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use crate::ast;
use crate::{Id, OptionSpanned, Parse, ParseError, Parser, Spanned, ToTokens};
/// A struct item.
///
/// # Examples
///
/// ```rust
/// use rune::{testing, ast};
///
/// testing::roundtrip::<ast::ItemStruct>("struct Foo");
/// testing::roundtrip::<ast::ItemStruct>("struct Foo ( a, b, c )");
/// testing::roundtrip::<ast::ItemStruct>("struct Foo { a, b, c }");
/// testing::roundtrip::<ast::ItemStruct>("struct Foo { #[default_value = 1] a, b, c }");
/// testing::roundtrip::<ast::ItemStruct>("#[alpha] struct Foo ( #[default_value = \"x\" ] a, b, c )");
/// ```
#[derive(Debug, Clone, PartialEq, Eq, Parse, ToTokens, Spanned)]
#[rune(parse = "meta_only")]
pub struct ItemStruct {
/// Opaque identifier of the struct.
#[rune(id)]
pub id: Option<Id>,
/// The attributes for the struct
#[rune(iter, meta)]
pub attributes: Vec<ast::Attribute>,
/// The visibility of the `struct` item
#[rune(optional, meta)]
pub visibility: ast::Visibility,
/// The `struct` keyword.
pub struct_token: T![struct],
/// The identifier of the struct declaration.
pub ident: ast::Ident,
/// The body of the struct.
#[rune(optional)]
pub body: ItemStructBody,
}
impl ItemStruct {
/// If the struct declaration needs to be terminated with a semicolon.
pub fn needs_semi_colon(&self) -> bool {
self.body.needs_semi_colon()
}
}
item_parse!(Struct, ItemStruct, "struct item");
/// AST for a struct body.
#[derive(Debug, Clone, PartialEq, Eq, ToTokens, OptionSpanned)]
pub enum ItemStructBody {
/// An empty struct declaration.
UnitBody,
/// A tuple struct body.
TupleBody(ast::Parenthesized<Field, T![,]>),
/// A regular struct body.
StructBody(ast::Braced<Field, T![,]>),
}
impl ItemStructBody {
/// If the body needs to be terminated with a semicolon.
fn needs_semi_colon(&self) -> bool {
matches!(self, Self::UnitBody | Self::TupleBody(..))
}
/// Iterate over the fields of the body.
pub fn fields(&self) -> impl Iterator<Item = &'_ (Field, Option<T![,]>)> {
match self {
ItemStructBody::UnitBody => IntoIterator::into_iter(&[]),
ItemStructBody::TupleBody(body) => body.iter(),
ItemStructBody::StructBody(body) => body.iter(),
}
}
}
/// Parse implementation for a struct body.
///
/// # Examples
///
/// ```rust
/// use rune::{testing, ast};
///
/// testing::roundtrip::<ast::ItemStructBody>("");
///
/// testing::roundtrip::<ast::ItemStructBody>("{ a, b, c }");
/// testing::roundtrip::<ast::ItemStructBody>("{ #[x] a, #[y] b, #[z] #[w] #[f32] c }");
/// testing::roundtrip::<ast::ItemStructBody>("{ a, #[attribute] b, c }");
///
/// testing::roundtrip::<ast::ItemStructBody>("( a, b, c )");
/// testing::roundtrip::<ast::ItemStructBody>("( #[x] a, b, c )");
/// testing::roundtrip::<ast::ItemStructBody>("( #[x] pub a, b, c )");
/// testing::roundtrip::<ast::ItemStructBody>("( a, b, c )");
/// testing::roundtrip::<ast::ItemStructBody>("()");
/// ```
impl Parse for ItemStructBody {
fn parse(p: &mut Parser<'_>) -> Result<Self, ParseError> {
Ok(match p.nth(0)? {
K!['('] => Self::TupleBody(p.parse()?),
K!['{'] => Self::StructBody(p.parse()?),
_ => Self::UnitBody,
})
}
}
/// A field as part of a struct or a tuple body.
///
/// # Examples
///
/// ```rust
/// use rune::{testing, ast};
///
/// testing::roundtrip::<ast::Field>("a");
/// testing::roundtrip::<ast::Field>("#[x] a");
/// ```
#[derive(Debug, Clone, PartialEq, Eq, ToTokens, Parse, Spanned)]
pub struct Field {
/// Attributes associated with field.
#[rune(iter)]
pub attributes: Vec<ast::Attribute>,
/// The visibility of the field
#[rune(optional)]
pub visibility: ast::Visibility,
/// Name of the field.
pub name: ast::Ident,
}