diff options
| -rw-r--r-- | src/doc/unstable-book/src/language-features/attr-literals.md | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/src/doc/unstable-book/src/language-features/attr-literals.md b/src/doc/unstable-book/src/language-features/attr-literals.md index 67eee214a4f..60741a74400 100644 --- a/src/doc/unstable-book/src/language-features/attr-literals.md +++ b/src/doc/unstable-book/src/language-features/attr-literals.md @@ -6,5 +6,25 @@ The tracking issue for this feature is: [#34981] ------------------------ +At present, literals are only accepted as the value of a key-value pair in +attributes. What's more, only _string_ literals are accepted. This means that +literals can only appear in forms of `#[attr(name = "value")]` or +`#[attr = "value"]`. +The `attr_literals` unstable feature allows other types of literals to be used +in attributes. Here are some examples of attributes that can now be used with +this feature enabled: + ++```rust,ignore ++#[attr] ++#[attr(true)] ++#[attr(ident)] ++#[attr(ident, 100, true, "true", ident = 100, ident = "hello", ident(100))] ++#[attr(100)] ++#[attr(enabled = true)] ++#[enabled(true)] ++#[attr("hello")] ++#[repr(C, align = 4)] ++#[repr(C, align(4))] ++``` |