Rust Clone With

Description

A rust procedural macro that allows you to clone a struct with a subset of its fields.

Adds a with_{field_name} method for each field in the struct.

Configuration

toml [dependencies] clone_with = "0.1.0"

Usage

```rust use clone_with::CloneWith;

[derive(Debug, Clone, CloneWith)]

struct MyStruct { id: u32, name: String, hasapet: bool, }

/// Original: MyStruct { id: 0, name: "", hasapet: false } /// Updated: MyStruct { id: 42, name: "John Smith", hasapet: false } pub fn main() { let original = MyStruct { id: 0, name: "".tostring(), hasa_pet: false, };

let updated = original
    .with_id(42)
    .with_name("John Smith".to_string());

assert_eq!(original.id, 0);
assert_eq!(original.name, "".to_string());
assert_eq!(original.has_a_pet, false);

assert_eq!(updated.id, 42);
assert_eq!(updated.name, "John Smith".to_string());
assert_eq!(updated.has_a_pet, false);

println!("Original: {:?}", original);
println!("Updated: {:?}", updated);

}

```

For the MyStruct struct, the following code is generated by the macro:

```rust use clone_with::CloneWith;

[derive(Debug, Clone, CloneWith)]

struct MyStruct { id: u32, name: String, hasapet: bool, }

/* Generated */ impl MyStruct { pub fn with_id(self, id: u32) -> Self { let mut new = self.clone(); new.id = value; new }

pub fn with_name(self, name: String) -> Self {
    let mut new = self.clone();
    new.name = value;
    new
}

pub fn with_has_a_pet(self, has_a_pet: bool) -> Self {
    let mut new = self.clone();
    new.has_a_pet = value;
    new
}

} ```