#derive #macro #trait #field #procedural

macro no-std educe

This crate provides procedural macros to help you implement Rust-built-in traits quickly

13 releases (4 breaking)

✓ Uses Rust 2018 edition

new 0.4.2 Sep 19, 2019
0.4.1 Sep 16, 2019
0.4.0 Aug 4, 2019
0.3.0 Aug 4, 2019
0.0.7 Jul 31, 2019

#39 in Rust patterns

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Used in 15 crates (8 directly)

MIT license

570KB
10K SLoC

Educe

Build Status

This crate provides procedural macros to help you implement Rust-built-in traits quickly.

Features

By default, every trait this crate supports will be enabled. You can disable all of them by disabling the default features and enable only the traits that you want to use by adding them to features explictly.

For example,

[dependencies.educe]
version = "*"
features = ["Debug", "Default", "Hash", "Clone", "Copy"]
default-features = false

Debug

Use #[derive(Educe)] and #[educe(Debug)] to implement the Debug trait for a struct, an enum, or a union. It supports to change the name of your types, variants and fields. You can also ignore some fields, or set a trait and/or a method to replace the Debug trait used by default. Also, you can even format a struct to a tuple, and vice versa.

Basic Usage

#[macro_use] extern crate educe;

#[derive(Educe)]
#[educe(Debug)]
struct Struct {
    f1: u8
}

#[derive(Educe)]
#[educe(Debug)]
enum Enum {
    V1,
    V2 {
        f1: u8,
    },
    V3(u8),
}

Change the Name of a Type, a Variant or a Field

The name attribute can help you rename a type, a variant or a field.

#[macro_use] extern crate educe;

#[derive(Educe)]
#[educe(Debug(name = "Struct2"))]
struct Struct {
    #[educe(Debug(name = "f"))]
    f1: u8
}

#[derive(Educe)]
#[educe(Debug(name = true))]
enum Enum {
    #[educe(Debug(name = false))]
    V1,
    #[educe(Debug(name = "V"))]
    V2 {
        #[educe(Debug(name = "f"))]
        f1: u8,
    },
    #[educe(Debug(name = false))]
    V3(u8),
}

Ignore Fields

The ignore attribute can ignore specific fields.

#[macro_use] extern crate educe;

#[derive(Educe)]
#[educe(Debug)]
struct Struct {
    #[educe(Debug(ignore))]
    f1: u8
}

#[derive(Educe)]
#[educe(Debug)]
enum Enum {
    V1,
    V2 {
        #[educe(Debug(ignore))]
        f1: u8,
    },
    V3(
        #[educe(Debug(ignore))]
        u8
    ),
}

Fake Structs and Tuples

With the named_field attribute, structs can be formatted as tuples and tuples can be formatted as structs.

#[macro_use] extern crate educe;

#[derive(Educe)]
#[educe(Debug(named_field = false))]
struct Struct {
    f1: u8
}

#[derive(Educe)]
#[educe(Debug)]
enum Enum {
    V1,
    #[educe(Debug(named_field = false))]
    V2 {
        f1: u8,
    },
    #[educe(Debug(named_field = true))]
    V3(
        u8,
        #[educe(Debug(name = "value"))]
        i32
    ),
}

Use Another Method or Trait to Do the Format Thing

The trait and method attributes can be used to replace the Debug trait for fields. If you only set the trait parameter, the method will be set to fmt automatically by default.

#[macro_use] extern crate educe;

use std::fmt::{self, Formatter};

fn fmt(_s: &u8, f: &mut Formatter) -> fmt::Result {
    f.write_str("Hi")
}

trait A {
    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
        f.write_str("Hi")
    }
}

impl A for i32 {};
impl A for u64 {};

#[derive(Educe)]
#[educe(Debug)]
enum Enum<T: A> {
    V1,
    V2 {
        #[educe(Debug(method = "fmt"))]
        f1: u8,
    },
    V3(
        #[educe(Debug(trait = "std::fmt::UpperHex"))]
        u8,
        #[educe(Debug(trait = "A"))]
        T
    ),
}

Generic Parameters Bound to the Debug Trait or Others

The #[educe(Debug(bound))] attribute can be used to add the Debug trait bound to all generaic parameters for the Debug implementation.

#[macro_use] extern crate educe;

#[derive(Educe)]
#[educe(Debug(bound))]
enum Enum<T, K> {
    V1,
    V2 {
        f1: K,
    },
    V3(
        T
    ),
}

Or you can set the where predicates by yourself.

#[macro_use] extern crate educe;

use std::fmt::{self, Formatter};

fn fmt(_s: &u8, f: &mut Formatter) -> fmt::Result {
    f.write_str("Hi")
}

trait A {
    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
        f.write_str("Hi")
    }
}

impl A for i32 {};
impl A for u64 {};

#[derive(Educe)]
#[educe(Debug(bound = "T: std::fmt::Debug, K: A"))]
enum Enum<T, K> {
    V1,
    V2 {
        #[educe(Debug(trait = "A"))]
        f1: K,
    },
    V3(
        T
    ),
}

Union

A union will be formatted to a u8 slice, because we don't know it's field at runtime. The fields of a union cannot be ignored, renamed or formated with other methods or traits.

#[macro_use] extern crate educe;

#[derive(Educe)]
#[educe(Debug)]
struct Union {
    f1: u8,
    f2: i32,
}

PartialEq

Use #[derive(Educe)] and #[educe(ParitalEq)] to implement the ParitalEq trait for a struct or an enum. It supports to ignore some fields, or set a trait and/or a method to replace the ParitalEq trait used by default.

Basic Usage

#[macro_use] extern crate educe;

#[derive(Educe)]
#[educe(PartialEq)]
struct Struct {
    f1: u8
}

#[derive(Educe)]
#[educe(PartialEq)]
enum Enum {
    V1,
    V2 {
        f1: u8,
    },
    V3(u8),
}

Ignore Fields

The ignore attribute can ignore specific fields.

#[macro_use] extern crate educe;

#[derive(Educe)]
#[educe(PartialEq)]
struct Struct {
    #[educe(PartialEq(ignore))]
    f1: u8
}

#[derive(Educe)]
#[educe(PartialEq)]
enum Enum {
    V1,
    V2 {
        #[educe(PartialEq(ignore))]
        f1: u8,
    },
    V3(
        #[educe(PartialEq(ignore))]
        u8
    ),
}

Use Another Method or Trait to Do Comparing

The trait and method attributes can be used to replace the PartialEq trait for fields. If you only set the trait parameter, the method will be set to eq automatically by default.

#[macro_use] extern crate educe;

fn eq(a: &u8, b: &u8) -> bool {
    a + 1 == *b
}

trait A {
    fn eq(&self, b: &Self) -> bool;
}

impl A for i32 {
    fn eq(&self, b: &i32) -> bool {
        self + 1 == *b
    }
}

impl A for u64 {
    fn eq(&self, b: &u64) -> bool {
        self + 1 == *b
    }
}

#[derive(Educe)]
#[educe(PartialEq)]
enum Enum<T: A> {
    V1,
    V2 {
        #[educe(PartialEq(method = "eq"))]
        f1: u8,
    },
    V3(
        #[educe(PartialEq(trait = "A"))]
        T
    ),
}

Generic Parameters Bound to the PartialEq Trait or Others

The #[educe(PartialEq(bound))] attribute can be used to add the PartialEq trait bound to all generaic parameters for the PartialEq implementation.

#[macro_use] extern crate educe;

#[derive(Educe)]
#[educe(PartialEq(bound))]
enum Enum<T, K> {
    V1,
    V2 {
        f1: K,
    },
    V3(
        T
    ),
}

Or you can set the where predicates by yourself.

#[macro_use] extern crate educe;

trait A {
    fn eq(&self, b: &Self) -> bool;
}

impl A for i32 {
    fn eq(&self, b: &i32) -> bool {
        self + 1 == *b
    }
}

impl A for u64 {
    fn eq(&self, b: &u64) -> bool {
        self + 1 == *b
    }
}

#[derive(Educe)]
#[educe(PartialEq(bound = "T: std::cmp::PartialEq, K: A"))]
enum Enum<T, K> {
    V1,
    V2 {
        #[educe(PartialEq(trait = "A"))]
        f1: K,
    },
    V3(
        T
    ),
}

Eq

Use #[derive(Educe)] and #[educe(Eq)] to implement the Eq trait for a struct, an enum or a union.

Basic Usage

#[macro_use] extern crate educe;

#[derive(Educe)]
#[educe(PartialEq, Eq)]
struct Struct {
    f1: u8
}

#[derive(Educe)]
#[educe(PartialEq, Eq)]
enum Enum {
    V1,
    V2 {
        f1: u8,
    },
    V3(u8),
}

Generic Parameters Bound to the Eq Trait or Others

The #[educe(Eq(bound))] attribute can be used to add the Eq trait bound to all generaic parameters for the Eq implementation.

#[macro_use] extern crate educe;

#[derive(Educe)]
#[educe(PartialEq(bound), Eq(bound))]
enum Enum<T, K> {
    V1,
    V2 {
        f1: K,
    },
    V3(
        T
    ),
}

Or you can set the where predicates by yourself. (NOTE: The Eq trait depends on the PartialEq (PartialEq<Self>) trait.)

#[macro_use] extern crate educe;

trait A {
    fn eq(&self, b: &Self) -> bool;
}

impl A for i32 {
    fn eq(&self, b: &i32) -> bool {
        self + 1 == *b
    }
}

impl A for u64 {
    fn eq(&self, b: &u64) -> bool {
        self + 1 == *b
    }
}

#[derive(Educe)]
#[educe(PartialEq(bound = "T: std::cmp::PartialEq, K: A"), Eq(bound = "T: std::cmp::PartialEq, K: A"))]
enum Enum<T, K> {
    V1,
    V2 {
        #[educe(PartialEq(trait = "A"))]
        f1: K,
    },
    V3(
        T
    ),
}

PartialOrd

Use #[derive(Educe)] and #[educe(PartialOrd)] to implement the PartialOrd trait for a struct or an enum. It supports to ignore some fields, or set a trait and/or a method to replace the PartialOrd trait used by default. The rank of variants and fields can also be modified.

Basic Usage

#[macro_use] extern crate educe;

#[derive(Educe)]
#[educe(PartialEq, PartialOrd)]
struct Struct {
    f1: u8
}

#[derive(Educe)]
#[educe(PartialEq, PartialOrd)]
enum Enum {
    V1,
    V2 {
        f1: u8,
    },
    V3(u8),
}

Ignore Fields

The ignore attribute can ignore specific fields.

#[macro_use] extern crate educe;

#[derive(Educe)]
#[educe(PartialEq, PartialOrd)]
struct Struct {
    #[educe(PartialOrd(ignore))]
    f1: u8
}

#[derive(Educe)]
#[educe(PartialEq, PartialOrd)]
enum Enum {
    V1,
    V2 {
        #[educe(PartialOrd(ignore))]
        f1: u8,
    },
    V3(
        #[educe(PartialOrd(ignore))]
        u8
    ),
}

Use Another Method or Trait to Do Comparing

The trait and method attributes can be used to replace the PartialOrd trait for fields. If you only set the trait parameter, the method will be set to partial_cmp automatically by default.

#[macro_use] extern crate educe;

use std::cmp::Ordering;

fn partial_cmp(a: &u8, b: &u8) -> Option<Ordering> {
    if a > b {
        Some(Ordering::Less)
    } else if a < b {
        Some(Ordering::Greater)
    } else {
        Some(Ordering::Equal)
    }
}

trait A {
    fn partial_cmp(&self, b: &Self) -> Option<Ordering>;
}

impl A for i32 {
    fn partial_cmp(&self, b: &i32) -> Option<Ordering> {
        if self > b {
            Some(Ordering::Less)
        } else if self < b {
            Some(Ordering::Greater)
        } else {
            Some(Ordering::Equal)
        }
    }
}

#[derive(Educe)]
#[educe(PartialEq, PartialOrd)]
enum Enum<T: std::cmp::PartialEq + A> {
    V1,
    V2 {
        #[educe(PartialOrd(method = "partial_cmp"))]
        f1: u8,
    },
    V3(
        #[educe(PartialOrd(trait = "A"))]
        T
    ),
}

Generic Parameters Bound to the PartialOrd Trait or Others

The #[educe(PartialOrd(bound))] attribute can be used to add the PartialOrd trait bound to all generaic parameters for the PartialOrd implementation.

#[macro_use] extern crate educe;

#[derive(Educe)]
#[educe(PartialEq(bound), PartialOrd(bound))]
enum Enum<T, K> {
    V1,
    V2 {
        f1: K,
    },
    V3(
        T
    ),
}

Or you can set the where predicates by yourself. (NOTE: The PartialOrd trait depends on the PartialEq (PartialEq<Self>) trait.)

#[macro_use] extern crate educe;

use std::cmp::Ordering;

trait A {
    fn partial_cmp(&self, b: &Self) -> Option<Ordering>;
}

impl A for i32 {
    fn partial_cmp(&self, b: &i32) -> Option<Ordering> {
        if self > b {
            Some(Ordering::Less)
        } else if self < b {
            Some(Ordering::Greater)
        } else {
            Some(Ordering::Equal)
        }
    }
}

#[derive(Educe)]
#[educe(PartialEq(bound), PartialOrd(bound = "T: std::cmp::PartialOrd, K: std::cmp::PartialOrd + A"))]
enum Enum<T, K> {
    V1,
    V2 {
        #[educe(PartialOrd(trait = "A"))]
        f1: K,
    },
    V3(
        T
    ),
}

Ranking

Each field can add a #[educe(PartialOrd(rank = priority_value))] attribute where priority_value is a positive integer value to determine their comparing precedence (lower priority_value leads to higher priority). The default priority_value for a field dependends on its ordinal (the lower the front) and is always lower than any custom priority_value.

#[macro_use] extern crate educe;

#[derive(Educe)]
#[educe(PartialEq, PartialOrd)]
struct Struct {
    #[educe(PartialOrd(rank = 1))]
    f1: u8,
    #[educe(PartialOrd(rank = 0))]
    f2: u8,
}

Each variant can add a #[educe(PartialOrd(rank = comparison_value))] attribute where comparison_value is a positive integer value to override the value or the ordinal of a variant for comparison.

#[macro_use] extern crate educe;

#[derive(Educe)]
#[educe(PartialEq, PartialOrd)]
enum Enum {
    #[educe(PartialOrd(rank = 2))]
    Two,
    #[educe(PartialOrd(rank = 1))]
    One,
}

Ord

Use #[derive(Educe)] and #[educe(Ord)] to implement the Ord trait for a struct or an enum. It supports to ignore some fields, or set a trait and/or a method to replace the Ord trait used by default. The rank of variants and fields can also be modified.

Basic Usage

#[macro_use] extern crate educe;

#[derive(Educe)]
#[educe(PartialEq, Eq, PartialOrd, Ord)]
struct Struct {
    f1: u8
}

#[derive(Educe)]
#[educe(PartialEq, Eq, PartialOrd, Ord)]
enum Enum {
    V1,
    V2 {
        f1: u8,
    },
    V3(u8),
}

Ignore Fields

The ignore attribute can ignore specific fields.

#[macro_use] extern crate educe;

#[derive(Educe)]
#[educe(PartialEq, Eq, PartialOrd, Ord)]
struct Struct {
    #[educe(Ord(ignore))]
    f1: u8
}

#[derive(Educe)]
#[educe(PartialEq, Eq, PartialOrd, Ord)]
enum Enum {
    V1,
    V2 {
        #[educe(Ord(ignore))]
        f1: u8,
    },
    V3(
        #[educe(Ord(ignore))]
        u8
    ),
}

Use Another Method or Trait to Do Comparing

The trait and method attributes can be used to replace the Ord trait for fields. If you only set the trait parameter, the method will be set to cmp automatically by default.

#[macro_use] extern crate educe;

use std::cmp::Ordering;

fn cmp(a: &u8, b: &u8) -> Ordering {
    if a > b {
        Ordering::Less
    } else if a < b {
        Ordering::Greater
    } else {
        Ordering::Equal
    }
}

trait A {
    fn cmp(&self, b: &Self) -> Ordering;
}

impl A for i32 {
    fn cmp(&self, b: &i32) -> Ordering {
        if self > b {
            Ordering::Less
        } else if self < b {
            Ordering::Greater
        } else {
            Ordering::Equal
        }
    }
}

#[derive(Educe)]
#[educe(PartialEq, Eq, PartialOrd, Ord)]
enum Enum<T: std::cmp::PartialOrd + A> {
    V1,
    V2 {
        #[educe(Ord(method = "cmp"))]
        f1: u8,
    },
    V3(
        #[educe(Ord(trait = "A"))]
        T
    ),
}

Generic Parameters Bound to the Ord Trait or Others

The #[educe(Ord(bound))] attribute can be used to add the Ord trait bound to all generaic parameters for the Ord implementation.

#[macro_use] extern crate educe;

#[derive(Educe)]
#[educe(PartialEq(bound), Eq(bound), PartialOrd(bound), Ord(bound))]
enum Enum<T, K> {
    V1,
    V2 {
        f1: K,
    },
    V3(
        T
    ),
}

Or you can set the where predicates by yourself. (NOTE: The Ord trait depends on the PartialOrd (PartialOrd<Self>) trait and the Eq trait.)

#[macro_use] extern crate educe;

use std::cmp::Ordering;

trait A {
    fn cmp(&self, b: &Self) -> Ordering;
}

impl A for i32 {
    fn cmp(&self, b: &i32) -> Ordering {
        if self > b {
            Ordering::Less
        } else if self < b {
            Ordering::Greater
        } else {
            Ordering::Equal
        }
    }
}

#[derive(Educe)]
#[educe(PartialEq(bound), Eq(bound), PartialOrd(bound), Ord(bound = "T: std::cmp::Ord, K: std::cmp::Ord + A"))]
enum Enum<T, K> {
    V1,
    V2 {
        #[educe(Ord(trait = "A"))]
        f1: K,
    },
    V3(
        T
    ),
}

Ranking

Each field can add a #[educe(Ord(rank = priority_value))] attribute where priority_value is a positive integer value to determine their comparing precedence (lower priority_value leads to higher priority). The default priority_value for a field dependends on its ordinal (the lower the front) and is always lower than any custom priority_value.

#[macro_use] extern crate educe;

#[derive(Educe)]
#[educe(PartialEq, Eq, PartialOrd, Ord)]
struct Struct {
    #[educe(Ord(rank = 1))]
    f1: u8,
    #[educe(Ord(rank = 0))]
    f2: u8,
}

Each variant can add a #[educe(Ord(rank = comparison_value))] attribute where comparison_value is a positive integer value to override the value or the ordinal of a variant for comparison.

#[macro_use] extern crate educe;

#[derive(Educe)]
#[educe(PartialEq, Eq, PartialOrd, Ord)]
enum Enum {
    #[educe(Ord(rank = 2))]
    Two,
    #[educe(Ord(rank = 1))]
    One,
}

Hash

Use #[derive(Educe)] and #[educe(Hash)] to implement the Hash trait for a struct or an enum. It supports to ignore some fields, or set a trait and/or a method to replace the Hash trait used by default.

Basic Usage

#[macro_use] extern crate educe;

#[derive(Educe)]
#[educe(Hash)]
struct Struct {
    f1: u8
}

#[derive(Educe)]
#[educe(Hash)]
enum Enum {
    V1,
    V2 {
        f1: u8,
    },
    V3(u8),
}

Ignore Fields

The ignore attribute can ignore specific fields.

#[macro_use] extern crate educe;

#[derive(Educe)]
#[educe(Hash)]
struct Struct {
    #[educe(Hash(ignore))]
    f1: u8
}

#[derive(Educe)]
#[educe(Hash)]
enum Enum {
    V1,
    V2 {
        #[educe(Hash(ignore))]
        f1: u8,
    },
    V3(
        #[educe(Hash(ignore))]
        u8
    ),
}

Use Another Method or Trait to Do Hashing

The trait and method attributes can be used to replace the Hash trait for fields. If you only set the trait parameter, the method will be set to hash automatically by default.

#[macro_use] extern crate educe;

use std::hash::{Hash, Hasher};

fn hash<H: Hasher>(_s: &u8, state: &mut H) {
    Hash::hash(&100, state)
}

trait A {
    fn hash<H: Hasher>(&self, state: &mut H) {
        Hash::hash(&100, state)
    }
}

impl A for i32 {};
impl A for u64 {};

#[derive(Educe)]
#[educe(Hash)]
enum Enum<T: A> {
    V1,
    V2 {
        #[educe(Hash(method = "hash"))]
        f1: u8,
    },
    V3(
        #[educe(Hash(trait = "A"))]
        T
    ),
}

Generic Parameters Bound to the Hash Trait or Others

The #[educe(Hash(bound))] attribute can be used to add the Hash trait bound to all generaic parameters for the Hash implementation.

#[macro_use] extern crate educe;

#[derive(Educe)]
#[educe(Hash(bound))]
enum Enum<T, K> {
    V1,
    V2 {
        f1: K,
    },
    V3(
        T
    ),
}

Or you can set the where predicates by yourself.

#[macro_use] extern crate educe;

use std::hash::{Hash, Hasher};

fn hash<H: Hasher>(_s: &u8, state: &mut H) {
    Hash::hash(&100, state)
}

trait A {
    fn hash<H: Hasher>(&self, state: &mut H) {
        Hash::hash(&100, state)
    }
}

impl A for i32 {};
impl A for u64 {};

#[derive(Educe)]
#[educe(Hash(bound = "T: std::hash::Hash, K: A"))]
enum Enum<T, K> {
    V1,
    V2 {
        #[educe(Hash(trait = "A"))]
        f1: K,
    },
    V3(
        T
    ),
}

Default

Use #[derive(Educe)] and #[educe(Default)] to implement the Default trait for a struct, an enum, or a union. It supports to set the default value for your type directly, or set the default values for specific fields.

Basic Usage

For enums and unions, you need to assign a variant (of a enum) and a field (of a union) as default unless the number of variants of an enum or the number of fields of a union is exactly one.

#[macro_use] extern crate educe;

#[derive(Educe)]
#[educe(Default)]
struct Struct {
    f1: u8
}

#[derive(Educe)]
#[educe(Default)]
enum Enum {
    V1,
    #[educe(Default)]
    V2 {
        f1: u8,
    },
    V3(u8),
}

#[derive(Educe)]
#[educe(Default)]
union Union {
    f1: u8,
    #[educe(Default)]
    f2: f64,
}

The Default Value for the Whole Type

The #[educe(Default(expression = "expression"))] attribute can be used to set the default value for your type by an expression.

#[macro_use] extern crate educe;

#[derive(Educe)]
#[educe(Default(expression = "Struct { f1: 1 }"))]
struct Struct {
    f1: u8
}

#[derive(Educe)]
#[educe(Default(expression = "Enum::Struct { f1: 1 }"))]
enum Enum {
    Unit,
    Struct {
        f1: u8
    },
    Tuple(u8),
}

#[derive(Educe)]
#[educe(Default(expression = "Union { f1: 1 }"))]
union Union {
    f1: u8,
    f2: f64,
}

The Default Values for Specific Fields

The #[educe(Default = literal)] attribute or the #[educe(Default(expression = "expression"))] attribute can be used to set the default value for a specific field by a literal value or an expression.

#[macro_use] extern crate educe;

#[derive(Educe)]
#[educe(Default)]
struct Struct {
    #[educe(Default = 1)]
    f1: u8,
    #[educe(Default = 11111111111111111111111111111)]
    f2: i128,
    #[educe(Default = 1.1)]
    f3: f64,
    #[educe(Default = true)]
    f4: bool,
    #[educe(Default = "Hi")]
    f5: &'static str,
    #[educe(Default = "Hello")]
    f6: String,
    #[educe(Default = 'M')]
    f7: char,
}

#[derive(Educe)]
#[educe(Default)]
enum Enum {
    Unit,
    #[educe(Default)]
    Tuple(
        #[educe(Default(expression = "0 + 1"))]
        u8,
        #[educe(Default(expression = "-11111111111111111111111111111 * -1"))]
        i128,
        #[educe(Default(expression = "1.0 + 0.1"))]
        f64,
        #[educe(Default(expression = "!false"))]
        bool,
        #[educe(Default(expression = "\"Hi\""))]
        &'static str,
        #[educe(Default(expression = "String::from(\"Hello\")"))]
        String,
        #[educe(Default(expression = "'M'"))]
        char,
    ),
}

#[derive(Educe)]
#[educe(Default)]
union Union {
    f1: u8,
    f2: i128,
    f3: f64,
    f4: bool,
    #[educe(Default = "Hi")]
    f5: &'static str,
    f6: char,
}

Generic Parameters Bound to the Default Trait or Others

The #[educe(Default(bound))] attribute can be used to add the Default trait bound to all generaic parameters for the Default implementation.

#[macro_use] extern crate educe;

#[derive(Educe)]
#[educe(Default(bound))]
enum Enum<T> {
    Unit,
    #[educe(Default)]
    Struct {
        f1: T
    },
    Tuple(T),
}

Or you can set the where predicates by yourself.

#[macro_use] extern crate educe;

#[derive(Educe)]
#[educe(Default(bound = "T: std::default::Default"))]
enum Enum<T> {
    Unit,
    #[educe(Default)]
    Struct {
        f1: T
    },
    Tuple(T),
}

The new Associated Function

With the #[educe(Default(new))] attribute, your type will have an extra associated function called new. That can be used to invoke the default method of the Default trait.

#[macro_use] extern crate educe;

#[derive(Educe)]
#[educe(Default(new))]
struct Struct {
    f1: u8
}

Clone

Use #[derive(Educe)] and #[educe(Clone)] to implement the Clone trait for a struct, an enum, or a union. It supports to set a trait and/or a method to replace the Clone trait used by default.

Basic Usage

#[macro_use] extern crate educe;

#[derive(Educe)]
#[educe(Clone)]
struct Struct {
    f1: u8
}

#[derive(Educe)]
#[educe(Clone)]
enum Enum {
    V1,
    V2 {
        f1: u8,
    },
    V3(u8),
}

Use Another Method or Trait to Do Cloning

The trait and method attributes can be used to replace the Clone trait for fields. If you only set the trait parameter, the method will be set to clone automatically by default.

#[macro_use] extern crate educe;

fn clone(v: &u8) -> u8 {
    v + 100
}

trait A {
    fn clone(&self) -> Self;
}

impl A for i32 {
    fn clone(&self) -> i32 {
        self + 100
    }
}

impl A for u64 {
    fn clone(&self) -> u64 {
        self + 100
    }
}

#[derive(Educe)]
#[educe(Clone)]
enum Enum<T: A> {
    V1,
    V2 {
        #[educe(Clone(method = "clone"))]
        f1: u8,
    },
    V3(
        #[educe(Clone(trait = "A"))]
        T
    ),
}

Generic Parameters Bound to the Clone Trait or Others

The #[educe(Clone(bound))] attribute can be used to add the Clone trait bound or the Copy trait bound (if the #[educe(Copy)] attribute exists) to all generaic parameters for the Clone implementation.

#[macro_use] extern crate educe;

#[derive(Educe)]
#[educe(Clone(bound))]
enum Enum<T, K> {
    V1,
    V2 {
        f1: K,
    },
    V3(
        T
    ),
}

Or you can set the where predicates by yourself.

#[macro_use] extern crate educe;

fn clone(v: &u8) -> u8 {
    v + 100
}

trait A {
    fn clone(&self) -> Self;
}

impl A for i32 {
    fn clone(&self) -> i32 {
        self + 100
    }
}

impl A for u64 {
    fn clone(&self) -> u64 {
        self + 100
    }
}

#[derive(Educe)]
#[educe(Clone(bound = "T: std::clone::Clone, K: A"))]
enum Enum<T, K> {
    V1,
    V2 {
        #[educe(Clone(trait = "A"))]
        f1: K,
    },
    V3(
        T
    ),
}

Union

The #[educe(Clone)] attribute can be used for a union which also needs to implement the Copy trait. The fields of a union cannot be cloned with other methods or traits.

#[macro_use] extern crate educe;

#[derive(Educe)]
#[educe(Copy, Clone)]
union Union {
    f1: u8,
}

Copy

Use #[derive(Educe)] and #[educe(Copy)] to implement the Copy trait for a struct, an enum, or a union.

Basic Usage

#[macro_use] extern crate educe;

#[derive(Educe)]
#[educe(Copy, Clone)]
struct Struct {
    f1: u8
}

#[derive(Educe)]
#[educe(Copy, Clone)]
enum Enum {
    V1,
    V2 {
        f1: u8,
    },
    V3(u8),
}

Generic Parameters Bound to the Copy Trait or Others

The #[educe(Copy(bound))] attribute can be used to add the Copy trait bound to all generaic parameters for the Copy implementation.

#[macro_use] extern crate educe;

#[derive(Educe)]
#[educe(Copy(bound), Clone(bound))]
enum Enum<T, K> {
    V1,
    V2 {
        f1: K,
    },
    V3(
        T
    ),
}

Or you can set the where predicates by yourself.

#[macro_use] extern crate educe;

fn clone(v: &u8) -> u8 {
    v + 100
}

trait A {
    fn clone(&self) -> Self;
}

impl A for i32 {
    fn clone(&self) -> i32 {
        self + 100
    }
}

impl A for u64 {
    fn clone(&self) -> u64 {
        self + 100
    }
}

#[derive(Educe)]
#[educe(Copy(bound = "T: Copy, K: A + Copy"), Clone(bound = "T: Copy, K: A + Copy"))]
enum Enum<T, K> {
    V1,
    V2 {
        #[educe(Copy(trait = "A"))]
        f1: K,
    },
    V3(
        T
    ),
}

Copy and Clone

If you implement both of the Copy trait and the Clone trait by Educe, the bound for the Clone trait needs to include the Copy trait due to Copy, Clone optimization.

Deref

Use #[derive(Educe)] and #[educe(Deref)] to implement the Deref trait for a struct or an enum.

Basic Usage

You need to assign a field as a default inmutable dereferencing field unless the number of fields is exactly one.

#[macro_use] extern crate educe;

#[derive(Educe)]
#[educe(Deref)]
struct Struct {
    f1: u8,
    #[educe(Deref)]
    f2: u8,
}

#[derive(Educe)]
#[educe(Deref)]
enum Enum {
    Struct {
        f1: u8
    },
    Struct2 {
        f1: u8,
        #[educe(Deref)]
        f2: u8,
    },
    Tuple(u8),
    Tuple2(
        u8,
        #[educe(Deref)]
        u8
    ),
}

DerefMut

Use #[derive(Educe)] and #[educe(DerefMut)] to implement the DerefMut trait for a struct or an enum.

Basic Usage

You need to assign a field as a default mutable dereferencing field unless the number of fields is exactly one.

#[macro_use] extern crate educe;

#[derive(Educe)]
#[educe(Deref, DerefMut)]
struct Struct {
    f1: u8,
    #[educe(Deref, DerefMut)]
    f2: u8,
}

#[derive(Educe)]
#[educe(Deref, DerefMut)]
enum Enum {
    Struct {
        f1: u8
    },
    Struct2 {
        f1: u8,
        #[educe(Deref, DerefMut)]
        f2: u8,
    },
    Tuple(u8),
    Tuple2(
        #[educe(DerefMut)]
        u8,
        #[educe(Deref)]
        u8
    ),
}

The mutable dereferencing fields don't need to be the same as the inmutable dereferencing fields. But their type must be the same.

TODO

There is a lot of work to be done. Unimplemented traits are listed below:

  1. From
  2. Into
  3. FromStr
  4. TryFrom
  5. TryInto

Crates.io

https://crates.io/crates/educe

Documentation

https://docs.rs/educe

License

MIT

Dependencies

~0.7–1MB
~22K SLoC