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 type is available if Syn is built with the "derive" or "full" feature.

Fields

lt_token: Option<Lt>

params: Punctuated<GenericParam, Comma>

gt_token: Option<Gt>

where_clause: Option<WhereClause>

Methods

impl Generics

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 lifetimes(&self) -> Lifetimes

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

pub fn lifetimes_mut(&mut self) -> LifetimesMut

Returns an Iterator<Item = &mut LifetimeDef> over the lifetime 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.

# 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.

Trait Implementations

impl Parse for Generics

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

impl Default for Generics

fn default() -> Generics

Returns the "default value" for a type.

impl Clone for Generics

fn clone(&self) -> Generics

Returns a copy of the value.

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

Performs copy-assignment from source.

impl ToTokens for Generics

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

Write self to the given TokenStream.

fn into_token_stream(self) -> TokenStream

Convert self directly into a TokenStream object.