fac9ee5f86
This PR adds the `ui_macros` crate to allow building supporting macros
for the `ui` crate.
Additionally, it implements the `DerivePathStr` derive macro and the
`path_str` attribute macro. These macros work together to generate a
`path` method for enum variants, which is useful for creating
standardized string representations of enum variants.
The `DerivePathStr` macro provides the following functionality:
- Generates a `path` method for each enum variant.
- Allows specifying a prefix (required) and suffix (optional) for all
paths.
- Supports `strum` attributes for case conversion (e.g., snake_case,
lowercase).
Usage example:
```rust
#[derive(DerivePathStr)]
#[path_str(prefix = "my_prefix", suffix = ".txt")]
#[strum(serialize_all = "snake_case")]
enum MyEnum {
VariantOne,
VariantTwo,
}
// Generated paths:
// MyEnum::VariantOne.path() -> "my_prefix/variant_one.txt"
// MyEnum::VariantTwo.path() -> "my_prefix/variant_two.txt"
```
In a later PR this will be used to automate the creation of icon & image
paths in the `ui` crate.
This gives the following benefits:
1. Ensures standard naming of assets as paths are not manually
specified.
2. Makes adding new enum variants less tedious and error-prone.
3. Quickly catches missing or incorrect paths during compilation.
3. Adds a building block towards being able to lint for unused assets in
the future.
Release Notes:
- N/A
53 lines
1.8 KiB
Rust
53 lines
1.8 KiB
Rust
mod derive_path_str;
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use proc_macro::TokenStream;
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/// Derives the `path` method for an enum.
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///
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/// This macro generates a `path` method for each variant of the enum, which returns a string
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/// representation of the enum variant's path. The path is constructed using a prefix and
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/// optionally a suffix, which are specified using attributes.
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///
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/// # Attributes
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///
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/// - `#[path_str(prefix = "...")]`: Required. Specifies the prefix for all paths.
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/// - `#[path_str(suffix = "...")]`: Optional. Specifies a suffix for all paths.
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/// - `#[strum(serialize_all = "...")]`: Optional. Specifies the case conversion for variant names.
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///
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/// # Example
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///
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/// ```
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/// use strum::EnumString;
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/// use ui_macros::{path_str, DerivePathStr};
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///
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/// #[derive(EnumString, DerivePathStr)]
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/// #[path_str(prefix = "my_prefix", suffix = ".txt")]
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/// #[strum(serialize_all = "snake_case")]
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/// enum MyEnum {
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/// VariantOne,
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/// VariantTwo,
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/// }
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///
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/// // These assertions would work if we could instantiate the enum
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/// // assert_eq!(MyEnum::VariantOne.path(), "my_prefix/variant_one.txt");
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/// // assert_eq!(MyEnum::VariantTwo.path(), "my_prefix/variant_two.txt");
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/// ```
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///
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/// # Panics
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///
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/// This macro will panic if used on anything other than an enum.
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#[proc_macro_derive(DerivePathStr, attributes(path_str))]
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pub fn derive_path_str(input: TokenStream) -> TokenStream {
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derive_path_str::derive_path_str(input)
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}
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/// A marker attribute for use with `DerivePathStr`.
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///
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/// This attribute is used to specify the prefix and suffix for the `path` method
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/// generated by `DerivePathStr`. It doesn't modify the input and is only used as a
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/// marker for the derive macro.
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#[proc_macro_attribute]
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pub fn path_str(_args: TokenStream, input: TokenStream) -> TokenStream {
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// This attribute doesn't modify the input, it's just a marker
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input
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}
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