[−][src]Trait structural::StructuralExt

pub trait StructuralExt {
    fn field_<'a, P>(
        &'a self, 
        path: P
    ) -> NormalizeFieldsOut<Result<&'a P::Ty, P::Err>>
    where
        P: RevGetFieldImpl<'a, Self>,
        Result<&'a P::Ty, P::Err>: NormalizeFields,
    { ... }

    fn fields<'a, P>(&'a self, path: P) -> RevGetMultiFieldOut<'a, P, Self>
    where
        P: RevGetMultiField<'a, Self>,
    { ... }

    fn cloned_fields<'a, P>(
        &'a self, 
        path: P
    ) -> ClonedOut<RevGetMultiFieldOut<'a, P, Self>>
    where
        P: RevGetMultiField<'a, Self>,
        RevGetMultiFieldOut<'a, P, Self>: Cloned,
    { ... }

    fn field_mut<'a, P>(
        &'a mut self, 
        path: P
    ) -> NormalizeFieldsOut<Result<&'a mut P::Ty, P::Err>>
    where
        P: RevGetFieldMutImpl<'a, Self>,
        Result<&'a mut P::Ty, P::Err>: NormalizeFields,
    { ... }

    fn fields_mut<'a, P>(
        &'a mut self, 
        path: P
    ) -> RevGetMultiFieldMutOut<'a, P, Self>
    where
        P: RevGetMultiFieldMut<'a, Self>,
    { ... }

    fn into_field<P>(self, path: P) -> NormalizeFieldsOut<Result<P::Ty, P::Err>>
    where
        P: RevIntoFieldImpl<Self>,
        P::Ty: Sized,
        Result<P::Ty, P::Err>: NormalizeFields,
        Self: Sized,
    { ... }

    fn into_fields<P>(self, path: P) -> RevIntoMultiFieldOut<P, Self>
    where
        P: RevIntoMultiField<Self>,
        Self: Sized,
    { ... }

    fn is_variant<P>(&self, _path: P) -> bool
    where
        P: IsTStr,
        Self: IsVariant<P>,
    { ... }

    fn into_struc<U>(self) -> U
    where
        Self: IntoStructural<U>,
    { ... }

    fn try_into_struc<U>(self) -> Result<U, TryFromError<Self, Self::Error>>
    where
        Self: TryIntoStructural<U>,
    { ... }
}

A trait defining the primary way to call methods from structural traits.

For a wrapper type that defines inherent methods equivalent to the ones in this trait, you can use the StrucWrapper wrapper type.

Provided methods

fn field_<'a, P>(
    &'a self,
    path: P
) -> NormalizeFieldsOut<Result<&'a P::Ty, P::Err>> where
    P: RevGetFieldImpl<'a, Self>,
    Result<&'a P::Ty, P::Err>: NormalizeFields, 

Gets a reference to a field,determined by path.

This is named field_ instead of field because field collides with the DebugTuple/DebugStruct method

Example

use structural::{StructuralExt,fp,structural_alias};

structural_alias!{
    trait EvenFields<A,B,C>{
        0:A,
        2:B,
        4:C,
    }
}

fn with_even<T>(this:&T)
where
    T:EvenFields<u32,u32,u32>
{
    assert_eq!( this.field_(fp!(0)), &1 );
    assert_eq!( this.field_(fp!(2)), &2 );
    assert_eq!( this.field_(fp!(4)), &5 );
}

fn main(){
    with_even( &(1,0,2,0,5) );
    with_even( &(1,0,2,0,5,0) );
    with_even( &(1,0,2,0,5,0,0) );
    with_even( &(1,0,2,0,5,0,0,0) );
}

Enum Example

use structural::{StructuralExt,Structural,fp};

with_circle( &Shape::Circle{ x:3, y:5, radius:8 } );
with_circle( &MoreShapes::Circle{ x:3, y:5, radius:8 } );

fn with_circle<T>(circle:&T)
where
    // `Shape_SI` was generated for Shape by the `Structural` derive.
    T: Shape_SI
{
    assert_eq!( circle.field_(fp!(::Circle.x)), Some(&3) );
    assert_eq!( circle.field_(fp!(::Circle.y)), Some(&5) );
    assert_eq!( circle.field_(fp!(::Circle.radius)), Some(&8) );

    // Constructing the variant proxy is the only Option we have to handle here,
    // instead of every access to the fields in the Circle variant being optional.
    //
    // For a more ergonomic alternative,
    // you can look at the example for the `fields` method
    let proxy=circle.field_(fp!(::Circle)).expect("Expected a circle");
    assert_eq!( proxy.field_(fp!(x)), &3 );
    assert_eq!( proxy.field_(fp!(y)), &5 );
    assert_eq!( proxy.field_(fp!(radius)), &8 );
}

#[derive(Structural)]
enum Shape{
    Circle{x:u32,y:u32,radius:u32},
    Square{x:u32,y:u32,width:u32},
}

#[derive(Structural)]
enum MoreShapes{
    Circle{x:u32,y:u32,radius:u32},
    Square{x:u32,y:u32,width:u32},
    Rectangle{x:u32,y:u32,width:u32,height:u32},
}

fn fields<'a, P>(&'a self, path: P) -> RevGetMultiFieldOut<'a, P, Self> where
    P: RevGetMultiField<'a, Self>, 

Gets references to multiple fields,determined by path.

Access many fields

If you pass a path that references over 8 fields,this will return a tuple of tuples(each nested tuple with 8 elements) instead of a singly nested tuple.

For examples accessing over 8 field look at the docs for the field_pat macro

Example

use structural::{StructuralExt,fp,structural_alias};

structural_alias!{
    trait OddFields<A,B,C>{
        1:A,
        3:B,
        5:C,
    }
}

fn with_even(this:&impl OddFields<u32,u32,u32>){
    assert_eq!( this.fields(fp!(1,3,5)), (&22,&44,&77) );
}

fn main(){
    with_even( &(0,22,0,44,0,77) );
    with_even( &(0,22,0,44,0,77,0) );
    with_even( &(0,22,0,44,0,77,0,0) );
    with_even( &(0,22,0,44,0,77,0,0,0) );
}

Enum Example

use structural::{StructuralExt,Structural,fp};

with_car( &Vehicle::Car{ name:"initial-c", km:9001 } );
with_car( &MoreVehicles::Car{ name:"initial-c", km:9001 } );

fn with_car<T>(car:&T)
where
    // `Vehicle_SI` was generated for Vehicle by the `Structural` derive.
    T: Vehicle_SI
{
    assert_eq!(
        car.fields(fp!(::Car.name, ::Car.km)),
        ( Some(&"initial-c"), Some(&9001) )
    );

    // You can use `=>` to access multiple fields inside of a nested field(or a variant)
    // this allows accessing multiple fields inside an enum variant without having to
    // create an intermediate variant proxy
    // (look at the next assert for what that looks like).
    assert_eq!( car.fields(fp!(::Car=>name,km)), Some((&"initial-c",&9001)) );

    assert_eq!(
        // This is equivalent to the field access in the previous assert
        car.field_(fp!(::Car)).map(|vp| vp.fields(fp!(name,km)) ),
        Some((&"initial-c",&9001))
    );

    assert_eq!( car.cloned_fields(fp!(::Truck=>weight_kg,driven_km)), None);
}

#[derive(Structural)]
enum Vehicle{
    Car{name: &'static str, km:u32},
    Truck{ weight_kg:u32, driven_km:u32 },
}

#[derive(Structural)]
enum MoreVehicles{
    Car{name: &'static str, km:u32},
    Truck{ weight_kg:u32, driven_km:u32 },
    Boat,
}

fn cloned_fields<'a, P>(
    &'a self,
    path: P
) -> ClonedOut<RevGetMultiFieldOut<'a, P, Self>> where
    P: RevGetMultiField<'a, Self>,
    RevGetMultiFieldOut<'a, P, Self>: Cloned, 

Gets clones of multiple fields,determined by path.

Access many fields

If you pass a path that references over 8 fields,this will return a tuple of tuples(each nested tuple with 8 elements) instead of a singly nested tuple.

For examples accessing over 8 field look at the docs for the field_pat macro

Example

This example also uses the reexported IntoArray trait, which allows converting homogeneous tuples to arrays, in this case it's used to iterate over the fields.

use structural::{StructuralExt,Structural,fp,make_struct};
use structural::reexports::IntoArray;

// The `Fruits_SI` trait was declared by the `Structural` derive on `Fruits`.
fn total_fruit_count(fruits:&dyn Fruits_SI)->u32{
    fruits
        .cloned_fields(fp!( apples, oranges, tangerines, tomatoes ))
        .into_array()
        .iter()
        .sum()
}

{
    let fruits=Fruits{
        apples:1,
        oranges:2,
        tangerines:3,
        tomatoes:5,
    };
     
    assert_eq!( total_fruit_count(&fruits), 11 );
}

{
    let fruits=make_struct!{
        apples:8,
        oranges:13,
        tangerines:21,
        tomatoes:34,
    };
     
    assert_eq!( total_fruit_count(&fruits), 76 );
}

#[derive(Structural)]
// We only get read access to the fields.
#[struc(public,access="ref")]
struct Fruits{
    apples:u32,
    oranges:u32,
    tangerines:u32,
    tomatoes:u32,
}

Enum Example

use structural::{StructuralExt,Structural,fp};

with_pc( &Device::Pc{ manufacturer:"dawn", year:2038 } );
with_pc( &MoreDevices::Pc{ manufacturer:"dawn", year:2038 } );

fn with_pc<T>(pc:&T)
where
    // `Device_SI` was generated for Device by the `Structural` derive.
    T: Device_SI
{
    assert_eq!(
        pc.cloned_fields(fp!(::Pc.manufacturer, ::Pc.year)),
        ( Some("dawn"), Some(2038) )
    );

    // You can use `=>` to access multiple fields inside of a nested field(or a variant)
    // this allows accessing multiple fields inside an enum variant without having to
    // create an intermediate variant proxy
    // (look at the next assert for what that looks like).
    assert_eq!( pc.cloned_fields(fp!(::Pc=>manufacturer,year)), Some(("dawn",2038)) );

    assert_eq!(
        // This is equivalent to the field access in the previous assert
        pc.field_(fp!(::Pc)).map(|vp| vp.cloned_fields(fp!(manufacturer,year)) ),
        Some(("dawn",2038))
    );

    assert_eq!( pc.cloned_fields(fp!(::Phone=>number,charge)), None);
}

#[derive(Structural)]
enum Device{
    Pc{manufacturer: &'static str, year:u32},
    Phone{number:&'static str,charge:u8},
}

#[derive(Structural)]
enum MoreDevices{
    Pc{manufacturer: &'static str, year:u32},
    Phone{number:&'static str,charge:u8},
    Tablet,
}

fn field_mut<'a, P>(
    &'a mut self,
    path: P
) -> NormalizeFieldsOut<Result<&'a mut P::Ty, P::Err>> where
    P: RevGetFieldMutImpl<'a, Self>,
    Result<&'a mut P::Ty, P::Err>: NormalizeFields, 

Gets a mutable reference to a field,determined by path.

Example

use structural::{StructuralExt,fp,make_struct,Structural};

#[derive(Structural)]
struct Human{
    pub x:i32,
    pub y:i32,
    pub health:u32,
    flags:u32,
}

// The `Human_SI` trait was declared by the `Structural` derive on `Human`.
fn move_human( this:&mut dyn Human_SI, dx:i32, dy:i32 ){
    *this.field_mut(fp!(x))+=dx;
    *this.field_mut(fp!(y))+=dy;
}

{
    let mut entity=make_struct!{
        x: 0,
        y: 0,
        health: 100,
    };
    move_human(&mut entity,-100,300);
    assert_eq!( entity.fields(fp!(x,y,health)), (&-100,&300,&100) )
}
{
    let mut entity=Human{
        x: -1000,
        y: 1000,
        health: 1,
        flags: 0b11111,
    };
     
    move_human(&mut entity,500,-200);

    assert_eq!( entity.x, -500 );
    assert_eq!( entity.y, 800 );
    assert_eq!( entity.health, 1 );
    assert_eq!( entity.flags, 0b11111 );
}

Enum Example

use structural::{StructuralExt,Structural,fp};

with_soda( &mut Beverage::Soda{ ml:600, cents:400 } );
with_soda( &mut MoreBeverages::Soda{ ml:600, cents:400 } );

fn with_soda<T>(soda:&mut T)
where
    // `Beverage_SI` was generated for Beverage by the `Structural` derive.
    T: Beverage_SI
{
    assert_eq!( soda.field_mut(fp!(::Soda.ml)), Some(&mut 600) );
    assert_eq!( soda.field_mut(fp!(::Soda.cents)), Some(&mut 400) );

    // Constructing the variant proxy is the only Option we have to handle here,
    // instead of every access to the fields in the Soda variant being optional.
    let proxy=soda.field_mut(fp!(::Soda)).expect("Expected a soda");
    assert_eq!( proxy.field_mut(fp!(ml)), &mut 600 );
    assert_eq!( proxy.field_mut(fp!(cents)), &mut 400 );
}

#[derive(Structural)]
enum Beverage{
    Soda{ ml:u32, cents:u32 },
    Water,
}

#[derive(Structural)]
enum MoreBeverages{
    Soda{ ml:u32, cents:u32 },
    Water,
    Beer,
}

fn fields_mut<'a, P>(
    &'a mut self,
    path: P
) -> RevGetMultiFieldMutOut<'a, P, Self> where
    P: RevGetMultiFieldMut<'a, Self>, 

Gets mutable references to multiple fields,determined by path.

Access many fields

If you pass a path that references over 8 fields,this will return a tuple of tuples(each nested tuple with 8 elements) instead of a singly nested tuple.

For examples accessing over 8 field look at the docs for the field_pat macro

Example

use structural::{
    StructuralExt,GetFieldMut,GetFieldType,Structural,
    fp,field_path_aliases,
};

field_path_aliases!{
    mod names{x,y}
}

fn swap_coordinates<T,U>(this:&mut T)
where
    T:GetFieldMut<names::x,Ty=U>,
    T:GetFieldMut<names::y,Ty=U>,
{
    let (x,y)=this.fields_mut(fp!(x,y));
    std::mem::swap(x,y);
}

{
    let mut this=Point2D{ x:100, y:300 };
    swap_coordinates(&mut this);
    assert_eq!( this.x, 300 );
    assert_eq!( this.y, 100 );
}

{
    let mut this=Point3D{ x:30, y:0, z:500 };
    swap_coordinates(&mut this);
    assert_eq!( this.x, 0 );
    assert_eq!( this.y, 30 );
    assert_eq!( this.z, 500 );
}

#[derive(Structural)]
struct Point2D<T>{
    pub x:T,
    pub y:T,
}

#[derive(Structural)]
struct Point3D<T>{
    pub x:T,
    pub y:T,
    pub z:T,
}

Example

An example of how this method does not allow multiple mutable borrows of the same field.

ⓘThis example deliberately fails to compile
use structural::{StructuralExt,fp};

let mut tup=(1,1,2,3,5,8);

let _=tup.fields_mut(fp!(4,4));

Enum Example

use structural::{StructuralExt,Structural,fp};

with_book( &mut Medium::Book{ pages:500, title:"Dracular" } );
with_book( &mut MoreMedia::Book{ pages:500, title:"Dracular" } );

fn with_book<T>(book:&mut T)
where
    // `Medium_SI` was generated for Medium by the `Structural` derive.
    T: Medium_SI
{
    assert_eq!(
        book.fields_mut(fp!(::Book.pages, ::Book.title)),
        ( Some(&mut 500), Some(&mut "Dracular") )
    );

    // You can use `=>` to access multiple fields inside of a nested field(or a variant)
    // this allows accessing multiple fields inside an enum variant without having to
    // create an intermediate variant proxy
    // (look at the next assert for what that looks like).
    assert_eq!(
        book.fields_mut(fp!(::Book=>pages,title)),
        Some((&mut 500,&mut "Dracular")),
    );

    assert_eq!(
        // This is equivalent to the field access in the previous assert
        book.field_mut(fp!(::Book)).map(|vp| vp.fields_mut(fp!(pages,title)) ),
        Some((&mut 500,&mut "Dracular"))
    );

    assert_eq!( book.fields_mut(fp!(::Comic=>artist,in_color)), None);
}

#[derive(Structural)]
enum Medium{
    Book{ pages:u32, title:&'static str },
    Comic{artist:&'static str,in_color:bool},
}

#[derive(Structural)]
enum MoreMedia{
    Book{ pages:u32, title:&'static str },
    Comic{artist:&'static str,in_color:bool},
    Television,
}

fn into_field<P>(self, path: P) -> NormalizeFieldsOut<Result<P::Ty, P::Err>> where
    P: RevIntoFieldImpl<Self>,
    P::Ty: Sized,
    Result<P::Ty, P::Err>: NormalizeFields,
    Self: Sized, 

Converts ´self´ into a field,determined by path.

Example

use structural::{StructuralExt,Structural,fp};


#[derive(Structural,Clone)]
#[struc(public,access="move")]
struct Tupled<T>(T,T,T,T);

// The `Tupled_SI` trait was declared by the `Structural` derive on `Tupled`.
fn pick_index<T>(this:impl Tupled_SI<T>,which_one:u32)->T{
    match which_one % 4 {
        0=>this.into_field(fp!(0)),
        1=>this.into_field(fp!(1)),
        2=>this.into_field(fp!(2)),
        _=>this.into_field(fp!(3)),
    }
}

{
    let tup=Tupled(13,21,34,55);
     
    assert_eq!( pick_index(tup.clone(),0), 13 );
    assert_eq!( pick_index(tup.clone(),1), 21 );
    assert_eq!( pick_index(tup.clone(),2), 34 );
    assert_eq!( pick_index(tup        ,3), 55 );
}

{
    let array=[13,21,34,55];
     
    assert_eq!( pick_index(array.clone(),0), 13 );
    assert_eq!( pick_index(array.clone(),1), 21 );
    assert_eq!( pick_index(array.clone(),2), 34 );
    assert_eq!( pick_index(array        ,3), 55 );
}

Enum Example

use structural::{StructuralExt,Structural,fp};

with_table( &Furniture::Table{ height_cm:101, width_cm:333 } );
with_table( &MoreFurniture::Table{ height_cm:101, width_cm:333 } );

fn with_table<T>(table:&T)
where
    // `Furniture_SI` was generated for Furniture by the `Structural` derive.
    T: Furniture_SI + Clone
{
    assert_eq!( table.clone().into_field(fp!(::Table.height_cm)), Some(101) );
    assert_eq!( table.clone().into_field(fp!(::Table.width_cm)), Some(333) );

    // Constructing the variant proxy is the only Option we have to handle here,
    // instead of every access to the fields in the Table variant being optional.
    let proxy=table.clone().into_field(fp!(::Table)).expect("Expected a table");
    assert_eq!( proxy.clone().into_field(fp!(height_cm)), 101 );
    assert_eq!( proxy.clone().into_field(fp!(width_cm)), 333 );
}

#[derive(Structural,Clone)]
enum Furniture{
    Table{ height_cm:u32, width_cm:u32 },
    Chair,
}

#[derive(Structural,Clone)]
enum MoreFurniture{
    Table{ height_cm:u32, width_cm:u32 },
    Chair,
    Sofa,
}

fn into_fields<P>(self, path: P) -> RevIntoMultiFieldOut<P, Self> where
    P: RevIntoMultiField<Self>,
    Self: Sized, 

Converts self into multiple fields by value.

Access many fields

If you pass a path that references over 8 fields,this will return a tuple of tuples(each nested tuple with 8 elements) instead of a singly nested tuple.

For examples accessing over 8 field look at the docs for the field_pat macro

Valid Paths

As opposed to the other multiple fields accessor methods, this method only accepts field paths that refer to multiple non-nested fields inside some value (possibly a nested field itself).

Examples of accepted field paths:

  • fp!(a, b, c): Accesses the a,b,and c fields.

  • fp!(a.b.c=> d, e, f): Accesses the d,e,and f fields inside the a.b.c field.

  • fp!(::Foo=> bar, baz): Accesses the bar and baz field in the Foo variant.

Examples of rejected field paths(accepted in other methods):

  • fp!(a.b, c)

  • fp!(a.b, c.d)

  • fp!(::Bar=> a.b, c.d)

Struct Example

use structural::{StructuralExt,fp,make_struct};
use structural::for_examples::{Struct2, Struct2_SI, Struct3};

assert_eq!(
    into_struct2(Struct3{ foo:Some("13".to_string()), bar: 21, baz: 34}),
    Struct2{ foo:Some("13".to_string()), bar: 21 }
);

{
    let value=Struct2{ foo:Some(vec![55, 89]), bar: 144 };
    assert_eq!( into_struct2(value.clone()), value );
}

assert_eq!(
    into_struct2(make_struct!{
        foo: None::<()>,
        bar: 233,
        baz: false,
        qux: "hello".to_string()
    }),
    Struct2{ foo:None, bar: 233 }
);

// `Struct2_SI` was declared by the `Structural` derive on `Struct2`,
// aliasing the accessor traits that `Struct2` implements.
fn into_struct2<T,U>(this: impl Struct2_SI<T,U>)->Struct2<T,U>{
    let (foo, bar)=this.into_fields(fp!(foo, bar));
    Struct2{foo, bar}
}

Enum Example

use structural::{StructuralExt,fp};
use structural::for_examples::{Enum1, Enum1_SI, Enum2, Enum3};

use std::cmp::Ordering;

assert_eq!( into_enum1(Enum1::Foo(3, 5)), Some(Enum1::Foo(3, 5)) );

assert_eq!( into_enum1(Enum2::Foo(8, 13)), Some(Enum1::Foo(8, 13)) );
assert_eq!( into_enum1(Enum2::Bar(Ordering::Less, None)), None );

assert_eq!( into_enum1(Enum3::Foo(21, 34)), Some(Enum1::Foo(21, 34)) );
assert_eq!( into_enum1(Enum3::Bar(Ordering::Less, None)), None );
assert_eq!( into_enum1(Enum3::Baz { foom: "whoop"}), None );

// `Enum1_SI` was declared by the `Structural` derive on `Enum1`,
// aliasing the accessor traits that `Enum1` implements.
fn into_enum1(this: impl Enum1_SI)-> Option<Enum1> {
    this.into_fields(fp!(::Foo=>0,1))
        .map(|(a,b)| Enum1::Foo(a,b) )
}

fn is_variant<P>(&self, _path: P) -> bool where
    P: IsTStr,
    Self: IsVariant<P>, 

Checks whether an enum is a particular variant.

Example

use structural::{StructuralExt,Structural,fp};

check_colors( &Color::Red, &Color::Blue, &Color::Green );
check_colors( &ColorPlus::Red, &ColorPlus::Blue, &ColorPlus::Green );

fn check_colors<T>( red:&T, blue:&T, green:&T )
where
    // `Color_SI` was declared by the `Structural` derive on `Color`,
    // aliasing the accessor traits that `Color` implements.
    T: Color_SI
{
    assert!(  red.is_variant(fp!(Red)) );
    assert!( !red.is_variant(fp!(Blue)) );
    assert!( !red.is_variant(fp!(Green)) );

    assert!( !blue.is_variant(fp!(Red)) );
    assert!(  blue.is_variant(fp!(Blue)) );
    assert!( !blue.is_variant(fp!(Green)) );

    assert!( !green.is_variant(fp!(Red)) );
    assert!( !green.is_variant(fp!(Blue)) );
    assert!(  green.is_variant(fp!(Green)) );
}

#[derive(Structural)]
enum Color{
    Red,
    Blue,
    Green,
}

#[derive(Structural)]
enum ColorPlus{
    Red,
    Blue,
    Green,
    Teal,
    White,
    Gray,
    Black,
}

fn into_struc<U>(self) -> U where
    Self: IntoStructural<U>, 

Converts this into another structural type using IntoStructural.

Struct Example

use structural::{
    Structural, StructuralExt, fp, make_struct,
};

assert_eq!( Foo(55, 89, 144, 233).into_struc::<[_;3]>(), [55, 89, 144] );

assert_eq!(
    make_struct!{x:"foo", y:"bar", z:"baz", w:"what"}.into_struc::<Point<_>>(),
    Point{x:"foo", y:"bar", z:"baz"}
);

#[derive(Debug,Structural,PartialEq)]
struct Foo(pub u8, pub u8, pub u8, pub u8);

#[derive(Debug,Structural,PartialEq)]
struct Point<T>{
    pub x: T,
    pub y: T,
    pub z: T,
}

// This macro also implement TryFromStructural for Point
structural::z_impl_from_structural!{
    impl[F, T] FromStructural<F> for Point<T>
    where[
        // `Point_SI` was generated for `Point` by the Structural derive.
        F: Point_SI<T>,
    ]{
        fn from_structural(this){
            let (x,y,z) = this.into_fields(fp!(x, y, z));
            Self{x,y,z}
        }
    }
}

Enum example

use structural::{
    for_examples::ResultLike,
    Structural, StructuralExt, switch,
};

assert_eq!( ResultLike::<_,()>::Ok (300).into_struc::<ResultV>(), ResultV::Ok );
assert_eq!( ResultLike::<(),_>::Err(300).into_struc::<ResultV>(), ResultV::Err );

assert_eq!( Ok::<_,()>(300).into_struc::<ResultV>(), ResultV::Ok );
assert_eq!( Err::<(),_>(300).into_struc::<ResultV>(), ResultV::Err );

#[derive(Debug,Structural,PartialEq)]
enum ResultV{
    Ok,
    Err,
}

// This macro also implement TryFromStructural for ResultV
structural::z_impl_from_structural!{
    impl[F] FromStructural<F> for ResultV
    where[
        // `ResultV_ESI` was generated for `Point` by the Structural derive.
        F: ResultV_ESI
    ]{
        fn from_structural(this){
            switch!{this;
                Ok => ResultV::Ok,
                Err => ResultV::Err,
            }
        }
    }
}

fn try_into_struc<U>(self) -> Result<U, TryFromError<Self, Self::Error>> where
    Self: TryIntoStructural<U>, 

Performs a fallible conversion into another structural type using TryIntoStructural.

Enum example

use structural::{
    convert::{EmptyTryFromError, TryFromError},
    for_examples::ResultLike,
    Structural, StructuralExt, switch,
};

assert_eq!( Shapes::Rectangle.try_into_struc::<Shapes>(), Ok(Shapes::Rectangle) );
assert_eq!( Shapes::Circle.try_into_struc::<Shapes>()   , Ok(Shapes::Circle) );

assert_eq!( MoreShapes::Rectangle.try_into_struc::<Shapes>(), Ok(Shapes::Rectangle) );
assert_eq!( MoreShapes::Circle.try_into_struc::<Shapes>()   , Ok(Shapes::Circle) );
assert_eq!(
    MoreShapes::Hexagon.try_into_struc::<Shapes>(),
    Err(TryFromError::with_empty_error(MoreShapes::Hexagon)),
);

#[derive(Debug,Structural,PartialEq)]
enum Shapes{
    Rectangle,
    Circle,
}

#[derive(Debug,Structural,PartialEq)]
enum MoreShapes{
    Rectangle,
    Circle,
    Hexagon,
}

// This macro implements FromStructural in terms of TryFromStructural,
structural::z_impl_try_from_structural_for_enum!{
    impl[F] TryFromStructural<F> for Shapes
    where[ F: Shapes_SI, ]
    {
        type Error = EmptyTryFromError;

        fn try_from_structural(this){
            switch! {this;
                Rectangle => Ok(Self::Rectangle),
                Circle => Ok(Self::Circle),
                _ => Err(TryFromError::with_empty_error(this)),
            }
        }
    }

    // `Shapes_ESI` was generated by the `Structural` derive for `Shapes`
    // aliasing its accessor trait impls,
    // and requires `F` to only have the `Rectangle` and `Circle` variants.
    FromStructural
    where[ F: Shapes_ESI, ]
}
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Implementors

impl<T: ?Sized> StructuralExt for T[src]

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