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
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
use super::*;
use crate::punctuated::Punctuated;

ast_struct! {
    /// An enum variant.
    ///
    /// *This type is available only if Syn is built with the `"derive"` or `"full"`
    /// feature.*
    pub struct Variant {
        /// Attributes tagged on the variant.
        pub attrs: Vec<Attribute>,

        /// Name of the variant.
        pub ident: Ident,

        /// Content stored in the variant.
        pub fields: Fields,

        /// Explicit discriminant: `Variant = 1`
        pub discriminant: Option<(Token![=], Expr)>,
    }
}

ast_enum_of_structs! {
    /// Data stored within an enum variant or struct.
    ///
    /// *This type is available only if Syn is built with the `"derive"` or `"full"`
    /// feature.*
    ///
    /// # Syntax tree enum
    ///
    /// This type is a [syntax tree enum].
    ///
    /// [syntax tree enum]: enum.Expr.html#syntax-tree-enums
    //
    // TODO: change syntax-tree-enum link to an intra rustdoc link, currently
    // blocked on https://github.com/rust-lang/rust/issues/62833
    pub enum Fields {
        /// Named fields of a struct or struct variant such as `Point { x: f64,
        /// y: f64 }`.
        Named(FieldsNamed),

        /// Unnamed fields of a tuple struct or tuple variant such as `Some(T)`.
        Unnamed(FieldsUnnamed),

        /// Unit struct or unit variant such as `None`.
        Unit,
    }
}

ast_struct! {
    /// Named fields of a struct or struct variant such as `Point { x: f64,
    /// y: f64 }`.
    ///
    /// *This type is available only if Syn is built with the `"derive"` or
    /// `"full"` feature.*
    pub struct FieldsNamed {
        pub brace_token: token::Brace,
        pub named: Punctuated<Field, Token![,]>,
    }
}

ast_struct! {
    /// Unnamed fields of a tuple struct or tuple variant such as `Some(T)`.
    ///
    /// *This type is available only if Syn is built with the `"derive"` or
    /// `"full"` feature.*
    pub struct FieldsUnnamed {
        pub paren_token: token::Paren,
        pub unnamed: Punctuated<Field, Token![,]>,
    }
}

impl Fields {
    /// Get an iterator over the borrowed [`Field`] items in this object. This
    /// iterator can be used to iterate over a named or unnamed struct or
    /// variant's fields uniformly.
    pub fn iter(&self) -> punctuated::Iter<Field> {
        match self {
            Fields::Unit => crate::punctuated::empty_punctuated_iter(),
            Fields::Named(f) => f.named.iter(),
            Fields::Unnamed(f) => f.unnamed.iter(),
        }
    }

    /// Get an iterator over the mutably borrowed [`Field`] items in this
    /// object. This iterator can be used to iterate over a named or unnamed
    /// struct or variant's fields uniformly.
    pub fn iter_mut(&mut self) -> punctuated::IterMut<Field> {
        match self {
            Fields::Unit => crate::punctuated::empty_punctuated_iter_mut(),
            Fields::Named(f) => f.named.iter_mut(),
            Fields::Unnamed(f) => f.unnamed.iter_mut(),
        }
    }

    /// Returns the number of fields.
    pub fn len(&self) -> usize {
        match self {
            Fields::Unit => 0,
            Fields::Named(f) => f.named.len(),
            Fields::Unnamed(f) => f.unnamed.len(),
        }
    }

    /// Returns `true` if there are zero fields.
    pub fn is_empty(&self) -> bool {
        match self {
            Fields::Unit => true,
            Fields::Named(f) => f.named.is_empty(),
            Fields::Unnamed(f) => f.unnamed.is_empty(),
        }
    }
}

impl IntoIterator for Fields {
    type Item = Field;
    type IntoIter = punctuated::IntoIter<Field>;

    fn into_iter(self) -> Self::IntoIter {
        match self {
            Fields::Unit => Punctuated::<Field, ()>::new().into_iter(),
            Fields::Named(f) => f.named.into_iter(),
            Fields::Unnamed(f) => f.unnamed.into_iter(),
        }
    }
}

impl<'a> IntoIterator for &'a Fields {
    type Item = &'a Field;
    type IntoIter = punctuated::Iter<'a, Field>;

    fn into_iter(self) -> Self::IntoIter {
        self.iter()
    }
}

impl<'a> IntoIterator for &'a mut Fields {
    type Item = &'a mut Field;
    type IntoIter = punctuated::IterMut<'a, Field>;

    fn into_iter(self) -> Self::IntoIter {
        self.iter_mut()
    }
}

ast_struct! {
    /// A field of a struct or enum variant.
    ///
    /// *This type is available only if Syn is built with the `"derive"` or `"full"`
    /// feature.*
    pub struct Field {
        /// Attributes tagged on the field.
        pub attrs: Vec<Attribute>,

        /// Visibility of the field.
        pub vis: Visibility,

        /// Name of the field, if any.
        ///
        /// Fields of tuple structs have no names.
        pub ident: Option<Ident>,

        pub colon_token: Option<Token![:]>,

        /// Type of the field.
        pub ty: Type,
    }
}

ast_enum_of_structs! {
    /// The visibility level of an item: inherited or `pub` or
    /// `pub(restricted)`.
    ///
    /// *This type is available only if Syn is built with the `"derive"` or `"full"`
    /// feature.*
    ///
    /// # Syntax tree enum
    ///
    /// This type is a [syntax tree enum].
    ///
    /// [syntax tree enum]: enum.Expr.html#syntax-tree-enums
    //
    // TODO: change syntax-tree-enum link to an intra rustdoc link, currently
    // blocked on https://github.com/rust-lang/rust/issues/62833
    pub enum Visibility {
        /// A public visibility level: `pub`.
        Public(VisPublic),

        /// A crate-level visibility: `crate`.
        Crate(VisCrate),

        /// A visibility level restricted to some path: `pub(self)` or
        /// `pub(super)` or `pub(crate)` or `pub(in some::module)`.
        Restricted(VisRestricted),

        /// An inherited visibility, which usually means private.
        Inherited,
    }
}

ast_struct! {
    /// A public visibility level: `pub`.
    ///
    /// *This type is available only if Syn is built with the `"derive"` or
    /// `"full"` feature.*
    pub struct VisPublic {
        pub pub_token: Token![pub],
    }
}

ast_struct! {
    /// A crate-level visibility: `crate`.
    ///
    /// *This type is available only if Syn is built with the `"derive"` or
    /// `"full"` feature.*
    pub struct VisCrate {
        pub crate_token: Token![crate],
    }
}

ast_struct! {
    /// A visibility level restricted to some path: `pub(self)` or
    /// `pub(super)` or `pub(crate)` or `pub(in some::module)`.
    ///
    /// *This type is available only if Syn is built with the `"derive"` or
    /// `"full"` feature.*
    pub struct VisRestricted {
        pub pub_token: Token![pub],
        pub paren_token: token::Paren,
        pub in_token: Option<Token![in]>,
        pub path: Box<Path>,
    }
}

#[cfg(feature = "parsing")]
pub mod parsing {
    use super::*;
    use crate::ext::IdentExt;
    use crate::parse::discouraged::Speculative;
    use crate::parse::{Parse, ParseStream, Result};

    impl Parse for Variant {
        fn parse(input: ParseStream) -> Result<Self> {
            let attrs = input.call(Attribute::parse_outer)?;
            let _visibility: Visibility = input.parse()?;
            Ok(Variant {
                attrs,
                ident: input.parse()?,
                fields: {
                    if input.peek(token::Brace) {
                        Fields::Named(input.parse()?)
                    } else if input.peek(token::Paren) {
                        Fields::Unnamed(input.parse()?)
                    } else {
                        Fields::Unit
                    }
                },
                discriminant: {
                    if input.peek(Token![=]) {
                        let eq_token: Token![=] = input.parse()?;
                        let discriminant: Expr = input.parse()?;
                        Some((eq_token, discriminant))
                    } else {
                        None
                    }
                },
            })
        }
    }

    impl Parse for FieldsNamed {
        fn parse(input: ParseStream) -> Result<Self> {
            let content;
            Ok(FieldsNamed {
                brace_token: braced!(content in input),
                named: content.parse_terminated(Field::parse_named)?,
            })
        }
    }

    impl Parse for FieldsUnnamed {
        fn parse(input: ParseStream) -> Result<Self> {
            let content;
            Ok(FieldsUnnamed {
                paren_token: parenthesized!(content in input),
                unnamed: content.parse_terminated(Field::parse_unnamed)?,
            })
        }
    }

    impl Field {
        /// Parses a named (braced struct) field.
        pub fn parse_named(input: ParseStream) -> Result<Self> {
            Ok(Field {
                attrs: input.call(Attribute::parse_outer)?,
                vis: input.parse()?,
                ident: Some(input.parse()?),
                colon_token: Some(input.parse()?),
                ty: input.parse()?,
            })
        }

        /// Parses an unnamed (tuple struct) field.
        pub fn parse_unnamed(input: ParseStream) -> Result<Self> {
            Ok(Field {
                attrs: input.call(Attribute::parse_outer)?,
                vis: input.parse()?,
                ident: None,
                colon_token: None,
                ty: input.parse()?,
            })
        }
    }

    impl Parse for Visibility {
        fn parse(input: ParseStream) -> Result<Self> {
            // Recognize an empty None-delimited group, as produced by a $:vis
            // matcher that matched no tokens.
            if input.peek(token::Group) {
                let ahead = input.fork();
                let group = crate::group::parse_group(&ahead)?;
                if group.content.is_empty() {
                    input.advance_to(&ahead);
                    return Ok(Visibility::Inherited);
                }
            }

            if input.peek(Token![pub]) {
                Self::parse_pub(input)
            } else if input.peek(Token![crate]) {
                Self::parse_crate(input)
            } else {
                Ok(Visibility::Inherited)
            }
        }
    }

    impl Visibility {
        fn parse_pub(input: ParseStream) -> Result<Self> {
            let pub_token = input.parse::<Token![pub]>()?;

            if input.peek(token::Paren) {
                let ahead = input.fork();

                let content;
                let paren_token = parenthesized!(content in ahead);
                if content.peek(Token![crate])
                    || content.peek(Token![self])
                    || content.peek(Token![super])
                {
                    let path = content.call(Ident::parse_any)?;

                    // Ensure there are no additional tokens within `content`.
                    // Without explicitly checking, we may misinterpret a tuple
                    // field as a restricted visibility, causing a parse error.
                    // e.g. `pub (crate::A, crate::B)` (Issue #720).
                    if content.is_empty() {
                        input.advance_to(&ahead);
                        return Ok(Visibility::Restricted(VisRestricted {
                            pub_token,
                            paren_token,
                            in_token: None,
                            path: Box::new(Path::from(path)),
                        }));
                    }
                } else if content.peek(Token![in]) {
                    let in_token: Token![in] = content.parse()?;
                    let path = content.call(Path::parse_mod_style)?;

                    input.advance_to(&ahead);
                    return Ok(Visibility::Restricted(VisRestricted {
                        pub_token,
                        paren_token,
                        in_token: Some(in_token),
                        path: Box::new(path),
                    }));
                }
            }

            Ok(Visibility::Public(VisPublic { pub_token }))
        }

        fn parse_crate(input: ParseStream) -> Result<Self> {
            if input.peek2(Token![::]) {
                Ok(Visibility::Inherited)
            } else {
                Ok(Visibility::Crate(VisCrate {
                    crate_token: input.parse()?,
                }))
            }
        }

        #[cfg(feature = "full")]
        pub(crate) fn is_some(&self) -> bool {
            match self {
                Visibility::Inherited => false,
                _ => true,
            }
        }
    }
}

#[cfg(feature = "printing")]
mod printing {
    use super::*;
    use crate::print::TokensOrDefault;
    use proc_macro2::TokenStream;
    use quote::{ToTokens, TokenStreamExt};

    impl ToTokens for Variant {
        fn to_tokens(&self, tokens: &mut TokenStream) {
            tokens.append_all(&self.attrs);
            self.ident.to_tokens(tokens);
            self.fields.to_tokens(tokens);
            if let Some((eq_token, disc)) = &self.discriminant {
                eq_token.to_tokens(tokens);
                disc.to_tokens(tokens);
            }
        }
    }

    impl ToTokens for FieldsNamed {
        fn to_tokens(&self, tokens: &mut TokenStream) {
            self.brace_token.surround(tokens, |tokens| {
                self.named.to_tokens(tokens);
            });
        }
    }

    impl ToTokens for FieldsUnnamed {
        fn to_tokens(&self, tokens: &mut TokenStream) {
            self.paren_token.surround(tokens, |tokens| {
                self.unnamed.to_tokens(tokens);
            });
        }
    }

    impl ToTokens for Field {
        fn to_tokens(&self, tokens: &mut TokenStream) {
            tokens.append_all(&self.attrs);
            self.vis.to_tokens(tokens);
            if let Some(ident) = &self.ident {
                ident.to_tokens(tokens);
                TokensOrDefault(&self.colon_token).to_tokens(tokens);
            }
            self.ty.to_tokens(tokens);
        }
    }

    impl ToTokens for VisPublic {
        fn to_tokens(&self, tokens: &mut TokenStream) {
            self.pub_token.to_tokens(tokens)
        }
    }

    impl ToTokens for VisCrate {
        fn to_tokens(&self, tokens: &mut TokenStream) {
            self.crate_token.to_tokens(tokens);
        }
    }

    impl ToTokens for VisRestricted {
        fn to_tokens(&self, tokens: &mut TokenStream) {
            self.pub_token.to_tokens(tokens);
            self.paren_token.surround(tokens, |tokens| {
                // TODO: If we have a path which is not "self" or "super" or
                // "crate", automatically add the "in" token.
                self.in_token.to_tokens(tokens);
                self.path.to_tokens(tokens);
            });
        }
    }
}