Replace TokenSerializationType with TokenSerializationTypeVariants (#369)

* Replace TokenSerializationType with TokenSerializationTypeVariants

Making TokenSerializationType public is useful to describe a CSS string
that is already known to be valid in cases when the
TokenSerializationTypes of the start and end of the CSS string is
needed, but Tokens are not.

This helps with creating a custom_properties::VariableValue from the CSS
string of a computed value for CSS Properties and Values, see Mozilla
bug 1858305 [1].

[1]: https://bugzilla.mozilla.org/show_bug.cgi?id=1858305

* Derive Default trait for TokenSerializationType

* Deprecate TokenSerializationType::nothing()

Author: zrhoffman

src/serializer.rs

@@ -378,19 +378,110 @@ impl_tocss_for_float!(f32);
 impl_tocss_for_float!(f64);
 
 /// A category of token. See the `needs_separator_when_before` method.
-#[derive(Copy, Clone, Eq, PartialEq, Debug)]
-pub struct TokenSerializationType(TokenSerializationTypeVariants);
+#[derive(Copy, Clone, Eq, PartialEq, Debug, Default)]
+pub enum TokenSerializationType {
+    /// No token serialization type.
+    #[default]
+    Nothing,
+
+    /// The [`<whitespace-token>`](https://drafts.csswg.org/css-syntax/#whitespace-token-diagram)
+    /// type.
+    WhiteSpace,
+
+    /// The [`<at-keyword-token>`](https://drafts.csswg.org/css-syntax/#at-keyword-token-diagram)
+    /// type, the "[`<hash-token>`](https://drafts.csswg.org/css-syntax/#hash-token-diagram) with
+    /// the type flag set to 'unrestricted'" type, or the
+    /// "[`<hash-token>`](https://drafts.csswg.org/css-syntax/#hash-token-diagram) with the type
+    /// flag set to 'id'" type.
+    AtKeywordOrHash,
+
+    /// The [`<number-token>`](https://drafts.csswg.org/css-syntax/#number-token-diagram) type.
+    Number,
+
+    /// The [`<dimension-token>`](https://drafts.csswg.org/css-syntax/#dimension-token-diagram)
+    /// type.
+    Dimension,
+
+    /// The [`<percentage-token>`](https://drafts.csswg.org/css-syntax/#percentage-token-diagram)
+    /// type.
+    Percentage,
+
+    /// The [`<url-token>`](https://drafts.csswg.org/css-syntax/#url-token-diagram) or
+    /// `<bad-url-token>` type.
+    UrlOrBadUrl,
+
+    /// The [`<function-token>`](https://drafts.csswg.org/css-syntax/#function-token-diagram) type.
+    Function,
+
+    /// The [`<ident-token>`](https://drafts.csswg.org/css-syntax/#ident-token-diagram) type.
+    Ident,
+
+    /// The `-->` [`<CDC-token>`](https://drafts.csswg.org/css-syntax/#CDC-token-diagram) type.
+    CDC,
+
+    /// The `|=`
+    /// [`<dash-match-token>`](https://drafts.csswg.org/css-syntax/#dash-match-token-diagram) type.
+    DashMatch,
+
+    /// The `*=`
+    /// [`<substring-match-token>`](https://drafts.csswg.org/css-syntax/#substring-match-token-diagram)
+    /// type.
+    SubstringMatch,
+
+    /// The `<(-token>` type.
+    OpenParen,
+
+    /// The `#` `<delim-token>` type.
+    DelimHash,
+
+    /// The `@` `<delim-token>` type.
+    DelimAt,
+
+    /// The `.` or `+` `<delim-token>` type.
+    DelimDotOrPlus,
+
+    /// The `-` `<delim-token>` type.
+    DelimMinus,
+
+    /// The `?` `<delim-token>` type.
+    DelimQuestion,
+
+    /// The `$`, `^`, or `~` `<delim-token>` type.
+    DelimAssorted,
+
+    /// The `=` `<delim-token>` type.
+    DelimEquals,
+
+    /// The `|` `<delim-token>` type.
+    DelimBar,
+
+    /// The `/` `<delim-token>` type.
+    DelimSlash,
+
+    /// The `*` `<delim-token>` type.
+    DelimAsterisk,
+
+    /// The `%` `<delim-token>` type.
+    DelimPercent,
+
+    /// A type indicating any other token.
+    Other,
+}
 
 impl TokenSerializationType {
     /// Return a value that represents the absence of a token, e.g. before the start of the input.
+    #[deprecated(
+        since = "0.32.1",
+        note = "use TokenSerializationType::Nothing or TokenSerializationType::default() instead"
+    )]
     pub fn nothing() -> TokenSerializationType {
-        TokenSerializationType(TokenSerializationTypeVariants::Nothing)
+        Default::default()
     }
 
-    /// If this value is `TokenSerializationType::nothing()`, set it to the given value instead.
+    /// If this value is `TokenSerializationType::Nothing`, set it to the given value instead.
     pub fn set_if_nothing(&mut self, new_value: TokenSerializationType) {
-        if self.0 == TokenSerializationTypeVariants::Nothing {
-            self.0 = new_value.0
+        if matches!(self, TokenSerializationType::Nothing) {
+            *self = new_value
         }
     }
 
@@ -404,10 +495,10 @@ impl TokenSerializationType {
     /// See https://github.com/w3c/csswg-drafts/issues/4088 for the
     /// `DelimPercent` bits.
     pub fn needs_separator_when_before(self, other: TokenSerializationType) -> bool {
-        use self::TokenSerializationTypeVariants::*;
-        match self.0 {
+        use self::TokenSerializationType::*;
+        match self {
             Ident => matches!(
-                other.0,
+                other,
                 Ident
                     | Function
                     | UrlOrBadUrl
@@ -419,15 +510,15 @@ impl TokenSerializationType {
                     | OpenParen
             ),
             AtKeywordOrHash | Dimension => matches!(
-                other.0,
+                other,
                 Ident | Function | UrlOrBadUrl | DelimMinus | Number | Percentage | Dimension | CDC
             ),
             DelimHash | DelimMinus => matches!(
-                other.0,
+                other,
                 Ident | Function | UrlOrBadUrl | DelimMinus | Number | Percentage | Dimension
             ),
             Number => matches!(
-                other.0,
+                other,
                 Ident
                     | Function
                     | UrlOrBadUrl
@@ -437,11 +528,11 @@ impl TokenSerializationType {
                     | DelimPercent
                     | Dimension
             ),
-            DelimAt => matches!(other.0, Ident | Function | UrlOrBadUrl | DelimMinus),
-            DelimDotOrPlus => matches!(other.0, Number | Percentage | Dimension),
-            DelimAssorted | DelimAsterisk => matches!(other.0, DelimEquals),
-            DelimBar => matches!(other.0, DelimEquals | DelimBar | DashMatch),
-            DelimSlash => matches!(other.0, DelimAsterisk | SubstringMatch),
+            DelimAt => matches!(other, Ident | Function | UrlOrBadUrl | DelimMinus),
+            DelimDotOrPlus => matches!(other, Number | Percentage | Dimension),
+            DelimAssorted | DelimAsterisk => matches!(other, DelimEquals),
+            DelimBar => matches!(other, DelimEquals | DelimBar | DashMatch),
+            DelimSlash => matches!(other, DelimAsterisk | SubstringMatch),
             Nothing | WhiteSpace | Percentage | UrlOrBadUrl | Function | CDC | OpenParen
             | DashMatch | SubstringMatch | DelimQuestion | DelimEquals | DelimPercent | Other => {
                 false
@@ -450,43 +541,14 @@ impl TokenSerializationType {
     }
 }
 
-#[derive(Copy, Clone, Eq, PartialEq, Debug)]
-enum TokenSerializationTypeVariants {
-    Nothing,
-    WhiteSpace,
-    AtKeywordOrHash,
-    Number,
-    Dimension,
-    Percentage,
-    UrlOrBadUrl,
-    Function,
-    Ident,
-    CDC,
-    DashMatch,
-    SubstringMatch,
-    OpenParen,      // '('
-    DelimHash,      // '#'
-    DelimAt,        // '@'
-    DelimDotOrPlus, // '.', '+'
-    DelimMinus,     // '-'
-    DelimQuestion,  // '?'
-    DelimAssorted,  // '$', '^', '~'
-    DelimEquals,    // '='
-    DelimBar,       // '|'
-    DelimSlash,     // '/'
-    DelimAsterisk,  // '*'
-    DelimPercent,   // '%'
-    Other,          // anything else
-}
-
 impl<'a> Token<'a> {
     /// Categorize a token into a type that determines when `/**/` needs to be inserted
     /// between two tokens when serialized next to each other without whitespace in between.
     ///
     /// See the `TokenSerializationType::needs_separator_when_before` method.
     pub fn serialization_type(&self) -> TokenSerializationType {
-        use self::TokenSerializationTypeVariants::*;
-        TokenSerializationType(match *self {
+        use self::TokenSerializationType::*;
+        match self {
             Token::Ident(_) => Ident,
             Token::AtKeyword(_) | Token::Hash(_) | Token::IDHash(_) => AtKeywordOrHash,
             Token::UnquotedUrl(_) | Token::BadUrl(_) => UrlOrBadUrl,
@@ -526,6 +588,6 @@ impl<'a> Token<'a> {
             | Token::IncludeMatch
             | Token::PrefixMatch
             | Token::SuffixMatch => Other,
-        })
+        }
     }
 }

src/tests.rs

@@ -466,7 +466,7 @@ fn serializer(preserve_comments: bool) {
             }
             let mut serialized = String::new();
             write_to(
-                TokenSerializationType::nothing(),
+                TokenSerializationType::Nothing,
                 input,
                 &mut serialized,
                 preserve_comments,