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-rw-r--r--syn/src/derive.rs273
1 files changed, 273 insertions, 0 deletions
diff --git a/syn/src/derive.rs b/syn/src/derive.rs
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+use super::*;
+use crate::punctuated::Punctuated;
+
+ast_struct! {
+ /// Data structure sent to a `proc_macro_derive` macro.
+ ///
+ /// *This type is available if Syn is built with the `"derive"` feature.*
+ pub struct DeriveInput {
+ /// Attributes tagged on the whole struct or enum.
+ pub attrs: Vec<Attribute>,
+
+ /// Visibility of the struct or enum.
+ pub vis: Visibility,
+
+ /// Name of the struct or enum.
+ pub ident: Ident,
+
+ /// Generics required to complete the definition.
+ pub generics: Generics,
+
+ /// Data within the struct or enum.
+ pub data: Data,
+ }
+}
+
+ast_enum_of_structs! {
+ /// The storage of a struct, enum or union data structure.
+ ///
+ /// *This type is available if Syn is built with the `"derive"` 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 Data {
+ /// A struct input to a `proc_macro_derive` macro.
+ Struct(DataStruct),
+
+ /// An enum input to a `proc_macro_derive` macro.
+ Enum(DataEnum),
+
+ /// An untagged union input to a `proc_macro_derive` macro.
+ Union(DataUnion),
+ }
+
+ do_not_generate_to_tokens
+}
+
+ast_struct! {
+ /// A struct input to a `proc_macro_derive` macro.
+ ///
+ /// *This type is available if Syn is built with the `"derive"`
+ /// feature.*
+ 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.
+ ///
+ /// *This type is available if Syn is built with the `"derive"`
+ /// feature.*
+ 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.
+ ///
+ /// *This type is available if Syn is built with the `"derive"`
+ /// feature.*
+ pub struct DataUnion {
+ pub union_token: Token![union],
+ pub fields: FieldsNamed,
+ }
+}
+
+#[cfg(feature = "parsing")]
+pub mod parsing {
+ use super::*;
+
+ use crate::parse::{Parse, ParseStream, Result};
+
+ 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 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 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)?;
+
+ Ok((where_clause, brace, variants))
+ }
+
+ pub 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 super::*;
+
+ use proc_macro2::TokenStream;
+ use quote::ToTokens;
+
+ use crate::attr::FilterAttrs;
+ use crate::print::TokensOrDefault;
+
+ 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);
+ }
+ }
+ }
+ }
+}
generated by cgit v1.2.1 (git 2.18.0) at 2024-05-19 03:27:46 +0000