duplicate

Attribute macro for code duplication with substitution.

Motivation

If you find yourself in need of copying a block of code and then making some small changes to fit the new use case, this crate is for you.

The duplicate attribute macro will duplicate an item any number of times while inserting custom code in the designated places in each duplicate.

For an in-depth explanation of the syntax and features, see the documentation.

Example

```rust use duplicate::duplicate;

/// Trait we want to implement for u8, u16, and u32 trait IsMax { /// Returns true if self is its maximum possible value. fn is_max(&self) -> bool; }

[duplicate(

inttype maxvalue; [ u8 ] [ 255 ]; [ u16 ] [ 65535 ]; [ u32 ] [ 4294967295 ]; )] impl IsMax for inttype { fn ismax(&self) -> bool { *self == max_value } }

assert!(!42u8.ismax()); assert!(!42u16.ismax()); assert!(!42u32.is_max()); ``` Expands to:

```rust use duplicate::duplicate;

/// Trait we want to implement for u8, u16, and u32 trait IsMax { /// Returns true if self is its maximum possible value. fn is_max(&self) -> bool; }

impl IsMax for u8 { fn ismax(&self) -> bool { *self == 255 } } impl IsMax for u16 { fn ismax(&self) -> bool { *self == 65535 } } impl IsMax for u32 { fn ismax(&self) -> bool { *self == 4294967_295 } }

assert!(!42u8.ismax()); assert!(!42u16.ismax()); assert!(!42u32.is_max()); ```

Changelog

This project adheres to Semantic Versioning. During initial development (with versions 0.y.z), bumps to the minor version (y) signify breaking changes.

Added

• Short syntax now supports parameterized substitution. This allows identifiers to take arguments that can be used to customize the substitution for each use. See #5.

This changelog format is based on Keep a Changelog and shows only the changes since the previous version. See the full changelog for changes to all released versions.

License

<sup>Licensed under either of Apache License, Version 2.0 or MIT license at your option.</sup>