Transform all enum-like classes to dart enums (#1777)

* Transform all enum-like classes to dart enums

Fixes #1746

* fix new linter warnings upon upgrading to 2.17 regarding "[new MyClass]" to "[MyClass.new]"

lib/src/ast/sass/expression/binary_operation.dart

@@ -88,51 +88,48 @@ class BinaryOperationExpression implements Expression {
 /// A binary operator constant.
 ///
 /// {@category AST}
-@sealed
-class BinaryOperator {
+enum BinaryOperator {
   /// The Microsoft equals operator, `=`.
-  static const singleEquals = BinaryOperator._("single equals", "=", 0);
+  singleEquals('single equals', '=', 0),
 
   /// The disjunction operator, `or`.
-  static const or = BinaryOperator._("or", "or", 1);
+  or('or', 'or', 1),
 
   /// The conjunction operator, `and`.
-  static const and = BinaryOperator._("and", "and", 2);
+  and('and', 'and', 2),
 
   /// The equality operator, `==`.
-  static const equals = BinaryOperator._("equals", "==", 3);
+  equals('equals', '==', 3),
 
   /// The inequality operator, `!=`.
-  static const notEquals = BinaryOperator._("not equals", "!=", 3);
+  notEquals('not equals', '!=', 3),
 
   /// The greater-than operator, `>`.
-  static const greaterThan = BinaryOperator._("greater than", ">", 4);
+  greaterThan('greater than', '>', 4),
 
   /// The greater-than-or-equal-to operator, `>=`.
-  static const greaterThanOrEquals =
-      BinaryOperator._("greater than or equals", ">=", 4);
+  greaterThanOrEquals('greater than or equals', '>=', 4),
 
   /// The less-than operator, `<`.
-  static const lessThan = BinaryOperator._("less than", "<", 4);
+  lessThan('less than', '<', 4),
 
   /// The less-than-or-equal-to operator, `<=`.
-  static const lessThanOrEquals =
-      BinaryOperator._("less than or equals", "<=", 4);
+  lessThanOrEquals('less than or equals', '<=', 4),
 
   /// The addition operator, `+`.
-  static const plus = BinaryOperator._("plus", "+", 5);
+  plus('plus', '+', 5),
 
   /// The subtraction operator, `-`.
-  static const minus = BinaryOperator._("minus", "-", 5);
+  minus('minus', '-', 5),
 
   /// The multiplication operator, `*`.
-  static const times = BinaryOperator._("times", "*", 6);
+  times('times', '*', 6),
 
   /// The division operator, `/`.
-  static const dividedBy = BinaryOperator._("divided by", "/", 6);
+  dividedBy('divided by', '/', 6),
 
   /// The modulo operator, `%`.
-  static const modulo = BinaryOperator._("modulo", "%", 6);
+  modulo('modulo', '%', 6);
 
   /// The English name of [this].
   final String name;
@@ -145,7 +142,7 @@ class BinaryOperator {
   /// An operator with higher precedence binds tighter.
   final int precedence;
 
-  const BinaryOperator._(this.name, this.operator, this.precedence);
+  const BinaryOperator(this.name, this.operator, this.precedence);
 
   String toString() => name;
 }

lib/src/ast/sass/expression/unary_operation.dart

@@ -38,29 +38,28 @@ class UnaryOperationExpression implements Expression {
 /// A unary operator constant.
 ///
 /// {@category AST}
-@sealed
-class UnaryOperator {
+enum UnaryOperator {
   /// The numeric identity operator, `+`.
-  static const plus = UnaryOperator._("plus", "+");
+  plus('plus', '+'),
 
   /// The numeric negation operator, `-`.
-  static const minus = UnaryOperator._("minus", "-");
+  minus('minus', '-'),
 
   /// The leading slash operator, `/`.
   ///
   /// This is a historical artifact.
-  static const divide = UnaryOperator._("divide", "/");
+  divide('divide', '/'),
 
   /// The boolean negation operator, `not`.
-  static const not = UnaryOperator._("not", "not");
+  not('not', 'not');
 
   /// The English name of [this].
   final String name;
 
   /// The Sass syntax for [this].
   final String operator;
 
-  const UnaryOperator._(this.name, this.operator);
+  const UnaryOperator(this.name, this.operator);
 
   String toString() => name;
 }

lib/src/ast/selector/attribute.dart

@@ -69,31 +69,31 @@ class AttributeSelector extends SimpleSelector {
 }
 
 /// An operator that defines the semantics of an [AttributeSelector].
-class AttributeOperator {
+enum AttributeOperator {
   /// The attribute value exactly equals the given value.
-  static const equal = AttributeOperator._("=");
+  equal('='),
 
   /// The attribute value is a whitespace-separated list of words, one of which
   /// is the given value.
-  static const include = AttributeOperator._("~=");
+  include('~='),
 
   /// The attribute value is either exactly the given value, or starts with the
   /// given value followed by a dash.
-  static const dash = AttributeOperator._("|=");
+  dash('|='),
 
   /// The attribute value begins with the given value.
-  static const prefix = AttributeOperator._("^=");
+  prefix('^='),
 
   /// The attribute value ends with the given value.
-  static const suffix = AttributeOperator._("\$=");
+  suffix('\$='),
 
   /// The attribute value contains the given value.
-  static const substring = AttributeOperator._("*=");
+  substring('*=');
 
   /// The operator's token text.
   final String _text;
 
-  const AttributeOperator._(this._text);
+  const AttributeOperator(this._text);
 
   String toString() => _text;
 }

lib/src/ast/selector/combinator.dart

@@ -2,30 +2,27 @@
 // MIT-style license that can be found in the LICENSE file or at
 // https://opensource.org/licenses/MIT.
 
-import 'package:meta/meta.dart';
-
 /// A combinator that defines the relationship between selectors in a
 /// [ComplexSelector].
 ///
 /// {@category AST}
-@sealed
-class Combinator {
+enum Combinator {
   /// Matches the right-hand selector if it's immediately adjacent to the
   /// left-hand selector in the DOM tree.
-  static const nextSibling = Combinator._("+");
+  nextSibling('+'),
 
   /// Matches the right-hand selector if it's a direct child of the left-hand
   /// selector in the DOM tree.
-  static const child = Combinator._(">");
+  child('>'),
 
   /// Matches the right-hand selector if it comes after the left-hand selector
   /// in the DOM tree.
-  static const followingSibling = Combinator._("~");
+  followingSibling('~');
 
   /// The combinator's token text.
   final String _text;
 
-  const Combinator._(this._text);
+  const Combinator(this._text);
 
   String toString() => _text;
 }

lib/src/callable/async.dart

@@ -36,7 +36,7 @@ abstract class AsyncCallable {
   /// The argument declaration is parsed from [arguments], which should not
   /// include parentheses. Throws a [SassFormatException] if parsing fails.
   ///
-  /// See [new Callable] for more details.
+  /// See [Callable.new] for more details.
   factory AsyncCallable.function(String name, String arguments,
           FutureOr<Value> callback(List<Value> arguments)) =>
       AsyncBuiltInCallable.function(name, arguments, callback);

lib/src/extend/mode.dart

@@ -3,28 +3,28 @@
 // https://opensource.org/licenses/MIT.
 
 /// Different modes in which extension can run.
-class ExtendMode {
+enum ExtendMode {
   /// Normal mode, used with the `@extend` rule.
   ///
   /// This preserves existing selectors and extends each target individually.
-  static const normal = ExtendMode._("normal");
+  normal('normal'),
 
   /// Replace mode, used by the `selector-replace()` function.
   ///
   /// This replaces existing selectors and requires every target to match to
   /// extend a given compound selector.
-  static const replace = ExtendMode._("replace");
+  replace('replace'),
 
   /// All-targets mode, used by the `selector-extend()` function.
   ///
   /// This preserves existing selectors but requires every target to match to
   /// extend a given compound selector.
-  static const allTargets = ExtendMode._("allTargets");
+  allTargets('allTargets');
 
   /// The name of the mode.
   final String name;
 
-  const ExtendMode._(this.name);
+  const ExtendMode(this.name);
 
   String toString() => name;
 }

lib/src/functions/color.dart

@@ -863,7 +863,7 @@ SassColor _transparentize(List<Value> arguments) {
           .clamp(0, 1));
 }
 
-/// Like [new BuiltInCallable.function], but always sets the URL to
+/// Like [BuiltInCallable.function], but always sets the URL to
 /// `sass:color`.
 BuiltInCallable _function(
         String name, String arguments, Value callback(List<Value> arguments)) =>

lib/src/functions/list.dart

@@ -148,7 +148,7 @@ final _slash = _function("slash", r"$elements...", (arguments) {
   return SassList(list, ListSeparator.slash);
 });
 
-/// Like [new BuiltInCallable.function], but always sets the URL to `sass:list`.
+/// Like [BuiltInCallable.function], but always sets the URL to `sass:list`.
 BuiltInCallable _function(
         String name, String arguments, Value callback(List<Value> arguments)) =>
     BuiltInCallable.function(name, arguments, callback, url: "sass:list");

lib/src/functions/map.dart

@@ -218,7 +218,7 @@ SassMap _deepMergeImpl(SassMap map1, SassMap map2) {
   return SassMap(result);
 }
 
-/// Like [new BuiltInCallable.function], but always sets the URL to `sass:map`.
+/// Like [BuiltInCallable.function], but always sets the URL to `sass:map`.
 BuiltInCallable _function(
         String name, String arguments, Value callback(List<Value> arguments)) =>
     BuiltInCallable.function(name, arguments, callback, url: "sass:map");

lib/src/functions/math.dart

@@ -328,7 +328,7 @@ BuiltInCallable _numberFunction(String name, num transform(num value)) {
   });
 }
 
-/// Like [new _function.function], but always sets the URL to `sass:math`.
+/// Like [_function.function], but always sets the URL to `sass:math`.
 BuiltInCallable _function(
         String name, String arguments, Value callback(List<Value> arguments)) =>
     BuiltInCallable.function(name, arguments, callback, url: "sass:math");

lib/src/functions/meta.dart

@@ -79,7 +79,7 @@ final local = UnmodifiableListView([
   })
 ]);
 
-/// Like [new BuiltInCallable.function], but always sets the URL to `sass:meta`.
+/// Like [BuiltInCallable.function], but always sets the URL to `sass:meta`.
 BuiltInCallable _function(
         String name, String arguments, Value callback(List<Value> arguments)) =>
     BuiltInCallable.function(name, arguments, callback, url: "sass:meta");

lib/src/functions/selector.dart

@@ -162,7 +162,7 @@ CompoundSelector? _prependParent(CompoundSelector compound) {
   }
 }
 
-/// Like [new BuiltInCallable.function], but always sets the URL to
+/// Like [BuiltInCallable.function], but always sets the URL to
 /// `sass:selector`.
 BuiltInCallable _function(
         String name, String arguments, Value callback(List<Value> arguments)) =>

lib/src/functions/string.dart

@@ -168,7 +168,7 @@ int _codepointForIndex(int index, int lengthInCodepoints,
   return result;
 }
 
-/// Like [new BuiltInCallable.function], but always sets the URL to
+/// Like [BuiltInCallable.function], but always sets the URL to
 /// `sass:string`.
 BuiltInCallable _function(
         String name, String arguments, Value callback(List<Value> arguments)) =>

lib/src/syntax.dart

@@ -2,22 +2,20 @@
 // MIT-style license that can be found in the LICENSE file or at
 // https://opensource.org/licenses/MIT.
 
-import 'package:meta/meta.dart';
 import 'package:path/path.dart' as p;
 
 /// An enum of syntaxes that Sass can parse.
 ///
 /// {@category Compile}
-@sealed
-class Syntax {
+enum Syntax {
   /// The CSS-superset SCSS syntax.
-  static const scss = Syntax._("SCSS");
+  scss('SCSS'),
 
   /// The whitespace-sensitive indented syntax.
-  static const sass = Syntax._("Sass");
+  sass('Sass'),
 
   /// The plain CSS syntax, which disallows special Sass features.
-  static const css = Syntax._("CSS");
+  css('CSS');
 
   /// Returns the default syntax to use for a file loaded from [path].
   static Syntax forPath(String path) {
@@ -34,7 +32,7 @@ class Syntax {
   /// The name of the syntax.
   final String _name;
 
-  const Syntax._(this._name);
+  const Syntax(this._name);
 
   String toString() => _name;
 }

lib/src/value.dart

@@ -32,7 +32,7 @@ export 'value/string.dart';
 /// A SassScript value.
 ///
 /// All SassScript values are unmodifiable. New values can be constructed using
-/// subclass constructors like [new SassString]. Untyped values can be cast to
+/// subclass constructors like [SassString.new]. Untyped values can be cast to
 /// particular types using `assert*()` functions like [assertString], which
 /// throw user-friendly error messages if they fail.
 ///

lib/src/value/calculation.dart

@@ -365,19 +365,18 @@ class CalculationOperation {
 /// An enumeration of possible operators for [CalculationOperation].
 ///
 /// {@category Value}
-@sealed
-class CalculationOperator {
+enum CalculationOperator {
   /// The addition operator.
-  static const plus = CalculationOperator._("plus", "+", 1);
+  plus('plus', '+', 1),
 
   /// The subtraction operator.
-  static const minus = CalculationOperator._("minus", "-", 1);
+  minus('minus', '-', 1),
 
   /// The multiplication operator.
-  static const times = CalculationOperator._("times", "*", 2);
+  times('times', '*', 2),
 
   /// The division operator.
-  static const dividedBy = CalculationOperator._("divided by", "/", 2);
+  dividedBy('divided by', '/', 2);
 
   /// The English name of [this].
   final String name;
@@ -393,7 +392,7 @@ class CalculationOperator {
   @internal
   final int precedence;
 
-  const CalculationOperator._(this.name, this.operator, this.precedence);
+  const CalculationOperator(this.name, this.operator, this.precedence);
 
   String toString() => name;
 }