1//! # Documentation for Additional Attributes
2//!
3//! ## Attributes on Enums
4//!
5//! Strum supports several custom attributes to modify the generated code. At the enum level, the following attributes are supported:
6//!
7//! - `#[strum(serialize_all = "case_style")]` attribute can be used to change the case used when serializing to and deserializing
8//! from strings. This feature is enabled by [withoutboats/heck](https://github.com/withoutboats/heck) and supported case styles are:
9//!
10//! - `camelCase`
11//! - `PascalCase`
12//! - `kebab-case`
13//! - `snake_case`
14//! - `SCREAMING_SNAKE_CASE`
15//! - `SCREAMING-KEBAB-CASE`
16//! - `lowercase`
17//! - `UPPERCASE`
18//! - `title_case`
19//! - `mixed_case`
20//! - `Train-Case`
21//!
22//! ```rust
23//! use strum_macros;
24//!
25//! #[derive(Debug, Eq, PartialEq, strum_macros::Display)]
26//! #[strum(serialize_all = "snake_case")]
27//! enum Brightness {
28//! DarkBlack,
29//! Dim {
30//! glow: usize,
31//! },
32//! #[strum(serialize = "bright")]
33//! BrightWhite,
34//! }
35//!
36//! assert_eq!(
37//! String::from("dark_black"),
38//! Brightness::DarkBlack.to_string().as_ref()
39//! );
40//! assert_eq!(
41//! String::from("dim"),
42//! Brightness::Dim { glow: 0 }.to_string().as_ref()
43//! );
44//! assert_eq!(
45//! String::from("bright"),
46//! Brightness::BrightWhite.to_string().as_ref()
47//! );
48//! ```
49//!
50//! - You can also apply the `#[strum(ascii_case_insensitive)]` attribute to the enum,
51//! and this has the same effect of applying it to every variant.
52//!
53//! ## Attributes on Variants
54//!
55//! Custom attributes are applied to a variant by adding `#[strum(parameter="value")]` to the variant.
56//!
57//! - `serialize="..."`: Changes the text that `FromStr()` looks for when parsing a string. This attribute can
58//! be applied multiple times to an element and the enum variant will be parsed if any of them match.
59//!
60//! - `to_string="..."`: Similar to `serialize`. This value will be included when using `FromStr()`. More importantly,
61//! this specifies what text to use when calling `variant.to_string()` with the `Display` derivation, or when calling `variant.as_ref()` with `AsRefStr`.
62//!
63//! - `default`: Applied to a single variant of an enum. The variant must be a Tuple-like
64//! variant with a single piece of data that can be create from a `&str` i.e. `T: From<&str>`.
65//! The generated code will now return the variant with the input string captured as shown below
66//! instead of failing.
67//!
68//! ```text
69//! // Replaces this:
70//! _ => Err(strum::ParseError::VariantNotFound)
71//! // With this in generated code:
72//! default => Ok(Variant(default.into()))
73//! ```
74//! The plugin will fail if the data doesn't implement From<&str>. You can only have one `default`
75//! on your enum.
76//!
77//! - `disabled`: removes variant from generated code.
78//!
79//! - `ascii_case_insensitive`: makes the comparison to this variant case insensitive (ASCII only).
80//! If the whole enum is marked `ascii_case_insensitive`, you can specify `ascii_case_insensitive = false`
81//! to disable case insensitivity on this v ariant.
82//!
83//! - `message=".."`: Adds a message to enum variant. This is used in conjunction with the `EnumMessage`
84//! trait to associate a message with a variant. If `detailed_message` is not provided,
85//! then `message` will also be returned when `get_detailed_message` is called.
86//!
87//! - `detailed_message=".."`: Adds a more detailed message to a variant. If this value is omitted, then
88//! `message` will be used in it's place.
89//!
90//! - Structured documentation, as in `/// ...`: If using `EnumMessage`, is accessible via get_documentation().
91//!
92//! - `props(key="value")`: Enables associating additional information with a given variant.
93