use crate::attr::Attribute;
use crate::data::{Fields, FieldsNamed, Variant};
use crate::generics::Generics;
use crate::ident::Ident;
use crate::punctuated::Punctuated;
use crate::restriction::Visibility;
use crate::token;
ast_struct! {
/// Data structure sent to a `proc_macro_derive` macro.
#[cfg_attr(docsrs, doc(cfg(feature = "derive")))]
pub struct DeriveInput {
pub attrs: Vec<Attribute>,
pub vis: Visibility,
pub ident: Ident,
pub generics: Generics,
pub data: Data,
}
}
ast_enum! {
/// The storage of a struct, enum or union data structure.
///
/// # Syntax tree enum
///
/// This type is a [syntax tree enum].
///
/// [syntax tree enum]: crate::expr::Expr#syntax-tree-enums
#[cfg_attr(docsrs, doc(cfg(feature = "derive")))]
pub enum Data {
Struct(DataStruct),
Enum(DataEnum),
Union(DataUnion),
}
}
ast_struct! {
/// A struct input to a `proc_macro_derive` macro.
#[cfg_attr(docsrs, doc(cfg(feature = "derive")))]
pub struct DataStruct {
pub struct_token: Token![struct],
pub fields: Fields,
pub semi_token: Option<Token![;]>,
}
}
ast_struct! {
/// An enum input to a `proc_macro_derive` macro.
#[cfg_attr(docsrs, doc(cfg(feature = "derive")))]
pub struct DataEnum {
pub enum_token: Token![enum],
pub brace_token: token::Brace,
pub variants: Punctuated<Variant, Token![,]>,
}
}
ast_struct! {
/// An untagged union input to a `proc_macro_derive` macro.
#[cfg_attr(docsrs, doc(cfg(feature = "derive")))]
pub struct DataUnion {
pub union_token: Token![union],
pub fields: FieldsNamed,
}
}
#[cfg(feature = "parsing")]
pub(crate) mod parsing {
use crate::attr::Attribute;
use crate::data::{Fields, FieldsNamed, Variant};
use crate::derive::{Data, DataEnum, DataStruct, DataUnion, DeriveInput};
use crate::error::Result;
use crate::generics::{Generics, WhereClause};
use crate::ident::Ident;
use crate::parse::{Parse, ParseStream};
use crate::punctuated::Punctuated;
use crate::restriction::Visibility;
use crate::token;
#[cfg_attr(docsrs, doc(cfg(feature = "parsing")))]
impl Parse for DeriveInput {
fn parse(input: ParseStream) -> Result<Self> {
let attrs = input.call(Attribute::parse_outer)?;
let vis = input.parse::<Visibility>()?;
let lookahead = input.lookahead1();
if lookahead.peek(Token![struct]) {
let struct_token = input.parse::<Token![struct]>()?;
let ident = input.parse::<Ident>()?;
let generics = input.parse::<Generics>()?;
let (where_clause, fields, semi) = data_struct(input)?;
Ok(DeriveInput {
attrs,
vis,
ident,
generics: Generics {
where_clause,
..generics
},
data: Data::Struct(DataStruct {
struct_token,
fields,
semi_token: semi,
}),
})
} else if lookahead.peek(Token![enum]) {
let enum_token = input.parse::<Token![enum]>()?;
let ident = input.parse::<Ident>()?;
let generics = input.parse::<Generics>()?;
let (where_clause, brace, variants) = data_enum(input)?;
Ok(DeriveInput {
attrs,
vis,
ident,
generics: Generics {
where_clause,
..generics
},
data: Data::Enum(DataEnum {
enum_token,
brace_token: brace,
variants,
}),
})
} else if lookahead.peek(Token![union]) {
let union_token = input.parse::<Token![union]>()?;
let ident = input.parse::<Ident>()?;
let generics = input.parse::<Generics>()?;
let (where_clause, fields) = data_union(input)?;
Ok(DeriveInput {
attrs,
vis,
ident,
generics: Generics {
where_clause,
..generics
},
data: Data::Union(DataUnion {
union_token,
fields,
}),
})
} else {
Err(lookahead.error())
}
}
}
pub(crate) fn data_struct(
input: ParseStream,
) -> Result<(Option<WhereClause>, Fields, Option<Token![;]>)> {
let mut lookahead = input.lookahead1();
let mut where_clause = None;
if lookahead.peek(Token![where]) {
where_clause = Some(input.parse()?);
lookahead = input.lookahead1();
}
if where_clause.is_none() && lookahead.peek(token::Paren) {
let fields = input.parse()?;
lookahead = input.lookahead1();
if lookahead.peek(Token![where]) {
where_clause = Some(input.parse()?);
lookahead = input.lookahead1();
}
if lookahead.peek(Token![;]) {
let semi = input.parse()?;
Ok((where_clause, Fields::Unnamed(fields), Some(semi)))
} else {
Err(lookahead.error())
}
} else if lookahead.peek(token::Brace) {
let fields = input.parse()?;
Ok((where_clause, Fields::Named(fields), None))
} else if lookahead.peek(Token![;]) {
let semi = input.parse()?;
Ok((where_clause, Fields::Unit, Some(semi)))
} else {
Err(lookahead.error())
}
}
pub(crate) fn data_enum(
input: ParseStream,
) -> Result<(
Option<WhereClause>,
token::Brace,
Punctuated<Variant, Token![,]>,
)> {
let where_clause = input.parse()?;
let content;
let brace = braced!(content in input);
let variants = content.parse_terminated(Variant::parse, Token![,])?;
Ok((where_clause, brace, variants))
}
pub(crate) fn data_union(input: ParseStream) -> Result<(Option<WhereClause>, FieldsNamed)> {
let where_clause = input.parse()?;
let fields = input.parse()?;
Ok((where_clause, fields))
}
}
#[cfg(feature = "printing")]
mod printing {
use crate::attr::FilterAttrs;
use crate::data::Fields;
use crate::derive::{Data, DeriveInput};
use crate::print::TokensOrDefault;
use proc_macro2::TokenStream;
use quote::ToTokens;
#[cfg_attr(docsrs, doc(cfg(feature = "printing")))]
impl ToTokens for DeriveInput {
fn to_tokens(&self, tokens: &mut TokenStream) {
for attr in self.attrs.outer() {
attr.to_tokens(tokens);
}
self.vis.to_tokens(tokens);
match &self.data {
Data::Struct(d) => d.struct_token.to_tokens(tokens),
Data::Enum(d) => d.enum_token.to_tokens(tokens),
Data::Union(d) => d.union_token.to_tokens(tokens),
}
self.ident.to_tokens(tokens);
self.generics.to_tokens(tokens);
match &self.data {
Data::Struct(data) => match &data.fields {
Fields::Named(fields) => {
self.generics.where_clause.to_tokens(tokens);
fields.to_tokens(tokens);
}
Fields::Unnamed(fields) => {
fields.to_tokens(tokens);
self.generics.where_clause.to_tokens(tokens);
TokensOrDefault(&data.semi_token).to_tokens(tokens);
}
Fields::Unit => {
self.generics.where_clause.to_tokens(tokens);
TokensOrDefault(&data.semi_token).to_tokens(tokens);
}
},
Data::Enum(data) => {
self.generics.where_clause.to_tokens(tokens);
data.brace_token.surround(tokens, |tokens| {
data.variants.to_tokens(tokens);
});
}
Data::Union(data) => {
self.generics.where_clause.to_tokens(tokens);
data.fields.to_tokens(tokens);
}
}
}
}
}
