use super::*;
use crate::punctuated::Punctuated;
ast_struct! {
/// An enum variant.
///
/// *This type is available 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 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 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 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 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 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 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 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 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::{Parse, ParseStream, Result};
impl Parse for Variant {
fn parse(input: ParseStream) -> Result<Self> {
Ok(Variant {
attrs: input.call(Attribute::parse_outer)?,
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> {
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) {
// TODO: optimize using advance_to
let ahead = input.fork();
let mut content;
parenthesized!(content in ahead);
if content.peek(Token![crate])
|| content.peek(Token![self])
|| content.peek(Token![super])
{
return Ok(Visibility::Restricted(VisRestricted {
pub_token,
paren_token: parenthesized!(content in input),
in_token: None,
path: Box::new(Path::from(content.call(Ident::parse_any)?)),
}));
} else if content.peek(Token![in]) {
return Ok(Visibility::Restricted(VisRestricted {
pub_token,
paren_token: parenthesized!(content in input),
in_token: Some(content.parse()?),
path: Box::new(content.call(Path::parse_mod_style)?),
}));
}
}
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 = "printing")]
mod printing {
use super::*;
use proc_macro2::TokenStream;
use quote::{ToTokens, TokenStreamExt};
use crate::print::TokensOrDefault;
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);
});
}
}
}