moxy_token/
group.rs

1use crate::lex::{Cursor, LexError, Scan};
2use crate::span::DelimSpan;
3use crate::{Delim, Span, TokenStream, TokenTree};
4
5/// A delimited sequence of token trees.
6#[derive(Debug, Clone, PartialEq, Eq)]
7pub struct Group {
8    pub delim: Delim,
9    pub span: DelimSpan,
10    pub tokens: TokenStream,
11}
12
13impl Group {
14    #[inline]
15    pub fn new(delim: Delim, stream: TokenStream) -> Self {
16        Self {
17            delim,
18            span: DelimSpan::new(Span::call_site(), Span::call_site()),
19            tokens: stream,
20        }
21    }
22
23    #[inline]
24    pub fn to_token_tree(&self) -> TokenTree {
25        TokenTree::Group(self.clone())
26    }
27
28    #[inline]
29    pub fn into_token_tree(self) -> TokenTree {
30        TokenTree::Group(self)
31    }
32}
33
34impl std::fmt::Display for Group {
35    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
36        match self.delim {
37            Delim::None => write!(f, "{}", self.tokens),
38            d => write!(f, "{}{}{}", d.open(), self.tokens, d.close()),
39        }
40    }
41}
42
43impl Scan for Group {
44    fn scan(cursor: Cursor<'_>) -> Result<(Cursor<'_>, Self), LexError> {
45        let ch = cursor.first().ok_or(cursor.error())?;
46        let delim = Delim::from_open(ch).ok_or(cursor.error())?;
47        let c = cursor.advance_by(ch.len_utf8());
48        let (c, inner) = TokenStream::scan(c)?;
49        let close_ch = c
50            .first()
51            .ok_or_else(|| cursor.error().message(format!("unclosed delimiter '{}'", delim.open())))?;
52
53        let close_delim = Delim::from_close(close_ch).ok_or_else(|| {
54            c.error()
55                .message(format!("expected '{}', found '{}'", delim.close(), close_ch))
56        })?;
57
58        if delim != close_delim {
59            return Err(c.error().message(format!(
60                "mismatched delimiter: expected '{}', found '{}'",
61                delim.close(),
62                close_ch,
63            )));
64        }
65
66        let c = c.advance_by(close_ch.len_utf8());
67        let mut group = Self::new(delim, inner);
68        group.span = DelimSpan::new(cursor.span(), c.span());
69
70        Ok((c, group))
71    }
72}
73
74impl crate::ToTokens for Group {
75    fn to_tokens(&self, tokens: &mut crate::TokenStream) {
76        tokens.extend_one(crate::TokenTree::Group(self.clone()));
77    }
78}
79
80impl crate::Spanner for Group {
81    fn span(&self) -> Span {
82        self.span.span()
83    }
84}
85
86#[cfg(feature = "serde")]
87impl serde::Serialize for Group {
88    fn serialize<S>(&self, s: S) -> Result<S::Ok, S::Error>
89    where
90        S: serde::Serializer,
91    {
92        use serde::ser::SerializeStruct;
93
94        let mut o = s.serialize_struct("Group", 2)?;
95        o.serialize_field("delim", &self.delim)?;
96        o.serialize_field("tokens", &self.tokens)?;
97        o.end()
98    }
99}
moxy_token/group.rs

moxy_token/
group.rs
