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>,
}

Available on crate features full or derive only.

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>)

Available on crate feature printing only.

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

Available on crate feature clone-impls only.

fn clone(&self) -> Self

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for Generics

Available on crate feature extra-traits only.

fn fmt(&self, formatter: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for Generics

fn default() -> Self

Returns the “default value” for a type.

impl Hash for Generics

Available on crate feature extra-traits only.

fn hash<H>(&self, state: &mut H)where H: Hasher,

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl Parse for Generics

Available on crate feature parsing only.

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

impl PartialEq<Generics> for Generics

Available on crate feature extra-traits only.

fn eq(&self, other: &Self) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl ToTokens for Generics

Available on crate feature printing only.

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) -> TokenStreamwhere Self: Sized,

Convert self directly into a TokenStream object.

impl Eq for Generics

Available on crate feature extra-traits only.