css_parse/syntax/
component_value.rs

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

css_parse/syntax/
component_value.rs
