rune 0.14.2

The Rune Language, an embeddable dynamic programming language for Rust.
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132

use crate::alloc::borrow::Cow;
use crate::ast::prelude::*;

#[test]
#[cfg(not(miri))]
fn ast_parse() {
    rt::<ast::ExprObject>("Foo {\"foo\": 42}");
    rt::<ast::ExprObject>("#{\"foo\": 42}");
    rt::<ast::ExprObject>("#{\"foo\": 42,}");

    rt::<ast::FieldAssign>("\"foo\": 42");
    rt::<ast::FieldAssign>("\"foo\": 42");
    rt::<ast::FieldAssign>("\"foo\": 42");

    rt::<ast::ObjectKey>("foo");
    rt::<ast::ObjectKey>("\"foo \\n bar\"");
}

/// An object expression.
///
/// * `#{ [field]* }`.
/// * `Object { [field]* }`.
#[derive(Debug, TryClone, PartialEq, Eq, Parse, ToTokens, Spanned)]
#[non_exhaustive]
pub struct ExprObject {
    /// Attributes associated with object.
    #[rune(iter, meta)]
    pub attributes: Vec<ast::Attribute>,
    /// An object identifier.
    #[rune(meta)]
    pub ident: ObjectIdent,
    /// Assignments in the object.
    pub assignments: ast::Braced<FieldAssign, T![,]>,
}

impl Peek for ExprObject {
    fn peek(p: &mut Peeker<'_>) -> bool {
        match (p.nth(0), p.nth(1)) {
            (K![ident], K!['{']) => true,
            (K![#], K!['{']) => true,
            _ => false,
        }
    }
}

/// A literal object identifier.
#[derive(Debug, TryClone, PartialEq, Eq, ToTokens, Spanned)]
#[non_exhaustive]
pub enum ObjectIdent {
    /// An anonymous object.
    Anonymous(T![#]),
    /// A named object.
    Named(ast::Path),
}

impl Parse for ObjectIdent {
    fn parse(p: &mut Parser<'_>) -> Result<Self> {
        Ok(match p.nth(0)? {
            K![#] => Self::Anonymous(p.parse()?),
            _ => Self::Named(p.parse()?),
        })
    }
}

/// A single field assignment in an object expression.
#[derive(Debug, TryClone, PartialEq, Eq, ToTokens, Spanned)]
#[non_exhaustive]
pub struct FieldAssign {
    /// The key of the field.
    pub key: ObjectKey,
    /// The assigned expression of the field.
    #[rune(iter)]
    pub assign: Option<(T![:], ast::Expr)>,
}

impl Parse for FieldAssign {
    fn parse(p: &mut Parser<'_>) -> Result<Self> {
        let key = p.parse()?;

        let assign = if p.peek::<T![:]>()? {
            let colon = p.parse()?;
            let expr = p.parse::<ast::Expr>()?;
            Some((colon, expr))
        } else {
            None
        };

        Ok(Self { key, assign })
    }
}

/// Possible literal object keys.
#[derive(Debug, TryClone, PartialEq, Eq, ToTokens, Spanned)]
#[non_exhaustive]
pub enum ObjectKey {
    /// A literal string (with escapes).
    LitStr(ast::LitStr),
    /// A path, usually an identifier.
    Path(ast::Path),
}

impl Parse for ObjectKey {
    fn parse(p: &mut Parser<'_>) -> Result<Self> {
        Ok(match p.nth(0)? {
            K![str] => Self::LitStr(p.parse()?),
            K![ident] => Self::Path(p.parse()?),
            _ => {
                return Err(compile::Error::expected(p.tok_at(0)?, "literal object key"));
            }
        })
    }
}

impl<'a> Resolve<'a> for ObjectKey {
    type Output = Cow<'a, str>;

    fn resolve(&self, cx: ResolveContext<'a>) -> Result<Self::Output> {
        Ok(match self {
            Self::LitStr(lit_str) => lit_str.resolve(cx)?,
            Self::Path(path) => {
                let ident = match path.try_as_ident() {
                    Some(ident) => ident,
                    None => {
                        return Err(compile::Error::expected(path, "object key"));
                    }
                };

                Cow::Borrowed(ident.resolve(cx)?)
            }
        })
    }
}