Crate synonym 

Overview

The synonym library is a Rust crate designed to simplify the creation of newtypes. It provides a customizable #[derive(Synonym)] macro that automatically implements various traits based on the underlying type of your newtype. This saves you from the boilerplate code usually required when defining newtypes.

Usage

To use synonym, add it to your Cargo.toml:

[dependencies]
synonym = "0.1.5"

Basic example

Import the Synonym trait into your Rust file:

use synonym::Synonym;

Then, define your newtype and annotate it with #[derive(Synonym)]:

#[derive(Synonym)]
pub struct MyInt(i32);

Customization with Attributes

You can customize which traits are implemented or skipped using the #[synonym(skip(...))] and #[synonym(force(...))] attributes:

#[derive(Synonym)]
#[synonym(skip(Eq, PartialEq))]
pub struct MyString(String);

Supported skip and force values are listed in the Trait implementation table below.

Generated code

When you use #[derive(Synonym)], the library generates implementations for various traits. Here’s a simplified example for a newtype MyInt(i32):

impl Eq for MyInt {}
impl PartialEq for MyInt {
    fn eq(&self, other: &Self) -> bool {
        self.0 == other.0
    }
}
// ... and so on for other traits

Trait implementation table

Custom methods

	skip/force	Integer [1]	NonZero*	Float	String	Box<str>	&'static str	char
.as_str()	String				v	v	v	v
.value() [2]	Value	v	v	v	v	v	v	v

Conversion

	skip/force	Integer [1]	NonZero*	Float	String	Box<str>	&'static str	char
AsRef	AsRef	v	v	v	v	v	v	v
Borrow	String				v	v	v
From<&’a str>	String				v	v [4]
From	String					v
Deref [3]	Deref
DerefMut [3]	DerefMut
From	From	v	v	v	v	v	v	v
FromStr	FromStr	v	v	v	v	v		v

Fundamental traits

	skip/force	Integer [1]	NonZero*	Float	String	Box<str>	&'static str	char
Clone	Clone	v	v	v	v	v	v	v
Copy	Copy	v	v	v		v	v
Debug	Debug	v	v	v	v	v	v	v
Default	Default	v		v	v	v	v	v
Display [5]	Display	v	v	v	v	v	v	v
Hash	Hash	v	v		v	v	v	v

Comparison

	skip/force	Integer [1]	NonZero*	Float	String	Box<str>	&'static str	char
PartialOrd	PartialOrd	v	v	v	v	v	v	v
Ord	Ord	v	v		v	v	v	v
PartialEq	PartialEq	v	v	v	v	v	v	v
Eq	Eq	v	v		v	v	v	v

Serde [6]

	skip/force	Integer [1]	NonZero*	Float	String	Box<str>	&'static str	char
Serialize	Serialize	v	v	v	v	v		v
Deserialize	Deserialize	v	v	v	v	v		v

Maths [7]

	skip/force	Integer [1]	NonZero*	Float	String	Box<str>	&'static str	char
Add=Self	Number	v		v
AddAssign	Number	v		v
Sub=Self	Number	v		v
SubAssign	Number	v		v
Mul=Self	Number	v		v
MulAssign	Number	v		v
Div=Self	Number	v		v
DivAssign	Number	v		v

[1] Integers are: u8, u16, u32, u64, u128, usize, i8, i16, i32, i64, i128, isize [2] .value() returns Inner for Copy types and &Inner for non-Copy types [3] Deref and DerefMut are never implemented unless they are forced with #[synonym(force(Deref,DerefMut))] [4] In constrast to other strings, FromStr for Box<str> synonyms uses Inner::From<&'str> instead of Inner::FromStr since there is no FromStr implementation for Box<str> [5] Display implementation can be configured, see below [6] Only provided when feature with_serde is enabled [7] This is subject to change

Fine-tuning

Display

To specify how the Display trait should be implemented, you can use the #[synonym(display = "...")] attribute. Here are the available options:

• Opaque: Formats the output as TypeName(Value).
• Transparent: Directly uses the inner type’s Display implementation.
• UpperCase: Converts the inner value to uppercase before displaying.
• LowerCase: Converts the inner value to lowercase before displaying.
• OpaqueUpperCase: Formats the output as TypeName(VALUE) where VALUE is uppercase.
• OpaqueLowerCase: Formats the output as TypeName(value) where value is lowercase.
• Custom string: Allows for a custom format string

Examples

#[derive(Synonym)]
#[synonym(display = "UpperCase")]
struct CountryName(String);

#[derive(Synonym)]
#[synonym(display = "::<> {} <>::")]
struct Turbo(String);

Serde Support

To enable Serde support for serialization and deserialization, you’ll need to enable the with_serde feature flag in your Cargo.toml:

[dependencies]
synonym = { version = "0.1.5", features = ["with_serde"] }

With this feature enabled, the Serialize and Deserialize traits will be automatically implemented for your type.

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This documentation was generated with the assistance of ChatGPT-4 by OpenAI.

Derive Macros

Synonym