Trait GenericParamExt

pub trait GenericParamExt {
    type TypeParam;
    type LifetimeParam;
    type ConstParam;

    // Provided methods
    fn as_type_param(&self) -> Option<&Self::TypeParam> { ... }
    fn as_lifetime_param(&self) -> Option<&Self::LifetimeParam> { ... }
    fn as_const_param(&self) -> Option<&Self::ConstParam> { ... }
}

Extension trait for GenericParam to support getting values by variant.

Usage

darling::ast::Generics needs a way to test its params array in order to iterate over type params. Rather than require callers to use darling::ast::GenericParam in all cases, this trait makes that polymorphic.

Required Associated Types

type TypeParam

The type this GenericParam uses to represent type params and their bounds

type LifetimeParam

type ConstParam

Provided Methods

fn as_type_param(&self) -> Option<&Self::TypeParam>

If this GenericParam is a type param, get the underlying value.

fn as_lifetime_param(&self) -> Option<&Self::LifetimeParam>

If this GenericParam is a lifetime, get the underlying value.

fn as_const_param(&self) -> Option<&Self::ConstParam>

If this GenericParam is a const param, get the underlying value.

Implementations on Foreign Types

impl GenericParamExt for GenericParam

type TypeParam = TypeParam

type LifetimeParam = LifetimeParam

type ConstParam = ConstParam

fn as_type_param(&self) -> Option<&<GenericParam as GenericParamExt>::TypeParam>

fn as_lifetime_param( &self, ) -> Option<&<GenericParam as GenericParamExt>::LifetimeParam>

fn as_const_param( &self, ) -> Option<&<GenericParam as GenericParamExt>::ConstParam>

impl GenericParamExt for TypeParam

type TypeParam = TypeParam

type LifetimeParam = ()

type ConstParam = ()

fn as_type_param(&self) -> Option<&<TypeParam as GenericParamExt>::TypeParam>

Implementors

impl<T, L, C> GenericParamExt for darling::ast::GenericParam<T, L, C>

type TypeParam = T

type LifetimeParam = L

type ConstParam = C