Trait OptRevGetField 

pub trait OptRevGetField<'a, This>: RevGetFieldImpl<'a, This, Err = FailedAccess> { }

A trait alias for a fallible 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 you can access an enum field by reference.

use structural::field::OptRevGetField;
use structural::{StructuralExt,FP,fp};

let tup1=(3,5,(8,(Some(13),21)));
let tup2=(3,5,(8,(None,21)));

assert_eq!( get_nested(&tup1), Some(&13) );
assert_eq!( get_nested(&tup2), None );

fn get_nested<'a,T>(this:&'a T)->Option<&'a i32>
where
    FP!(2.1.0?): OptRevGetField<'a,T,Ty=i32>
{
    this.field_(fp!(2.1.0?))
}

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementors

impl<'a, Path, This> OptRevGetField<'a, This> for Path

where Path: RevGetFieldImpl<'a, This, Err = FailedAccess>,