[−][src]Trait structural::field::rev_get_field::OptRevIntoFieldRef

pub trait OptRevIntoFieldRef<'a, This>: OptRevIntoField<This> + OptRevGetFieldMut<'a, This> { }

A trait alias for fallible RevIntoFieldImpl + RevGetFieldImpl, generally used to access fields inside enums.

This is the type we are accessing,and Self is a field path.

Example

This example shows how to access an enum field by reference,and by value.

Also,how to write extension traits with Rev* traits.

use structural::field::{OptRevIntoFieldRef,RevGetFieldType};
use structural::for_examples::{StructFoo,WithBoom};
use structural::{StructuralExt,FP,fp};

let nope=StructFoo{ foo: WithBoom::Nope };
let boom=StructFoo{ foo: WithBoom::Boom{  a: "hello", b: &[3,5,8,13]  } };

assert_eq!( nope.get_nested(), None );
assert_eq!( boom.get_nested(), Some(&&[3,5,8,13][..]) );

assert_eq!( nope.into_nested(), None );
assert_eq!( boom.into_nested(), Some(&[3,5,8,13][..]) );

trait GetNested: Sized {
    fn get_nested<'a,Ty>(&'a self)->Option<&'a Ty>
    where
        FP!(foo::Boom.b): OptRevIntoFieldRef<'a,Self,Ty=Ty>
    {
        self.field_(fp!(foo::Boom.b))
    }

    fn into_nested<'a,Ty>(self)->Option<Ty>
    where
        FP!(foo::Boom.b): OptRevIntoFieldRef<'a,Self,Ty=Ty>
    {
        self.into_field(fp!(foo::Boom.b))
    }
}

impl<T> GetNested for T {}

Implementors

impl<'a, Path, This> OptRevIntoFieldRef<'a, This> for Path where
    Path: OptRevIntoField<This> + OptRevGetFieldMut<'a, This>, [src]

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