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
155
156

#![cfg_attr(feature = "nightly-testing", plugin(clippy))]
#![cfg_attr(feature = "nightly-testing", feature(plugin))]
#![cfg_attr(not(feature = "with-syntex"), feature(rustc_private, plugin))]

#[cfg(feature = "with-syntex")]
#[macro_use]
extern crate syntex_syntax as syntax;

#[cfg(not(feature = "with-syntex"))]
#[macro_use]
extern crate syntax;

use syntax::ast;
use syntax::codemap;
use syntax::ext::base::ExtCtxt;
use syntax::ptr::P;

pub mod attr;

mod error;
pub use error::Error;

pub struct Item<'a> {
    pub ident: ast::Ident,
    pub span: codemap::Span,
    pub attrs: attr::Item,
    pub body: Body<'a>,
    pub generics: &'a ast::Generics,
}

pub enum Body<'a> {
    Enum(Vec<Variant<'a>>),
    Struct(Style, Vec<Field<'a>>),
}

pub struct Variant<'a> {
    pub ident: ast::Ident,
    pub span: codemap::Span,
    pub attrs: attr::Variant,
    pub style: Style,
    pub fields: Vec<Field<'a>>,
}

pub struct Field<'a> {
    pub ident: Option<ast::Ident>,
    pub span: codemap::Span,
    pub attrs: attr::Field,
    pub ty: &'a P<ast::Ty>,
}

pub enum Style {
    Struct,
    Tuple,
    Newtype,
    Unit,
}

impl<'a> Item<'a> {
    pub fn from_ast(
        cx: &ExtCtxt,
        item: &'a ast::Item,
    ) -> Result<Item<'a>, Error> {
        let attrs = attr::Item::from_ast(cx, item);

        let (body, generics) = match item.node {
            ast::ItemKind::Enum(ref enum_def, ref generics) => {
                let variants = enum_from_ast(cx, enum_def);
                (Body::Enum(variants), generics)
            }
            ast::ItemKind::Struct(ref variant_data, ref generics) => {
                let (style, fields) = struct_from_ast(cx, variant_data);
                (Body::Struct(style, fields), generics)
            }
            _ => {
                return Err(Error::UnexpectedItemKind);
            }
        };

        Ok(Item {
            ident: item.ident,
            span: item.span,
            attrs: attrs,
            body: body,
            generics: generics,
        })
    }
}

impl<'a> Body<'a> {
    pub fn all_fields(&'a self) -> Box<Iterator<Item=&'a Field<'a>> + 'a> {
        match *self {
            Body::Enum(ref variants) => {
                Box::new(variants.iter()
                             .flat_map(|variant| variant.fields.iter()))
            }
            Body::Struct(_, ref fields) => {
                Box::new(fields.iter())
            }
        }
    }
}

fn enum_from_ast<'a>(
    cx: &ExtCtxt,
    enum_def: &'a ast::EnumDef,
) -> Vec<Variant<'a>> {
    enum_def.variants.iter()
        .map(|variant| {
            let (style, fields) = struct_from_ast(cx, &variant.node.data);
            Variant {
                ident: variant.node.name,
                span: variant.span,
                attrs: attr::Variant::from_ast(cx, variant),
                style: style,
                fields: fields,
            }
        })
        .collect()
}

fn struct_from_ast<'a>(
    cx: &ExtCtxt,
    variant_data: &'a ast::VariantData,
) -> (Style, Vec<Field<'a>>) {
    match *variant_data {
        ast::VariantData::Struct(ref fields, _) => {
            (Style::Struct, fields_from_ast(cx, fields))
        }
        ast::VariantData::Tuple(ref fields, _) if fields.len() == 1 => {
            (Style::Newtype, fields_from_ast(cx, fields))
        }
        ast::VariantData::Tuple(ref fields, _) => {
            (Style::Tuple, fields_from_ast(cx, fields))
        }
        ast::VariantData::Unit(_) => {
            (Style::Unit, Vec::new())
        }
    }
}

fn fields_from_ast<'a>(
    cx: &ExtCtxt,
    fields: &'a [ast::StructField],
) -> Vec<Field<'a>> {
    fields.iter()
        .enumerate()
        .map(|(i, field)| {
            Field {
                ident: field.ident,
                span: field.span,
                attrs: attr::Field::from_ast(cx, i, field),
                ty: &field.ty,
            }
        })
        .collect()
}