Struct syn::Generics

pub struct Generics {
    pub lt_token: Option<Lt>,
    pub params: Punctuated<GenericParam, Comma>,
    pub gt_token: Option<Gt>,
    pub where_clause: Option<WhereClause>,
}

Lifetimes and type parameters attached to a declaration of a function, enum, trait, etc.

This struct represents two distinct optional syntactic elements, generic parameters and where clause. In some locations of the grammar, there may be other tokens in between these two things.

Fields

lt_token: Option<Lt>

params: Punctuated<GenericParam, Comma>

gt_token: Option<Gt>

where_clause: Option<WhereClause>

Implementations

impl Generics

pub fn lifetimes(&self) -> Lifetimes<'_>

Returns an Iterator<Item = &LifetimeParam> over the lifetime parameters in self.params.

pub fn lifetimes_mut(&mut self) -> LifetimesMut<'_>

Returns an Iterator<Item = &mut LifetimeParam> over the lifetime parameters in self.params.

pub fn type_params(&self) -> TypeParams<'_>

Returns an Iterator<Item = &TypeParam> over the type parameters in self.params.

pub fn type_params_mut(&mut self) -> TypeParamsMut<'_>

Returns an Iterator<Item = &mut TypeParam> over the type parameters in self.params.

pub fn const_params(&self) -> ConstParams<'_>

Returns an Iterator<Item = &ConstParam> over the constant parameters in self.params.

pub fn const_params_mut(&mut self) -> ConstParamsMut<'_>

Returns an Iterator<Item = &mut ConstParam> over the constant parameters in self.params.

pub fn make_where_clause(&mut self) -> &mut WhereClause

Initializes an empty where-clause if there is not one present already.

impl Generics

pub fn split_for_impl( &self, ) -> (ImplGenerics<'_>, TypeGenerics<'_>, Option<&WhereClause>)

Split a type’s generics into the pieces required for impl’ing a trait for that type.

let (impl_generics, ty_generics, where_clause) = generics.split_for_impl();
quote! {
    impl #impl_generics MyTrait for #name #ty_generics #where_clause {
        // ...
    }
}

Trait Implementations

impl Clone for Generics

fn clone(&self) -> Self

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Default for Generics

fn default() -> Self

Returns the “default value” for a type.

impl Parse for Generics

fn parse(input: ParseStream<'_>) -> Result<Self>

impl ToTokens for Generics

fn to_tokens(&self, tokens: &mut TokenStream)

Write self to the given TokenStream.

fn to_token_stream(&self) -> TokenStream

Convert self directly into a TokenStream object.

fn into_token_stream(self) -> TokenStream

where Self: Sized,

Convert self directly into a TokenStream object.