[Attr Type] Flush to spec (#4045)

Author: nex3

accepted/attr-type.changes.md

@@ -1,3 +1,12 @@
+## Draft 2.0
+
+* Match the name `type` case-insensitively when checking for invalid functions.
+
+* Don't allow indent tokens after `%` even if it would complete a statement.
+
+* Consider `attr()` calls to be special numbers now that they can be return
+  numbers in CSS and not just strings.
+
 ## Draft 1.1
 
 * Add `type` to the list of forbidden function names.

accepted/attr-type.md

@@ -1,4 +1,4 @@
-# Attr Type: Draft 1.1
+# Attr Type: Draft 2.0
 
 *([Issue](https://github.com/sass/sass/issues/4030),
 [Changelog](attr-type.changes.md))*
@@ -7,6 +7,8 @@
 
 * [Background](#background)
 * [Summary](#summary)
+* [Definitions](#definitions)
+  * [Special Number](#special-number)
 * [Syntax](#syntax)
   * [`SpecialFunctionExpression`](#specialfunctionexpression)
   * [`SingleExpression`](#singleexpression)
@@ -62,6 +64,15 @@ anticipate that a single `%` will be widely used in other contexts, so we don't
 plan to deprecate the modulo operator, although that path is open in the future
 if CSS starts using this value more widely.
 
+## Definitions
+
+### Special Number
+
+Add `attr(` to the list of unquoted string prefixes that qualify as [special
+numbers].
+
+[special numbers]: ../spec/functions.md#special-number
+
 ## Syntax
 
 ### `SpecialFunctionExpression`
@@ -82,15 +93,28 @@ Change [the `SpecialFunctionName` production] to be:
 
 ### `SingleExpression`
 
-Add `Percent` as a production to [`SingleExpression`] with the annotation "If
-this is ambiguous with part of `ProductExpression`, parse `ProductExpression`
-preferentially".
+Add `Percent` as a production to [`SingleExpression`] with the following
+annotation:
 
 [`SingleExpression`]: ../spec/syntax.md#singleexpression
 
+If this is ambiguous with part of `ProductExpression`, parse `ProductExpression`
+preferentially. If this is followed by a [`Whitespace`] that contains a
+[`LineBreak`], do not parse that `Whitespace` as part of an [`IndentSame`] or
+[`IndentMore`] production.
+
+[`Whitespace`]: ../spec/statement.md#whitespace
+[`LineBreak`]: ../spec/statement.md#whitespace
+[`IndentSame`]: ../spec/statement.md#indentation
+[`IndentMore`]: ../spec/statement.md#indentation
+
 > This effectively means that the unquoted string `%` is allowed everywhere
 > *except* in a middle element of a space-separated list, since that would be
-> ambiguous with a modulo operation.
+> ambiguous with a modulo operation. The whitespace clause ensures that a `%` at
+> the end of a line in the indented syntax always looks at the next token, for
+> backwards-compatibility with parsing it as an operator and so that whether the
+> statement ends on that line or not doesn't depend on the first token of the
+> next line.
 
 ### `Percent`
 
@@ -110,7 +134,7 @@ In the [semantics for `@function`], add a bullet point below the second:
 
 [semantics for `@function`]: ../spec/at-rules/function.md#semantics
 
-* If `name` is `type`, throw an error.
+* If `name` is case-insensitively equal to `type`, throw an error.
 
 > Unlike other forbidden function names, this doesn't cover vendor prefixes.
 > This is for two reasons: first, we don't expect to add special parsing for

js-api-doc/deprecations.d.ts

@@ -6,7 +6,7 @@
  */
 export interface Deprecations {
   // START AUTOGENERATED LIST
-  // Checksum: 47c97f7824eb25d7f1e64e3230938b88330d40b4
+  // Checksum: 3639e60773866019c018ae16267c8f23e4df86cf
 
   /**
    * Deprecation for passing a string directly to meta.call().
@@ -162,6 +162,13 @@ export interface Deprecations {
    */
   'global-builtin': Deprecation<'global-builtin'>;
 
+  /**
+   * Deprecation for functions named "type".
+   *
+   * This deprecation became active in Dart Sass 1.86.0.
+   */
+  'type-function': Deprecation<'type-function'>;
+
   // END AUTOGENERATED LIST
 
   /**

spec/at-rules/function.md

@@ -23,6 +23,14 @@ To execute a `@function` rule `rule`:
 
 * Let `name` be the value of `rule`'s `Identifier`.
 
+* If `name` is case-insensitively equal to `type`, throw an error.
+
+  > Unlike other forbidden function names, this doesn't cover vendor prefixes.
+  > This is for two reasons: first, we don't expect to add special parsing for
+  > `type()` with vendor prefixes. Second, "type" is a relatively common word,
+  > so it's likely for private function names to end with `-type` in a way that
+  > could be indistinguishable from a vendor prefix.
+
 * If `name` begins with `--`, throw an error.
 
 * If `name` is `calc`, `element`, `expression`, `url`, `and`, `or`, or `not`, or

spec/deprecations.yaml

@@ -147,3 +147,9 @@ global-builtin:
   dart-sass:
     status: active
     deprecated: 1.80.0
+
+type-function:
+  description: 'Functions named "type".'
+  dart-sass:
+    status: active
+    deprecated: 1.86.0

spec/functions.md

@@ -31,8 +31,8 @@ A *special number* is either:
 * a [calculation], or
 * an unquoted string that CSS will recognize as a function that may return a
   number. For the purposes of Sass, this is any unquoted string that begins with
-  `calc(`, `var(`, `env(`, `clamp(`, `min(`, or `max(`. This matching is
-  case-insensitive.
+  `calc(`, `var(`, `env(`, `attr(`, `clamp(`, `min(`, or `max(`. This matching
+  is case-insensitive.
 
 [calculation]: types/calculation.md
 

spec/js-api/deprecations.d.ts.md

@@ -29,7 +29,7 @@
 ### `Deprecations`
 
 <!-- START AUTOGENERATED LIST -->
-<!-- Checksum: 47c97f7824eb25d7f1e64e3230938b88330d40b4 -->
+<!-- Checksum: 3639e60773866019c018ae16267c8f23e4df86cf -->
 ```ts
 export interface Deprecations {
   'call-string': Deprecation<'call-string'>;
@@ -54,6 +54,7 @@ export interface Deprecations {
   'legacy-js-api': Deprecation<'legacy-js-api'>;
   import: Deprecation<'import'>;
   'global-builtin': Deprecation<'global-builtin'>;
+  'type-function': Deprecation<'type-function'>;
   'user-authored': Deprecation<'user-authored', 'user'>;
 }
 ```

spec/syntax.md

@@ -23,6 +23,8 @@
   * [Consuming a Name](#consuming-a-name)
   * [Consuming an Escaped Code Point](#consuming-an-escaped-code-point)
   * [Consuming a special function](#consuming-a-special-function)
+* [Semantics](#semantics)
+  * [`Percent`](#percent)
 
 ## Definitions
 
@@ -173,6 +175,8 @@ parentheses.
                    | UnaryExpression
                    | UnicodeRange
                    | [Variable]
+                   | Percent³
+**Percent**          ::= '%'
 </pre></x>
 
 [BracketedListExpression]: types/list.md#syntax
@@ -185,6 +189,24 @@ parentheses.
 2: If this is ambiguous with any other production, parse the other production
    preferentially.
 
+3: If this is ambiguous with part of `ProductExpression`, parse
+   `ProductExpression` preferentially. If this is followed by a [`Whitespace`]
+   that contains a [`LineBreak`], do not parse that `Whitespace` as part of an
+   [`IndentSame`] or [`IndentMore`] production.
+
+   > This effectively means that the unquoted string `%` is allowed everywhere
+   > *except* in a middle element of a space-separated list, since that would be
+   > ambiguous with a modulo operation. The whitespace clause ensures that a `%`
+   > at the end of a line in the indented syntax always looks at the next token,
+   > for backwards-compatibility with parsing it as an operator and so that
+   > whether the statement ends on that line or not doesn't depend on the first
+   > token of the next line.
+
+[`Whitespace`]: statement.md#whitespace
+[`LineBreak`]: statement.md#whitespace
+[`IndentSame`]: statement.md#indentation
+[`IndentMore`]: statement.md#indentation
+
 ### `SpecialFunctionExpression`
 
 > These functions are "special" in the sense that their arguments don't use the
@@ -195,9 +217,14 @@ parentheses.
 **SpecialFunctionExpression** ::= SpecialFunctionName InterpolatedDeclarationValue ')'
 **SpecialFunctionName**¹      ::= VendorPrefix? ('element(' | 'expression(')
 &#32;                           | VendorPrefix 'calc('
+&#32;                           | 'type('
 **VendorPrefix**¹             ::= '-' ([identifier-start code point] | [digit]) '-'
 </pre></x>
 
+> No browser has yet supported `type()` with a vendor prefix, nor are they
+> likely to do so in the future given that vendor prefixes are largely unpopular
+> now.
+
 [digit]: https://drafts.csswg.org/css-syntax-3/#digit
 
 1: Both `SpecialFunctionName` and `VendorPrefix` are matched case-insensitively,
@@ -477,3 +504,9 @@ SassScript expression.
 * Return an unquoted interpolated string expression that would be identical to
   the source text according to CSS semantics for all possible interpolated
   strings.
+  
+## Semantics
+
+### `Percent`
+
+To evaluate a `Percent`, return an unquoted string with the value `%`.