Crate enum_methods

enum-methods

Enum getter/is_XXX method generation.

Usage

In your Cargo.toml, add this line under your [dependencies] section:

enum-methods = "0.0.1"

To use, simply derive and call methods (see the example below).

Why?

Usually when you write an enum with one or zero values, you might want to add a set of getters for them. As such:

#[derive(Debug)]
enum MyEnum {
    Foo(i64),
    Bar(char),
    Baz(String),
}

impl MyEnum {
    pub fn foo(&self) -> i64 {
        if let &MyEnum::Foo(i) = self {
            i
        }
        else {
            panic!("called MyEnum::Foo() on {:?}", self)
        }
    }
    // et cetera
}

But this gets tedious, and adds a lot code for this simple functionality. Enter enum-methods.

Instead of doing the above with the if let ... else { panic!(...) }, you simply derive from the EnumGetters ```

[derive(EnumGetters, Debug)]

enum MyEnum { Foo(i64), Bar(char), Baz(String), }

fn main() { let foo = MyEnum::foo(42); assert_eq!(foo.foo(), 42); // success! } ```

Requirements and gotchas

Right now, enum-methods has only two derivable options: * EnumGetters * EnumIsA

EnumGetters has a couple of limitations. First, each enum variant must have exactly 0 or 1 members. Enum variants with 0 members do not get a method generated for it. Generated methods simply use the lower-case version of their variant name. These names are not converated to snake_case. Additionally, enums which derive from EnumGetters must also derive from Debug - this is for when a method is called for the wrong variant and needs to panic!.

EnumIsA is much simpler than the previous; it simply adds is_XXX methods returning a boolean for whether the variant matches or not. Similar to EnumGetters, the name is converted to lowercase and does not convert to snake_case.

License

This software is released under the Apache license 2.0. See the LICENSE file for more details.

Functions

enum_getters
enum_is_a