css_parse/syntax/
no_block_allowed.rs

1use crate::{CursorSink, Diagnostic, KindSet, Parse, Parser, Peek, Result, SemanticEq, Span, T, ToCursors, ToSpan};
2use csskit_proc_macro::node;
3
4/// A struct to provide to rules to disallow blocks.
5///
6/// Sometimes a rule will not allow a block - for example `@charset`, `@import`. In those case, assigning this struct
7/// to the `Block` can be useful to ensure that the [QualifiedRule][crate::syntax::QualifiedRule] appropriately errors
8/// if it enters the Block parsing context. This captures the `;` token that may optionally end a "statement-style"
9/// at-rule.
10///
11/// The phantom data allows this type to be compatible with different declaration value and metadata types,
12/// even though it doesn't actually use them (since no block is allowed).
13#[node]
14#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
15#[cfg_attr(feature = "serde", derive(serde::Serialize), serde())]
16pub struct NoBlockAllowed<D = (), M = ()> {
17	semicolon: Option<crate::token_macros::Semicolon>,
18	_phantom: std::marker::PhantomData<(D, M)>,
19}
20
21impl<'a, D, M> Parse<'a> for NoBlockAllowed<D, M> {
22	fn parse<Iter>(p: &mut Parser<'a, Iter>) -> Result<Self>
23	where
24		Iter: Iterator<Item = crate::Cursor> + Clone,
25	{
26		if p.at_end() {
27			Ok(Self { semicolon: None, _phantom: std::marker::PhantomData })
28		} else if let Some(semicolon) = p.parse_if_peek::<T![;]>()? {
29			Ok(Self { semicolon: Some(semicolon), _phantom: std::marker::PhantomData })
30		} else {
31			Err(Diagnostic::new(p.next(), Diagnostic::unexpected))?
32		}
33	}
34}
35
36impl<'a, D, M> Peek<'a> for NoBlockAllowed<D, M> {
37	const PEEK_KINDSET: KindSet = KindSet::NONE;
38}
39
40impl<D, M> ToCursors for NoBlockAllowed<D, M> {
41	fn to_cursors(&self, s: &mut impl CursorSink) {
42		if let Some(semicolon) = self.semicolon {
43			s.append(semicolon.into());
44		}
45	}
46}
47
48impl<D, M> ToSpan for NoBlockAllowed<D, M> {
49	fn to_span(&self) -> Span {
50		self.semicolon.to_span()
51	}
52}
53
54impl<D, M> SemanticEq for NoBlockAllowed<D, M> {
55	fn semantic_eq(&self, other: &Self) -> bool {
56		self.semicolon.semantic_eq(&other.semicolon)
57	}
58}
59
60impl<D, M: crate::NodeMetadata> crate::NodeWithMetadata<M> for NoBlockAllowed<D, M> {
61	fn metadata(&self) -> M {
62		M::default()
63	}
64}
65
66impl<'a, D, M> crate::RuleVariants<'a> for NoBlockAllowed<D, M>
67where
68	D: crate::DeclarationValue<'a, M>,
69	M: crate::NodeMetadata,
70{
71	type DeclarationValue = D;
72	type Metadata = M;
73}
css_parse/syntax/no_block_allowed.rs

css_parse/syntax/
no_block_allowed.rs
