Warning

This package is under construction, handle with care!

attrimpl

The aim of the package is to reduce boilerplate code by adding implementations in trivial cases.

Directives

Directives that can be added before fields

• from: implements From trait for the given type
• into: implements Into trait for the given type
• convert: adds both from and into directives for the given field
• deref: implements Deref trait for the given type
• deref_mut: implements Deref and DerefMut traits for the given type
• as_ref: implements AsRef trait for the given type
• as_mut: implements AsMut trait for the given type
• as: adds both as_ref and as_mut directives for the given field
• get_ref: adds a getter method for the field, a reference is returned
  • accepted params
    • name: specifies the name of the getter function, default value is <field_name> (e.g., get_ref(name = "foobar"))
• get_clone: adds a getter method for the field, the value is cloned
  • accepted params
    • name: specifies the name of the getter function, default value is <field_name> (e.g., get_clone(name = "foobar"))
• get_copy: adds a getter method for the field, the value is copied
  • accepted params
    • name: specifies the name of the getter function, default value is <field_name> (e.g., get_copy(name = "foobar"))
• get_mut: adds a mutable getter method for the field
  • accepted params
    • name: specifies the name of the getter function (<name>_mut), default value is <field_name>_mut (e.g., get_mut(name = "foobar"))
• access: adds both get_ref and get_mut directives for the given field
  • accepted params

    • name: specifies the name of both the getter and the get_mut function (e.g., access(name = "foobar"))

    • get_ref: specifies the type of the getter function, this is the default

    • get_clone: specifies the type of the getter function

    • get_copy: specifies the type of the getter function

Debugging

If the debug argument is added to the macro, then the generated code will be printed to stderr during compilation. Example:

#[attrimpl::attrimpl(debug)]
struct NamedStruct {
    #[attrimpl(from, into, deref_mut)]
    name: String,
}

Examples

Named struct (from, into, deref_mut):

#[attrimpl::attrimpl]
struct NamedStruct {
    #[attrimpl(from, into, deref_mut)]
    name: String,
}

// non-boxed
let mut value = NamedStruct::from("test".to_string());
value.push_str("ing");
let value: String = value.into();

// boxed
let mut value = Box::<NamedStruct>::from("test".to_string());
value.push_str("ing");
let value: String = (*value).into();

Named struct (into, as_ref, as_mut, get_ref, get_mut):

#[attrimpl::attrimpl]
struct NamedStruct {
    #[attrimpl(into)]
    #[attrimpl(as_ref, as_mut)]
    #[attrimpl(get_ref)]
    name: String,

    #[attrimpl(deref_mut)]
    #[attrimpl(access(name = "hobbyy"))]
    hobby: String,
}

let mut value = NamedStruct {
    name: "Jane Doe".to_string(),
    hobby: "rock climbing".to_string(),
};

// deref_mut
*value = "ice climbing".to_string();
// deref
assert_eq!(*value, "ice climbing");

// access(name = "hobbyy")
*value.hobbyy_mut() = "rock climbing".to_string();
assert_eq!(value.hobbyy(), "rock climbing");

// get_ref
assert_eq!(value.name(), "Jane Doe");

// as_ref
assert_eq!(value.as_ref(), "Jane Doe");
// as_mut
*value.as_mut() = "John Doe".to_string();
assert_eq!(value.as_ref(), "John Doe");

// into
let value: String = value.into();
assert_eq!(value, "John Doe");

Tuple struct:

#[attrimpl::attrimpl]
struct TupleStruct1(#[attrimpl(from, into, deref_mut)] String);

// non-boxed
let mut value = TupleStruct1::from("test".to_string());
value.push_str("ing");
let value: String = value.into();

// boxed
let mut value = Box::<TupleStruct1>::from("test".to_string());
value.push_str("ing");
let value: String = (*value).into();

Enum:

#[attrimpl::attrimpl]
enum Enum {
    S(#[attrimpl(convert)] String),
    U8 {
        #[attrimpl(from)]
        byte: u8,
    },
    F64(#[attrimpl(convert)] f64),
}

// non-boxed
let value = Enum::from("test".to_string());

// boxed
let value = Box::<Enum>::from("test".to_string());

Todo

• consider implementing from_boxed directive or (better) from(boxed) *

    {
        // from Box<String>
        let value = NamedStruct::from(Box::new("test".to_string()));
        assert_eq!(value.name, "test");
  
        // Boxed from Box<String>
        let value = Box::<NamedStruct>::from(Box::new("test".to_string()));
        assert_eq!(value.name, "test");
    }
    {
        // into Box<String>
        // Boxed into String
        // Boxed into Box<String>
    }
  

• accept only valid directives during parsing for the given item type (e.g., for enums no Deref or DerefMut should be accepted) (better error handling)
• handle errors in the package instead of relying on the Rust compiler where possible
• examine whether it is possible to implement deref, deref_mut, into, as_ref, as_mut on enums if every variant contains the same type
• #[attrimpl(from)] should work with multiple field structs and enums. Should be able to set the default values of the other fields (e.g., #[attrimpl(from(field_default | container_default))]).
• write test framework for compile time errors
• write a failing test where non-defined directive is given
• implement the following directives
  • #[attrimpl(display("asdasd {}"))]
  • not sure whether to implement that one: #[attrimpl(borrow)]
  • search for other possibilities of useful directives