rune/ast/
expr_closure.rs

1use crate::ast::prelude::*;
2
3#[test]
4#[cfg(not(miri))]
5fn ast_parse() {
6    rt::<ast::ExprClosure>("async || 42");
7    rt::<ast::ExprClosure>("|| 42");
8    rt::<ast::ExprClosure>("|| { 42 }");
9    rt::<ast::ExprClosure>("move || { 42 }");
10    rt::<ast::ExprClosure>("async move || { 42 }");
11
12    let expr = rt::<ast::ExprClosure>("#[retry(n=3)]  || 43");
13    assert_eq!(expr.attributes.len(), 1);
14
15    let expr = rt::<ast::ExprClosure>("#[retry(n=3)] async || 43");
16    assert_eq!(expr.attributes.len(), 1);
17}
18
19/// A closure expression.
20///
21/// * `|| <expr>`.
22/// * `async || <expr>`.
23#[derive(Debug, TryClone, PartialEq, Eq, Parse, ToTokens, Spanned)]
24#[rune(parse = "meta_only")]
25#[non_exhaustive]
26pub struct ExprClosure {
27    /// The attributes for the async closure
28    #[rune(iter, meta)]
29    pub attributes: Vec<ast::Attribute>,
30    /// If the closure is async or not.
31    #[rune(iter, meta)]
32    pub async_token: Option<T![async]>,
33    /// If the closure moves data into it.
34    #[rune(iter, meta)]
35    pub move_token: Option<T![move]>,
36    /// Arguments to the closure.
37    pub args: ExprClosureArgs,
38    /// The body of the closure.
39    pub body: Box<ast::Expr>,
40    /// Opaque identifier for the closure.
41    #[rune(skip)]
42    pub(crate) id: ItemId,
43}
44
45impl ExprClosure {
46    /// Get the identifying span for this closure.
47    pub fn item_span(&self) -> Span {
48        if let Some(async_) = &self.async_token {
49            async_.span().join(self.args.span())
50        } else {
51            self.args.span()
52        }
53    }
54}
55
56expr_parse!(Closure, ExprClosure, "closure expression");
57
58/// Representation of closure arguments.
59#[derive(Debug, TryClone, PartialEq, Eq, ToTokens)]
60#[non_exhaustive]
61pub enum ExprClosureArgs {
62    /// Closure has no arguments.
63    Empty {
64        /// The `||` token.
65        token: T![||],
66    },
67    /// Closure has a list of arguments.
68    List {
69        /// The opening pipe for the argument group.
70        open: T![|],
71        /// The arguments of the function.
72        args: Vec<(ast::FnArg, Option<T![,]>)>,
73        /// The closening pipe for the argument group.
74        close: T![|],
75    },
76}
77
78impl ExprClosureArgs {}
79
80impl Parse for ExprClosureArgs {
81    fn parse(p: &mut Parser<'_>) -> Result<Self> {
82        if let Some(token) = p.parse::<Option<T![||]>>()? {
83            return Ok(ExprClosureArgs::Empty { token });
84        }
85
86        let open = p.parse()?;
87        let mut args = Vec::new();
88
89        while !p.peek::<T![|]>()? {
90            let arg = p.parse()?;
91
92            let comma = p.parse::<Option<T![,]>>()?;
93            let is_end = comma.is_none();
94            args.try_push((arg, comma))?;
95
96            if is_end {
97                break;
98            }
99        }
100
101        Ok(ExprClosureArgs::List {
102            open,
103            args,
104            close: p.parse()?,
105        })
106    }
107}
108
109impl Spanned for ExprClosureArgs {
110    fn span(&self) -> Span {
111        match self {
112            Self::Empty { token } => token.span(),
113            Self::List { open, close, .. } => open.span().join(close.span()),
114        }
115    }
116}
rune/ast/expr_closure.rs

rune/ast/
expr_closure.rs
