for MetaItem {
        fn to_tokens(&self, tokens: &mut Tokens) {
            match *self {
                MetaItem::Word(ref ident) => {
                    ident.to_tokens(tokens);
                }
                MetaItem::List(ref ident, ref inner) => {
                    ident.to_tokens(tokens);
                    tokens.append("(");
                    tokens.append_separated(inner, ",");
                    tokens.append(")");
                }
                MetaItem::NameValue(ref name, ref value) => {
                    name.to_tokens(tokens);
                    tokens.append("=");
                    value.to_tokens(tokens);
                }
            }
        }
    }
}