css_parse/macros/
pseudo_class.rs

1/// A macro for defining pseudo classes.
2///
3/// This makes it much easier to define a pseudo class. Parsing is also a little bit delicate, as the two
4/// [Cursors][crate::Cursor] must appear next to each other - no whitespace nor comments can be present betwixt the
5/// colon and ident.
6///
7/// # Example
8///
9/// ```
10/// use css_parse::*;
11/// use csskit_derives::*;
12/// use derive_atom_set::*;
13/// use bumpalo::Bump;
14///
15/// #[derive(Debug, Default, AtomSet, Copy, Clone, PartialEq)]
16/// pub enum MyAtomSet {
17///   #[default]
18///   _None,
19///   Foo,
20///   Bar,
21///   Baz,
22/// }
23/// impl MyAtomSet {
24///   const ATOMS: MyAtomSet = MyAtomSet::_None;
25/// }
26///
27/// pseudo_class!(
28///   /// Some docs on this type...
29///   #[derive(Debug, ToCursors, ToSpan)]
30///   pub enum MyPseudoClass {
31///     Foo: MyAtomSet::Foo,
32///     Bar: MyAtomSet::Bar,
33///     Baz: MyAtomSet::Baz,
34///   }
35/// );
36///
37/// // The result will be one of the variants in the enum, matching the keyword.
38/// assert_parse!(MyAtomSet::ATOMS, MyPseudoClass, ":foo");
39///
40/// // Matches are case insensitive
41/// assert_parse!(MyAtomSet::ATOMS, MyPseudoClass, ":BaR");
42///
43/// // Words that do not match will fail to parse.
44/// assert_parse_error!(MyAtomSet::ATOMS, MyPseudoClass, ":bing");
45///
46/// // The `:` is also required
47/// assert_parse_error!(MyAtomSet::ATOMS, MyPseudoClass, "baz");
48///
49/// // Any tokens between the `:` and ident result in a parse error:
50/// assert_parse_error!(MyAtomSet::ATOMS, MyPseudoClass, ": foo");
51/// ```
52#[macro_export]
53macro_rules! pseudo_class {
54	($(#[$meta:meta])* $vis:vis enum $name: ident { $first_variant: ident: $atoms: ident::$first:ident, $( $variant: ident: $variant_pat: pat$(,)?)* }) => {
55		$(#[$meta])*
56		pub enum $name {
57			$first_variant($crate::T![:], $crate::T![Ident]),
58			$($variant($crate::T![:], $crate::T![Ident]),)*
59		}
60
61		impl<'a> $crate::Peek<'a> for $name {
62			fn peek<I>(p: &$crate::Parser<'a, I>, c: $crate::Cursor) -> bool
63			where
64				I: Iterator<Item = $crate::Cursor> + Clone,
65			{
66				let c2 = p.peek_n(2);
67				c == $crate::Kind::Colon &&
68				c2 == $crate::Kind::Ident &&
69				matches!(p.to_atom::<$atoms>(c2), $atoms::$first $(| $variant_pat)*)
70			}
71		}
72
73		impl<'a> $crate::Parse<'a> for $name {
74			fn parse<I>(p: &mut $crate::Parser<'a, I>) -> $crate::Result<Self>
75			where
76				I: Iterator<Item = $crate::Cursor> + Clone,
77			{
78				let colon = p.parse::<$crate::T![:]>()?;
79				let skip = p.set_skip($crate::KindSet::NONE);
80				let ident = p.parse::<$crate::T![Ident]>();
81				p.set_skip(skip);
82				let ident = ident?;
83				match p.to_atom::<$atoms>(ident.into()) {
84					$atoms::$first => Ok(Self::$first_variant(colon, ident)),
85					$($variant_pat => Ok(Self::$variant(colon, ident)),)*
86					_ => {
87						Err($crate::Diagnostic::new(ident.into(), $crate::Diagnostic::unexpected_ident))?
88					}
89				}
90			}
91		}
92	}
93}
css_parse/macros/pseudo_class.rs

css_parse/macros/
pseudo_class.rs
