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