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use crate::ast;
use crate::{Parse, ParseError, Parser, Peek, Peeker, Spanned, ToTokens};
/// A use item.
///
/// # Examples
///
/// ```rust
/// use rune::{testing, ast};
///
/// testing::roundtrip::<ast::ItemUse>("use foo");
/// testing::roundtrip::<ast::ItemUse>("use foo::bar");
/// testing::roundtrip::<ast::ItemUse>("use foo::bar::baz");
/// testing::roundtrip::<ast::ItemUse>("#[macro_use] use foo::bar::baz");
/// testing::roundtrip::<ast::ItemUse>("#[macro_use] pub(crate) use foo::bar::baz");
/// ```
#[derive(Debug, Clone, PartialEq, Eq, Parse, ToTokens, Spanned)]
#[rune(parse = "meta_only")]
pub struct ItemUse {
/// The attributes on use item
#[rune(iter, meta)]
pub attributes: Vec<ast::Attribute>,
/// The visibility of the `use` item
#[rune(optional, meta)]
pub visibility: ast::Visibility,
/// The use token.
pub use_token: T![use],
/// Item path.
pub path: ItemUsePath,
}
item_parse!(Use, ItemUse, "use item");
/// A single use declaration path, like `foo::bar::{baz::*, biz}`.
///
/// # Examples
///
/// ```rust
/// use rune::{testing, ast};
///
/// testing::roundtrip::<ast::ItemUsePath>("crate::foo");
/// testing::roundtrip::<ast::ItemUsePath>("foo::bar");
/// testing::roundtrip::<ast::ItemUsePath>("foo::bar::{baz::*, biz}");
/// testing::roundtrip::<ast::ItemUsePath>("{*, bar::*}");
/// testing::roundtrip::<ast::ItemUsePath>("::{*, bar::*}");
/// ```
#[derive(Debug, Clone, PartialEq, Eq, Parse, ToTokens, Spanned)]
pub struct ItemUsePath {
/// Global prefix.
#[rune(iter)]
pub global: Option<T![::]>,
/// The first use component.
pub first: ItemUseSegment,
/// Optional segments.
#[rune(iter)]
pub segments: Vec<(T![::], ItemUseSegment)>,
/// The alias of the import.
#[rune(iter)]
pub alias: Option<(T![as], ast::Ident)>,
}
/// A use component.
#[derive(Debug, Clone, PartialEq, Eq, ToTokens, Spanned)]
pub enum ItemUseSegment {
/// A path segment.
PathSegment(ast::PathSegment),
/// A wildcard import.
Wildcard(T![*]),
/// A grouped import.
Group(ast::Braced<ast::ItemUsePath, T![,]>),
}
impl Peek for ItemUseSegment {
fn peek(p: &mut Peeker<'_>) -> bool {
matches!(p.nth(0), K![*] | K!['[']) || ast::PathSegment::peek(p)
}
}
impl Parse for ItemUseSegment {
fn parse(p: &mut Parser) -> Result<Self, ParseError> {
Ok(match p.nth(0)? {
K![*] => Self::Wildcard(p.parse()?),
K!['{'] => Self::Group(p.parse()?),
_ => Self::PathSegment(p.parse()?),
})
}
}