| use super::*; |
| use punctuated::{Iter, IterMut, Punctuated}; |
| |
| ast_struct! { |
| /// Lifetimes and type parameters attached to a declaration of a function, |
| /// enum, trait, etc. |
| /// |
| /// *This type is available if Syn is built with the `"derive"` or `"full"` |
| /// feature.* |
| #[derive(Default)] |
| pub struct Generics { |
| pub lt_token: Option<Token![<]>, |
| pub params: Punctuated<GenericParam, Token![,]>, |
| pub gt_token: Option<Token![>]>, |
| pub where_clause: Option<WhereClause>, |
| } |
| } |
| |
| ast_enum_of_structs! { |
| /// A generic type parameter, lifetime, or const generic: `T: Into<String>`, |
| /// `'a: 'b`, `const LEN: usize`. |
| /// |
| /// *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 GenericParam { |
| /// A generic type parameter: `T: Into<String>`. |
| /// |
| /// *This type is available if Syn is built with the `"derive"` or |
| /// `"full"` feature.* |
| pub Type(TypeParam { |
| pub attrs: Vec<Attribute>, |
| pub ident: Ident, |
| pub colon_token: Option<Token![:]>, |
| pub bounds: Punctuated<TypeParamBound, Token![+]>, |
| pub eq_token: Option<Token![=]>, |
| pub default: Option<Type>, |
| }), |
| |
| /// A lifetime definition: `'a: 'b + 'c + 'd`. |
| /// |
| /// *This type is available if Syn is built with the `"derive"` or |
| /// `"full"` feature.* |
| pub Lifetime(LifetimeDef { |
| pub attrs: Vec<Attribute>, |
| pub lifetime: Lifetime, |
| pub colon_token: Option<Token![:]>, |
| pub bounds: Punctuated<Lifetime, Token![+]>, |
| }), |
| |
| /// A const generic parameter: `const LENGTH: usize`. |
| /// |
| /// *This type is available if Syn is built with the `"derive"` or |
| /// `"full"` feature.* |
| pub Const(ConstParam { |
| pub attrs: Vec<Attribute>, |
| pub const_token: Token![const], |
| pub ident: Ident, |
| pub colon_token: Token![:], |
| pub ty: Type, |
| pub eq_token: Option<Token![=]>, |
| pub default: Option<Expr>, |
| }), |
| } |
| } |
| |
| impl Generics { |
| /// Returns an |
| /// <code |
| /// style="padding-right:0;">Iterator<Item = &</code><a |
| /// href="struct.TypeParam.html"><code |
| /// style="padding-left:0;padding-right:0;">TypeParam</code></a><code |
| /// style="padding-left:0;">></code> |
| /// over the type parameters in `self.params`. |
| pub fn type_params(&self) -> TypeParams { |
| TypeParams(self.params.iter()) |
| } |
| |
| /// Returns an |
| /// <code |
| /// style="padding-right:0;">Iterator<Item = &mut </code><a |
| /// href="struct.TypeParam.html"><code |
| /// style="padding-left:0;padding-right:0;">TypeParam</code></a><code |
| /// style="padding-left:0;">></code> |
| /// over the type parameters in `self.params`. |
| pub fn type_params_mut(&mut self) -> TypeParamsMut { |
| TypeParamsMut(self.params.iter_mut()) |
| } |
| |
| /// Returns an |
| /// <code |
| /// style="padding-right:0;">Iterator<Item = &</code><a |
| /// href="struct.LifetimeDef.html"><code |
| /// style="padding-left:0;padding-right:0;">LifetimeDef</code></a><code |
| /// style="padding-left:0;">></code> |
| /// over the lifetime parameters in `self.params`. |
| pub fn lifetimes(&self) -> Lifetimes { |
| Lifetimes(self.params.iter()) |
| } |
| |
| /// Returns an |
| /// <code |
| /// style="padding-right:0;">Iterator<Item = &mut </code><a |
| /// href="struct.LifetimeDef.html"><code |
| /// style="padding-left:0;padding-right:0;">LifetimeDef</code></a><code |
| /// style="padding-left:0;">></code> |
| /// over the lifetime parameters in `self.params`. |
| pub fn lifetimes_mut(&mut self) -> LifetimesMut { |
| LifetimesMut(self.params.iter_mut()) |
| } |
| |
| /// Returns an |
| /// <code |
| /// style="padding-right:0;">Iterator<Item = &</code><a |
| /// href="struct.ConstParam.html"><code |
| /// style="padding-left:0;padding-right:0;">ConstParam</code></a><code |
| /// style="padding-left:0;">></code> |
| /// over the constant parameters in `self.params`. |
| pub fn const_params(&self) -> ConstParams { |
| ConstParams(self.params.iter()) |
| } |
| |
| /// Returns an |
| /// <code |
| /// style="padding-right:0;">Iterator<Item = &mut </code><a |
| /// href="struct.ConstParam.html"><code |
| /// style="padding-left:0;padding-right:0;">ConstParam</code></a><code |
| /// style="padding-left:0;">></code> |
| /// over the constant parameters in `self.params`. |
| pub fn const_params_mut(&mut self) -> ConstParamsMut { |
| ConstParamsMut(self.params.iter_mut()) |
| } |
| |
| /// Initializes an empty `where`-clause if there is not one present already. |
| pub fn make_where_clause(&mut self) -> &mut WhereClause { |
| // This is Option::get_or_insert_with in Rust 1.20. |
| if self.where_clause.is_none() { |
| self.where_clause = Some(WhereClause { |
| where_token: <Token![where]>::default(), |
| predicates: Punctuated::new(), |
| }); |
| } |
| match self.where_clause { |
| Some(ref mut where_clause) => where_clause, |
| None => unreachable!(), |
| } |
| } |
| } |
| |
| pub struct TypeParams<'a>(Iter<'a, GenericParam>); |
| |
| impl<'a> Iterator for TypeParams<'a> { |
| type Item = &'a TypeParam; |
| |
| fn next(&mut self) -> Option<Self::Item> { |
| let next = match self.0.next() { |
| Some(item) => item, |
| None => return None, |
| }; |
| if let GenericParam::Type(ref type_param) = *next { |
| Some(type_param) |
| } else { |
| self.next() |
| } |
| } |
| } |
| |
| pub struct TypeParamsMut<'a>(IterMut<'a, GenericParam>); |
| |
| impl<'a> Iterator for TypeParamsMut<'a> { |
| type Item = &'a mut TypeParam; |
| |
| fn next(&mut self) -> Option<Self::Item> { |
| let next = match self.0.next() { |
| Some(item) => item, |
| None => return None, |
| }; |
| if let GenericParam::Type(ref mut type_param) = *next { |
| Some(type_param) |
| } else { |
| self.next() |
| } |
| } |
| } |
| |
| pub struct Lifetimes<'a>(Iter<'a, GenericParam>); |
| |
| impl<'a> Iterator for Lifetimes<'a> { |
| type Item = &'a LifetimeDef; |
| |
| fn next(&mut self) -> Option<Self::Item> { |
| let next = match self.0.next() { |
| Some(item) => item, |
| None => return None, |
| }; |
| if let GenericParam::Lifetime(ref lifetime) = *next { |
| Some(lifetime) |
| } else { |
| self.next() |
| } |
| } |
| } |
| |
| pub struct LifetimesMut<'a>(IterMut<'a, GenericParam>); |
| |
| impl<'a> Iterator for LifetimesMut<'a> { |
| type Item = &'a mut LifetimeDef; |
| |
| fn next(&mut self) -> Option<Self::Item> { |
| let next = match self.0.next() { |
| Some(item) => item, |
| None => return None, |
| }; |
| if let GenericParam::Lifetime(ref mut lifetime) = *next { |
| Some(lifetime) |
| } else { |
| self.next() |
| } |
| } |
| } |
| |
| pub struct ConstParams<'a>(Iter<'a, GenericParam>); |
| |
| impl<'a> Iterator for ConstParams<'a> { |
| type Item = &'a ConstParam; |
| |
| fn next(&mut self) -> Option<Self::Item> { |
| let next = match self.0.next() { |
| Some(item) => item, |
| None => return None, |
| }; |
| if let GenericParam::Const(ref const_param) = *next { |
| Some(const_param) |
| } else { |
| self.next() |
| } |
| } |
| } |
| |
| pub struct ConstParamsMut<'a>(IterMut<'a, GenericParam>); |
| |
| impl<'a> Iterator for ConstParamsMut<'a> { |
| type Item = &'a mut ConstParam; |
| |
| fn next(&mut self) -> Option<Self::Item> { |
| let next = match self.0.next() { |
| Some(item) => item, |
| None => return None, |
| }; |
| if let GenericParam::Const(ref mut const_param) = *next { |
| Some(const_param) |
| } else { |
| self.next() |
| } |
| } |
| } |
| |
| /// Returned by `Generics::split_for_impl`. |
| /// |
| /// *This type is available if Syn is built with the `"derive"` or `"full"` |
| /// feature and the `"printing"` feature.* |
| #[cfg(feature = "printing")] |
| #[cfg_attr(feature = "extra-traits", derive(Debug, Eq, PartialEq, Hash))] |
| #[cfg_attr(feature = "clone-impls", derive(Clone))] |
| pub struct ImplGenerics<'a>(&'a Generics); |
| |
| /// Returned by `Generics::split_for_impl`. |
| /// |
| /// *This type is available if Syn is built with the `"derive"` or `"full"` |
| /// feature and the `"printing"` feature.* |
| #[cfg(feature = "printing")] |
| #[cfg_attr(feature = "extra-traits", derive(Debug, Eq, PartialEq, Hash))] |
| #[cfg_attr(feature = "clone-impls", derive(Clone))] |
| pub struct TypeGenerics<'a>(&'a Generics); |
| |
| /// Returned by `TypeGenerics::as_turbofish`. |
| /// |
| /// *This type is available if Syn is built with the `"derive"` or `"full"` |
| /// feature and the `"printing"` feature.* |
| #[cfg(feature = "printing")] |
| #[cfg_attr(feature = "extra-traits", derive(Debug, Eq, PartialEq, Hash))] |
| #[cfg_attr(feature = "clone-impls", derive(Clone))] |
| pub struct Turbofish<'a>(&'a Generics); |
| |
| #[cfg(feature = "printing")] |
| impl Generics { |
| /// Split a type's generics into the pieces required for impl'ing a trait |
| /// for that type. |
| /// |
| /// ```edition2018 |
| /// # use proc_macro2::{Span, Ident}; |
| /// # use quote::quote; |
| /// # |
| /// # fn main() { |
| /// # let generics: syn::Generics = Default::default(); |
| /// # let name = Ident::new("MyType", Span::call_site()); |
| /// # |
| /// let (impl_generics, ty_generics, where_clause) = generics.split_for_impl(); |
| /// quote! { |
| /// impl #impl_generics MyTrait for #name #ty_generics #where_clause { |
| /// // ... |
| /// } |
| /// } |
| /// # ; |
| /// # } |
| /// ``` |
| /// |
| /// *This method is available if Syn is built with the `"derive"` or |
| /// `"full"` feature and the `"printing"` feature.* |
| pub fn split_for_impl(&self) -> (ImplGenerics, TypeGenerics, Option<&WhereClause>) { |
| ( |
| ImplGenerics(self), |
| TypeGenerics(self), |
| self.where_clause.as_ref(), |
| ) |
| } |
| } |
| |
| #[cfg(feature = "printing")] |
| impl<'a> TypeGenerics<'a> { |
| /// Turn a type's generics like `<X, Y>` into a turbofish like `::<X, Y>`. |
| /// |
| /// *This method is available if Syn is built with the `"derive"` or |
| /// `"full"` feature and the `"printing"` feature.* |
| pub fn as_turbofish(&self) -> Turbofish { |
| Turbofish(self.0) |
| } |
| } |
| |
| ast_struct! { |
| /// A set of bound lifetimes: `for<'a, 'b, 'c>`. |
| /// |
| /// *This type is available if Syn is built with the `"derive"` or `"full"` |
| /// feature.* |
| #[derive(Default)] |
| pub struct BoundLifetimes { |
| pub for_token: Token![for], |
| pub lt_token: Token![<], |
| pub lifetimes: Punctuated<LifetimeDef, Token![,]>, |
| pub gt_token: Token![>], |
| } |
| } |
| |
| impl LifetimeDef { |
| pub fn new(lifetime: Lifetime) -> Self { |
| LifetimeDef { |
| attrs: Vec::new(), |
| lifetime: lifetime, |
| colon_token: None, |
| bounds: Punctuated::new(), |
| } |
| } |
| } |
| |
| impl From<Ident> for TypeParam { |
| fn from(ident: Ident) -> Self { |
| TypeParam { |
| attrs: vec![], |
| ident: ident, |
| colon_token: None, |
| bounds: Punctuated::new(), |
| eq_token: None, |
| default: None, |
| } |
| } |
| } |
| |
| ast_enum_of_structs! { |
| /// A trait or lifetime used as a bound on a type parameter. |
| /// |
| /// *This type is available if Syn is built with the `"derive"` or `"full"` |
| /// feature.* |
| pub enum TypeParamBound { |
| pub Trait(TraitBound), |
| pub Lifetime(Lifetime), |
| } |
| } |
| |
| ast_struct! { |
| /// A trait used as a bound on a type parameter. |
| /// |
| /// *This type is available if Syn is built with the `"derive"` or `"full"` |
| /// feature.* |
| pub struct TraitBound { |
| pub paren_token: Option<token::Paren>, |
| pub modifier: TraitBoundModifier, |
| /// The `for<'a>` in `for<'a> Foo<&'a T>` |
| pub lifetimes: Option<BoundLifetimes>, |
| /// The `Foo<&'a T>` in `for<'a> Foo<&'a T>` |
| pub path: Path, |
| } |
| } |
| |
| ast_enum! { |
| /// A modifier on a trait bound, currently only used for the `?` in |
| /// `?Sized`. |
| /// |
| /// *This type is available if Syn is built with the `"derive"` or `"full"` |
| /// feature.* |
| #[cfg_attr(feature = "clone-impls", derive(Copy))] |
| pub enum TraitBoundModifier { |
| None, |
| Maybe(Token![?]), |
| } |
| } |
| |
| ast_struct! { |
| /// A `where` clause in a definition: `where T: Deserialize<'de>, D: |
| /// 'static`. |
| /// |
| /// *This type is available if Syn is built with the `"derive"` or `"full"` |
| /// feature.* |
| pub struct WhereClause { |
| pub where_token: Token![where], |
| pub predicates: Punctuated<WherePredicate, Token![,]>, |
| } |
| } |
| |
| ast_enum_of_structs! { |
| /// A single predicate in a `where` clause: `T: Deserialize<'de>`. |
| /// |
| /// *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 WherePredicate { |
| /// A type predicate in a `where` clause: `for<'c> Foo<'c>: Trait<'c>`. |
| /// |
| /// *This type is available if Syn is built with the `"derive"` or |
| /// `"full"` feature.* |
| pub Type(PredicateType { |
| /// Any lifetimes from a `for` binding |
| pub lifetimes: Option<BoundLifetimes>, |
| /// The type being bounded |
| pub bounded_ty: Type, |
| pub colon_token: Token![:], |
| /// Trait and lifetime bounds (`Clone+Send+'static`) |
| pub bounds: Punctuated<TypeParamBound, Token![+]>, |
| }), |
| |
| /// A lifetime predicate in a `where` clause: `'a: 'b + 'c`. |
| /// |
| /// *This type is available if Syn is built with the `"derive"` or |
| /// `"full"` feature.* |
| pub Lifetime(PredicateLifetime { |
| pub lifetime: Lifetime, |
| pub colon_token: Token![:], |
| pub bounds: Punctuated<Lifetime, Token![+]>, |
| }), |
| |
| /// An equality predicate in a `where` clause (unsupported). |
| /// |
| /// *This type is available if Syn is built with the `"derive"` or |
| /// `"full"` feature.* |
| pub Eq(PredicateEq { |
| pub lhs_ty: Type, |
| pub eq_token: Token![=], |
| pub rhs_ty: Type, |
| }), |
| } |
| } |
| |
| #[cfg(feature = "parsing")] |
| pub mod parsing { |
| use super::*; |
| |
| use parse::{Parse, ParseStream, Result}; |
| |
| impl Parse for Generics { |
| fn parse(input: ParseStream) -> Result<Self> { |
| if !input.peek(Token![<]) { |
| return Ok(Generics::default()); |
| } |
| |
| let lt_token: Token![<] = input.parse()?; |
| |
| let mut params = Punctuated::new(); |
| let mut allow_lifetime_param = true; |
| let mut allow_type_param = true; |
| loop { |
| if input.peek(Token![>]) { |
| break; |
| } |
| |
| let attrs = input.call(Attribute::parse_outer)?; |
| let lookahead = input.lookahead1(); |
| if allow_lifetime_param && lookahead.peek(Lifetime) { |
| params.push_value(GenericParam::Lifetime(LifetimeDef { |
| attrs: attrs, |
| ..input.parse()? |
| })); |
| } else if allow_type_param && lookahead.peek(Ident) { |
| allow_lifetime_param = false; |
| params.push_value(GenericParam::Type(TypeParam { |
| attrs: attrs, |
| ..input.parse()? |
| })); |
| } else if lookahead.peek(Token![const]) { |
| allow_lifetime_param = false; |
| allow_type_param = false; |
| params.push_value(GenericParam::Const(ConstParam { |
| attrs: attrs, |
| ..input.parse()? |
| })); |
| } else { |
| return Err(lookahead.error()); |
| } |
| |
| if input.peek(Token![>]) { |
| break; |
| } |
| let punct = input.parse()?; |
| params.push_punct(punct); |
| } |
| |
| let gt_token: Token![>] = input.parse()?; |
| |
| Ok(Generics { |
| lt_token: Some(lt_token), |
| params: params, |
| gt_token: Some(gt_token), |
| where_clause: None, |
| }) |
| } |
| } |
| |
| impl Parse for GenericParam { |
| fn parse(input: ParseStream) -> Result<Self> { |
| let attrs = input.call(Attribute::parse_outer)?; |
| |
| let lookahead = input.lookahead1(); |
| if lookahead.peek(Ident) { |
| Ok(GenericParam::Type(TypeParam { |
| attrs: attrs, |
| ..input.parse()? |
| })) |
| } else if lookahead.peek(Lifetime) { |
| Ok(GenericParam::Lifetime(LifetimeDef { |
| attrs: attrs, |
| ..input.parse()? |
| })) |
| } else if lookahead.peek(Token![const]) { |
| Ok(GenericParam::Const(ConstParam { |
| attrs: attrs, |
| ..input.parse()? |
| })) |
| } else { |
| Err(lookahead.error()) |
| } |
| } |
| } |
| |
| impl Parse for LifetimeDef { |
| fn parse(input: ParseStream) -> Result<Self> { |
| let has_colon; |
| Ok(LifetimeDef { |
| attrs: input.call(Attribute::parse_outer)?, |
| lifetime: input.parse()?, |
| colon_token: { |
| if input.peek(Token![:]) { |
| has_colon = true; |
| Some(input.parse()?) |
| } else { |
| has_colon = false; |
| None |
| } |
| }, |
| bounds: { |
| let mut bounds = Punctuated::new(); |
| if has_colon { |
| loop { |
| if input.peek(Token![,]) || input.peek(Token![>]) { |
| break; |
| } |
| let value = input.parse()?; |
| bounds.push_value(value); |
| if !input.peek(Token![+]) { |
| break; |
| } |
| let punct = input.parse()?; |
| bounds.push_punct(punct); |
| } |
| } |
| bounds |
| }, |
| }) |
| } |
| } |
| |
| impl Parse for BoundLifetimes { |
| fn parse(input: ParseStream) -> Result<Self> { |
| Ok(BoundLifetimes { |
| for_token: input.parse()?, |
| lt_token: input.parse()?, |
| lifetimes: { |
| let mut lifetimes = Punctuated::new(); |
| while !input.peek(Token![>]) { |
| lifetimes.push_value(input.parse()?); |
| if input.peek(Token![>]) { |
| break; |
| } |
| lifetimes.push_punct(input.parse()?); |
| } |
| lifetimes |
| }, |
| gt_token: input.parse()?, |
| }) |
| } |
| } |
| |
| impl Parse for Option<BoundLifetimes> { |
| fn parse(input: ParseStream) -> Result<Self> { |
| if input.peek(Token![for]) { |
| input.parse().map(Some) |
| } else { |
| Ok(None) |
| } |
| } |
| } |
| |
| impl Parse for TypeParam { |
| fn parse(input: ParseStream) -> Result<Self> { |
| let has_colon; |
| let has_default; |
| Ok(TypeParam { |
| attrs: input.call(Attribute::parse_outer)?, |
| ident: input.parse()?, |
| colon_token: { |
| if input.peek(Token![:]) { |
| has_colon = true; |
| Some(input.parse()?) |
| } else { |
| has_colon = false; |
| None |
| } |
| }, |
| bounds: { |
| let mut bounds = Punctuated::new(); |
| if has_colon { |
| loop { |
| if input.peek(Token![,]) |
| || input.peek(Token![>]) |
| || input.peek(Token![=]) |
| { |
| break; |
| } |
| let value = input.parse()?; |
| bounds.push_value(value); |
| if !input.peek(Token![+]) { |
| break; |
| } |
| let punct = input.parse()?; |
| bounds.push_punct(punct); |
| } |
| } |
| bounds |
| }, |
| eq_token: { |
| if input.peek(Token![=]) { |
| has_default = true; |
| Some(input.parse()?) |
| } else { |
| has_default = false; |
| None |
| } |
| }, |
| default: { |
| if has_default { |
| Some(input.parse()?) |
| } else { |
| None |
| } |
| }, |
| }) |
| } |
| } |
| |
| impl Parse for TypeParamBound { |
| fn parse(input: ParseStream) -> Result<Self> { |
| if input.peek(Lifetime) { |
| return input.parse().map(TypeParamBound::Lifetime); |
| } |
| |
| if input.peek(token::Paren) { |
| let content; |
| let paren_token = parenthesized!(content in input); |
| let mut bound: TraitBound = content.parse()?; |
| bound.paren_token = Some(paren_token); |
| return Ok(TypeParamBound::Trait(bound)); |
| } |
| |
| input.parse().map(TypeParamBound::Trait) |
| } |
| } |
| |
| impl Parse for TraitBound { |
| fn parse(input: ParseStream) -> Result<Self> { |
| let modifier: TraitBoundModifier = input.parse()?; |
| let lifetimes: Option<BoundLifetimes> = input.parse()?; |
| |
| let mut path: Path = input.parse()?; |
| if path.segments.last().unwrap().value().arguments.is_empty() |
| && input.peek(token::Paren) |
| { |
| let parenthesized = PathArguments::Parenthesized(input.parse()?); |
| path.segments.last_mut().unwrap().value_mut().arguments = parenthesized; |
| } |
| |
| Ok(TraitBound { |
| paren_token: None, |
| modifier: modifier, |
| lifetimes: lifetimes, |
| path: path, |
| }) |
| } |
| } |
| |
| impl Parse for TraitBoundModifier { |
| fn parse(input: ParseStream) -> Result<Self> { |
| if input.peek(Token![?]) { |
| input.parse().map(TraitBoundModifier::Maybe) |
| } else { |
| Ok(TraitBoundModifier::None) |
| } |
| } |
| } |
| |
| impl Parse for ConstParam { |
| fn parse(input: ParseStream) -> Result<Self> { |
| let mut default = None; |
| Ok(ConstParam { |
| attrs: input.call(Attribute::parse_outer)?, |
| const_token: input.parse()?, |
| ident: input.parse()?, |
| colon_token: input.parse()?, |
| ty: input.parse()?, |
| eq_token: { |
| if input.peek(Token![=]) { |
| let eq_token = input.parse()?; |
| default = Some(input.parse::<Expr>()?); |
| Some(eq_token) |
| } else { |
| None |
| } |
| }, |
| default: default, |
| }) |
| } |
| } |
| |
| impl Parse for WhereClause { |
| fn parse(input: ParseStream) -> Result<Self> { |
| Ok(WhereClause { |
| where_token: input.parse()?, |
| predicates: { |
| let mut predicates = Punctuated::new(); |
| loop { |
| if input.is_empty() |
| || input.peek(token::Brace) |
| || input.peek(Token![,]) |
| || input.peek(Token![;]) |
| || input.peek(Token![:]) && !input.peek(Token![::]) |
| || input.peek(Token![=]) |
| { |
| break; |
| } |
| let value = input.parse()?; |
| predicates.push_value(value); |
| if !input.peek(Token![,]) { |
| break; |
| } |
| let punct = input.parse()?; |
| predicates.push_punct(punct); |
| } |
| predicates |
| }, |
| }) |
| } |
| } |
| |
| impl Parse for Option<WhereClause> { |
| fn parse(input: ParseStream) -> Result<Self> { |
| if input.peek(Token![where]) { |
| input.parse().map(Some) |
| } else { |
| Ok(None) |
| } |
| } |
| } |
| |
| impl Parse for WherePredicate { |
| fn parse(input: ParseStream) -> Result<Self> { |
| if input.peek(Lifetime) && input.peek2(Token![:]) { |
| Ok(WherePredicate::Lifetime(PredicateLifetime { |
| lifetime: input.parse()?, |
| colon_token: input.parse()?, |
| bounds: { |
| let mut bounds = Punctuated::new(); |
| loop { |
| if input.is_empty() |
| || input.peek(token::Brace) |
| || input.peek(Token![,]) |
| || input.peek(Token![;]) |
| || input.peek(Token![:]) |
| || input.peek(Token![=]) |
| { |
| break; |
| } |
| let value = input.parse()?; |
| bounds.push_value(value); |
| if !input.peek(Token![+]) { |
| break; |
| } |
| let punct = input.parse()?; |
| bounds.push_punct(punct); |
| } |
| bounds |
| }, |
| })) |
| } else { |
| Ok(WherePredicate::Type(PredicateType { |
| lifetimes: input.parse()?, |
| bounded_ty: input.parse()?, |
| colon_token: input.parse()?, |
| bounds: { |
| let mut bounds = Punctuated::new(); |
| loop { |
| if input.is_empty() |
| || input.peek(token::Brace) |
| || input.peek(Token![,]) |
| || input.peek(Token![;]) |
| || input.peek(Token![:]) && !input.peek(Token![::]) |
| || input.peek(Token![=]) |
| { |
| break; |
| } |
| let value = input.parse()?; |
| bounds.push_value(value); |
| if !input.peek(Token![+]) { |
| break; |
| } |
| let punct = input.parse()?; |
| bounds.push_punct(punct); |
| } |
| bounds |
| }, |
| })) |
| } |
| } |
| } |
| } |
| |
| #[cfg(feature = "printing")] |
| mod printing { |
| use super::*; |
| |
| use proc_macro2::TokenStream; |
| use quote::{ToTokens, TokenStreamExt}; |
| |
| use attr::FilterAttrs; |
| use print::TokensOrDefault; |
| |
| impl ToTokens for Generics { |
| fn to_tokens(&self, tokens: &mut TokenStream) { |
| if self.params.is_empty() { |
| return; |
| } |
| |
| TokensOrDefault(&self.lt_token).to_tokens(tokens); |
| |
| // Print lifetimes before types and consts, regardless of their |
| // order in self.params. |
| // |
| // TODO: ordering rules for const parameters vs type parameters have |
| // not been settled yet. https://github.com/rust-lang/rust/issues/44580 |
| let mut trailing_or_empty = true; |
| for param in self.params.pairs() { |
| if let GenericParam::Lifetime(_) = **param.value() { |
| param.to_tokens(tokens); |
| trailing_or_empty = param.punct().is_some(); |
| } |
| } |
| for param in self.params.pairs() { |
| match **param.value() { |
| GenericParam::Type(_) | GenericParam::Const(_) => { |
| if !trailing_or_empty { |
| <Token![,]>::default().to_tokens(tokens); |
| trailing_or_empty = true; |
| } |
| param.to_tokens(tokens); |
| } |
| GenericParam::Lifetime(_) => {} |
| } |
| } |
| |
| TokensOrDefault(&self.gt_token).to_tokens(tokens); |
| } |
| } |
| |
| impl<'a> ToTokens for ImplGenerics<'a> { |
| fn to_tokens(&self, tokens: &mut TokenStream) { |
| if self.0.params.is_empty() { |
| return; |
| } |
| |
| TokensOrDefault(&self.0.lt_token).to_tokens(tokens); |
| |
| // Print lifetimes before types and consts, regardless of their |
| // order in self.params. |
| // |
| // TODO: ordering rules for const parameters vs type parameters have |
| // not been settled yet. https://github.com/rust-lang/rust/issues/44580 |
| let mut trailing_or_empty = true; |
| for param in self.0.params.pairs() { |
| if let GenericParam::Lifetime(_) = **param.value() { |
| param.to_tokens(tokens); |
| trailing_or_empty = param.punct().is_some(); |
| } |
| } |
| for param in self.0.params.pairs() { |
| if let GenericParam::Lifetime(_) = **param.value() { |
| continue; |
| } |
| if !trailing_or_empty { |
| <Token![,]>::default().to_tokens(tokens); |
| trailing_or_empty = true; |
| } |
| match **param.value() { |
| GenericParam::Lifetime(_) => unreachable!(), |
| GenericParam::Type(ref param) => { |
| // Leave off the type parameter defaults |
| tokens.append_all(param.attrs.outer()); |
| param.ident.to_tokens(tokens); |
| if !param.bounds.is_empty() { |
| TokensOrDefault(¶m.colon_token).to_tokens(tokens); |
| param.bounds.to_tokens(tokens); |
| } |
| } |
| GenericParam::Const(ref param) => { |
| // Leave off the const parameter defaults |
| tokens.append_all(param.attrs.outer()); |
| param.const_token.to_tokens(tokens); |
| param.ident.to_tokens(tokens); |
| param.colon_token.to_tokens(tokens); |
| param.ty.to_tokens(tokens); |
| } |
| } |
| param.punct().to_tokens(tokens); |
| } |
| |
| TokensOrDefault(&self.0.gt_token).to_tokens(tokens); |
| } |
| } |
| |
| impl<'a> ToTokens for TypeGenerics<'a> { |
| fn to_tokens(&self, tokens: &mut TokenStream) { |
| if self.0.params.is_empty() { |
| return; |
| } |
| |
| TokensOrDefault(&self.0.lt_token).to_tokens(tokens); |
| |
| // Print lifetimes before types and consts, regardless of their |
| // order in self.params. |
| // |
| // TODO: ordering rules for const parameters vs type parameters have |
| // not been settled yet. https://github.com/rust-lang/rust/issues/44580 |
| let mut trailing_or_empty = true; |
| for param in self.0.params.pairs() { |
| if let GenericParam::Lifetime(ref def) = **param.value() { |
| // Leave off the lifetime bounds and attributes |
| def.lifetime.to_tokens(tokens); |
| param.punct().to_tokens(tokens); |
| trailing_or_empty = param.punct().is_some(); |
| } |
| } |
| for param in self.0.params.pairs() { |
| if let GenericParam::Lifetime(_) = **param.value() { |
| continue; |
| } |
| if !trailing_or_empty { |
| <Token![,]>::default().to_tokens(tokens); |
| trailing_or_empty = true; |
| } |
| match **param.value() { |
| GenericParam::Lifetime(_) => unreachable!(), |
| GenericParam::Type(ref param) => { |
| // Leave off the type parameter defaults |
| param.ident.to_tokens(tokens); |
| } |
| GenericParam::Const(ref param) => { |
| // Leave off the const parameter defaults |
| param.ident.to_tokens(tokens); |
| } |
| } |
| param.punct().to_tokens(tokens); |
| } |
| |
| TokensOrDefault(&self.0.gt_token).to_tokens(tokens); |
| } |
| } |
| |
| impl<'a> ToTokens for Turbofish<'a> { |
| fn to_tokens(&self, tokens: &mut TokenStream) { |
| if !self.0.params.is_empty() { |
| <Token![::]>::default().to_tokens(tokens); |
| TypeGenerics(self.0).to_tokens(tokens); |
| } |
| } |
| } |
| |
| impl ToTokens for BoundLifetimes { |
| fn to_tokens(&self, tokens: &mut TokenStream) { |
| self.for_token.to_tokens(tokens); |
| self.lt_token.to_tokens(tokens); |
| self.lifetimes.to_tokens(tokens); |
| self.gt_token.to_tokens(tokens); |
| } |
| } |
| |
| impl ToTokens for LifetimeDef { |
| fn to_tokens(&self, tokens: &mut TokenStream) { |
| tokens.append_all(self.attrs.outer()); |
| self.lifetime.to_tokens(tokens); |
| if !self.bounds.is_empty() { |
| TokensOrDefault(&self.colon_token).to_tokens(tokens); |
| self.bounds.to_tokens(tokens); |
| } |
| } |
| } |
| |
| impl ToTokens for TypeParam { |
| fn to_tokens(&self, tokens: &mut TokenStream) { |
| tokens.append_all(self.attrs.outer()); |
| self.ident.to_tokens(tokens); |
| if !self.bounds.is_empty() { |
| TokensOrDefault(&self.colon_token).to_tokens(tokens); |
| self.bounds.to_tokens(tokens); |
| } |
| if self.default.is_some() { |
| TokensOrDefault(&self.eq_token).to_tokens(tokens); |
| self.default.to_tokens(tokens); |
| } |
| } |
| } |
| |
| impl ToTokens for TraitBound { |
| fn to_tokens(&self, tokens: &mut TokenStream) { |
| let to_tokens = |tokens: &mut TokenStream| { |
| self.modifier.to_tokens(tokens); |
| self.lifetimes.to_tokens(tokens); |
| self.path.to_tokens(tokens); |
| }; |
| match self.paren_token { |
| Some(ref paren) => paren.surround(tokens, to_tokens), |
| None => to_tokens(tokens), |
| } |
| } |
| } |
| |
| impl ToTokens for TraitBoundModifier { |
| fn to_tokens(&self, tokens: &mut TokenStream) { |
| match *self { |
| TraitBoundModifier::None => {} |
| TraitBoundModifier::Maybe(ref t) => t.to_tokens(tokens), |
| } |
| } |
| } |
| |
| impl ToTokens for ConstParam { |
| fn to_tokens(&self, tokens: &mut TokenStream) { |
| tokens.append_all(self.attrs.outer()); |
| self.const_token.to_tokens(tokens); |
| self.ident.to_tokens(tokens); |
| self.colon_token.to_tokens(tokens); |
| self.ty.to_tokens(tokens); |
| if self.default.is_some() { |
| TokensOrDefault(&self.eq_token).to_tokens(tokens); |
| self.default.to_tokens(tokens); |
| } |
| } |
| } |
| |
| impl ToTokens for WhereClause { |
| fn to_tokens(&self, tokens: &mut TokenStream) { |
| if !self.predicates.is_empty() { |
| self.where_token.to_tokens(tokens); |
| self.predicates.to_tokens(tokens); |
| } |
| } |
| } |
| |
| impl ToTokens for PredicateType { |
| fn to_tokens(&self, tokens: &mut TokenStream) { |
| self.lifetimes.to_tokens(tokens); |
| self.bounded_ty.to_tokens(tokens); |
| self.colon_token.to_tokens(tokens); |
| self.bounds.to_tokens(tokens); |
| } |
| } |
| |
| impl ToTokens for PredicateLifetime { |
| fn to_tokens(&self, tokens: &mut TokenStream) { |
| self.lifetime.to_tokens(tokens); |
| self.colon_token.to_tokens(tokens); |
| self.bounds.to_tokens(tokens); |
| } |
| } |
| |
| impl ToTokens for PredicateEq { |
| fn to_tokens(&self, tokens: &mut TokenStream) { |
| self.lhs_ty.to_tokens(tokens); |
| self.eq_token.to_tokens(tokens); |
| self.rhs_ty.to_tokens(tokens); |
| } |
| } |
| } |
