css_parse/syntax/
component_value.rs

1use super::prelude::*;
2use crate::{AssociatedWhitespaceRules, FunctionBlock, Result, SimpleBlock};
3
4/// <https://drafts.csswg.org/css-syntax-3/#consume-component-value>
5///
6/// A compatible "Token" per CSS grammar, subsetted to the tokens possibly
7/// rendered by ComponentValue (so no pairwise, function tokens, etc).
8#[node]
9#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
10#[cfg_attr(feature = "serde", derive(serde::Serialize), serde(untagged))]
11pub enum ComponentValue<'a> {
12	SimpleBlock(SimpleBlock<'a>),
13	Function(FunctionBlock<'a>),
14	Whitespace(T![Whitespace]),
15	Number(T![Number]),
16	Dimension(T![Dimension]),
17	Ident(T![Ident]),
18	AtKeyword(T![AtKeyword]),
19	Hash(T![Hash]),
20	String(T![String]),
21	Url(T![Url]),
22	Delim(T![Delim]),
23	Colon(T![:]),
24	Semicolon(T![;]),
25	Comma(T![,]),
26}
27
28impl<'a, M: NodeMetadata> NodeWithMetadata<M> for ComponentValue<'a> {
29	fn metadata(&self) -> M {
30		M::default()
31	}
32}
33
34impl<'a> Peek<'a> for ComponentValue<'a> {
35	const PEEK_KINDSET: KindSet = KindSet::new(&[
36		Kind::Whitespace,
37		Kind::Number,
38		Kind::Dimension,
39		Kind::Ident,
40		Kind::AtKeyword,
41		Kind::Hash,
42		Kind::String,
43		Kind::Url,
44		Kind::Delim,
45		Kind::Colon,
46		Kind::Semicolon,
47		Kind::Comma,
48		Kind::Function,
49		Kind::LeftCurly,
50		Kind::LeftParen,
51		Kind::LeftSquare,
52	]);
53	#[inline(always)]
54	fn peek<Iter>(p: &Parser<'a, Iter>, c: Cursor) -> bool
55	where
56		Iter: Iterator<Item = Cursor> + Clone,
57	{
58		c == Self::PEEK_KINDSET || <T![' ']>::peek(p, c)
59	}
60}
61
62// https://drafts.csswg.org/css-syntax-3/#consume-component-value
63impl<'a> Parse<'a> for ComponentValue<'a> {
64	fn parse<Iter>(p: &mut Parser<'a, Iter>) -> Result<Self>
65	where
66		Iter: Iterator<Item = Cursor> + Clone,
67	{
68		let c = p.peek_n(1);
69		Ok(if <T![' ']>::peek(p, c) {
70			Self::Whitespace(p.parse::<T![' ']>()?)
71		} else if <T![PairWiseStart]>::peek(p, c) {
72			let old_state = p.set_state(State::Nested);
73			let block = p.parse::<SimpleBlock>();
74			p.set_state(old_state);
75			Self::SimpleBlock(block?)
76		} else if <T![Function]>::peek(p, c) {
77			Self::Function(p.parse::<FunctionBlock>()?)
78		} else if <T![Number]>::peek(p, c) {
79			Self::Number(p.parse::<T![Number]>()?)
80		} else if <T![Dimension]>::peek(p, c) {
81			Self::Dimension(p.parse::<T![Dimension]>()?)
82		} else if <T![Ident]>::peek(p, c) {
83			Self::Ident(p.parse::<T![Ident]>()?)
84		} else if <T![AtKeyword]>::peek(p, c) {
85			Self::AtKeyword(p.parse::<T![AtKeyword]>()?)
86		} else if <T![Hash]>::peek(p, c) {
87			Self::Hash(p.parse::<T![Hash]>()?)
88		} else if <T![String]>::peek(p, c) {
89			Self::String(p.parse::<T![String]>()?)
90		} else if <T![Url]>::peek(p, c) {
91			Self::Url(p.parse::<T![Url]>()?)
92		} else if <T![Delim]>::peek(p, c) {
93			p.parse::<T![Delim]>().map(|delim| {
94				// Carefully handle Whitespace rules to ensure whitespace isn't lost when re-serializing
95				let mut rules = AssociatedWhitespaceRules::none();
96				if p.peek_n_with_skip(1, KindSet::COMMENTS) == Kind::Whitespace {
97					rules |= AssociatedWhitespaceRules::EnforceAfter;
98				} else {
99					rules |= AssociatedWhitespaceRules::BanAfter;
100				}
101				Self::Delim(delim.with_associated_whitespace(rules))
102			})?
103		} else if <T![:]>::peek(p, c) {
104			Self::Colon(p.parse::<T![:]>()?)
105		} else if <T![;]>::peek(p, c) {
106			Self::Semicolon(p.parse::<T![;]>()?)
107		} else if <T![,]>::peek(p, c) {
108			Self::Comma(p.parse::<T![,]>()?)
109		} else {
110			Err(Diagnostic::new(p.next(), Diagnostic::unexpected))?
111		})
112	}
113}
114
115impl<'a> ToCursors for ComponentValue<'a> {
116	fn to_cursors(&self, s: &mut impl CursorSink) {
117		match self {
118			Self::SimpleBlock(t) => ToCursors::to_cursors(t, s),
119			Self::Function(t) => ToCursors::to_cursors(t, s),
120			Self::Ident(t) => ToCursors::to_cursors(t, s),
121			Self::AtKeyword(t) => ToCursors::to_cursors(t, s),
122			Self::Hash(t) => ToCursors::to_cursors(t, s),
123			Self::String(t) => ToCursors::to_cursors(t, s),
124			Self::Url(t) => ToCursors::to_cursors(t, s),
125			Self::Delim(t) => ToCursors::to_cursors(t, s),
126			Self::Number(t) => ToCursors::to_cursors(t, s),
127			Self::Dimension(t) => ToCursors::to_cursors(t, s),
128			Self::Whitespace(t) => ToCursors::to_cursors(t, s),
129			Self::Colon(t) => ToCursors::to_cursors(t, s),
130			Self::Semicolon(t) => ToCursors::to_cursors(t, s),
131			Self::Comma(t) => ToCursors::to_cursors(t, s),
132		}
133	}
134}
135
136impl<'a> ToSpan for ComponentValue<'a> {
137	fn to_span(&self) -> Span {
138		match self {
139			Self::SimpleBlock(t) => t.to_span(),
140			Self::Function(t) => t.to_span(),
141			Self::Ident(t) => t.to_span(),
142			Self::AtKeyword(t) => t.to_span(),
143			Self::Hash(t) => t.to_span(),
144			Self::String(t) => t.to_span(),
145			Self::Url(t) => t.to_span(),
146			Self::Delim(t) => t.to_span(),
147			Self::Number(t) => t.to_span(),
148			Self::Dimension(t) => t.to_span(),
149			Self::Whitespace(t) => t.to_span(),
150			Self::Colon(t) => t.to_span(),
151			Self::Semicolon(t) => t.to_span(),
152			Self::Comma(t) => t.to_span(),
153		}
154	}
155}
156
157impl<'a> SemanticEq for ComponentValue<'a> {
158	fn semantic_eq(&self, other: &Self) -> bool {
159		match (self, other) {
160			(Self::SimpleBlock(a), Self::SimpleBlock(b)) => a.semantic_eq(b),
161			(Self::Function(a), Self::Function(b)) => a.semantic_eq(b),
162			(Self::Number(a), Self::Number(b)) => a.semantic_eq(b),
163			(Self::Dimension(a), Self::Dimension(b)) => a.semantic_eq(b),
164			(Self::Ident(a), Self::Ident(b)) => a.semantic_eq(b),
165			(Self::AtKeyword(a), Self::AtKeyword(b)) => a.semantic_eq(b),
166			(Self::Hash(a), Self::Hash(b)) => a.semantic_eq(b),
167			(Self::String(a), Self::String(b)) => a.semantic_eq(b),
168			(Self::Url(a), Self::Url(b)) => a.semantic_eq(b),
169			(Self::Delim(a), Self::Delim(b)) => a.semantic_eq(b),
170			(Self::Colon(a), Self::Colon(b)) => a.semantic_eq(b),
171			(Self::Semicolon(a), Self::Semicolon(b)) => a.semantic_eq(b),
172			(Self::Comma(a), Self::Comma(b)) => a.semantic_eq(b),
173			// Whitespace has no semantic relevance, other than its presence, so it should always be true
174			(Self::Whitespace(_), Self::Whitespace(_)) => true,
175			_ => false, // Different variants are never equal
176		}
177	}
178}
179
180#[cfg(test)]
181mod tests {
182	use super::*;
183	use crate::{EmptyAtomSet, test_helpers::*};
184
185	#[test]
186	fn test_writes() {
187		assert_parse!(EmptyAtomSet::ATOMS, ComponentValue, "foo");
188		assert_parse!(EmptyAtomSet::ATOMS, ComponentValue, " ");
189		assert_parse!(EmptyAtomSet::ATOMS, ComponentValue, "{block}");
190	}
191}
css_parse/syntax/component_value.rs

css_parse/syntax/
component_value.rs
