//! # Documentation for Additional Attributes //! //! ## Attributes on Enums //! //! Strum supports several custom attributes to modify the generated code. At the enum level, the following attributes are supported: //! //! - `#[strum(serialize_all = "case_style")]` attribute can be used to change the case used when serializing to and deserializing //! from strings. This feature is enabled by [withoutboats/heck](https://github.com/withoutboats/heck) and supported case styles are: //! //! - `camelCase` //! - `PascalCase` //! - `kebab-case` //! - `snake_case` //! - `SCREAMING_SNAKE_CASE` //! - `SCREAMING-KEBAB-CASE` //! - `lowercase` //! - `UPPERCASE` //! - `title_case` //! - `mixed_case` //! //! ```rust //! use std::string::ToString; //! use strum; //! use strum_macros; //! //! #[derive(Debug, Eq, PartialEq, strum_macros::ToString)] //! #[strum(serialize_all = "snake_case")] //! enum Brightness { //! DarkBlack, //! Dim { //! glow: usize, //! }, //! #[strum(serialize = "bright")] //! BrightWhite, //! } //! //! assert_eq!( //! String::from("dark_black"), //! Brightness::DarkBlack.to_string().as_ref() //! ); //! assert_eq!( //! String::from("dim"), //! Brightness::Dim { glow: 0 }.to_string().as_ref() //! ); //! assert_eq!( //! String::from("bright"), //! Brightness::BrightWhite.to_string().as_ref() //! ); //! ``` //! //! - You can also apply the `#[strum(ascii_case_insensitive)]` attribute to the enum, //! and this has the same effect of applying it to every variant. //! //! ## Attributes on Variants //! //! Custom attributes are applied to a variant by adding `#[strum(parameter="value")]` to the variant. //! //! - `serialize="..."`: Changes the text that `FromStr()` looks for when parsing a string. This attribute can //! be applied multiple times to an element and the enum variant will be parsed if any of them match. //! //! - `to_string="..."`: Similar to `serialize`. This value will be included when using `FromStr()`. More importantly, //! this specifies what text to use when calling `variant.to_string()` with the `Display` derivation, or when calling `variant.as_ref()` with `AsRefStr`. //! //! - `default`: Applied to a single variant of an enum. The variant must be a Tuple-like //! variant with a single piece of data that can be create from a `&str` i.e. `T: From<&str>`. //! The generated code will now return the variant with the input string captured as shown below //! instead of failing. //! //! ```text //! // Replaces this: //! _ => Err(strum::ParseError::VariantNotFound) //! // With this in generated code: //! default => Ok(Variant(default.into())) //! ``` //! The plugin will fail if the data doesn't implement From<&str>. You can only have one `default` //! on your enum. //! //! - `disabled`: removes variant from generated code. //! //! - `ascii_case_insensitive`: makes the comparison to this variant case insensitive (ASCII only). //! If the whole enum is marked `ascii_case_insensitive`, you can specify `ascii_case_insensitive = false` //! to disable case insensitivity on this v ariant. //! //! - `message=".."`: Adds a message to enum variant. This is used in conjunction with the `EnumMessage` //! trait to associate a message with a variant. If `detailed_message` is not provided, //! then `message` will also be returned when `get_detailed_message` is called. //! //! - `detailed_message=".."`: Adds a more detailed message to a variant. If this value is omitted, then //! `message` will be used in it's place. //! //! - Structured documentation, as in `/// ...`: If using `EnumMessage`, is accessible via get_documentation(). //! //! - `props(key="value")`: Enables associating additional information with a given variant.