less · matthew-dean · Aug 5, 2023 · Jul 20, 2023 · Aug 2, 2023 · Aug 3, 2023
diff --git a/dist/less.js b/dist/less.js
diff --git a/dist/less.min.js b/dist/less.min.js
diff --git a/dist/less.min.js.map b/dist/less.min.js.map
diff --git a/packages/less/dist/less.js b/packages/less/dist/less.js
diff --git a/packages/less/dist/less.min.js b/packages/less/dist/less.min.js
diff --git a/packages/less/dist/less.min.js.map b/packages/less/dist/less.min.js.map
diff --git a/packages/less/src/less/parser/parser-input.js b/packages/less/src/less/parser/parser-input.js
@@ -149,6 +149,13 @@ export default () => {
         return tok;
     };
 
+    parserInput.$peekChar = tok => {
+        if (input.charAt(parserInput.i) !== tok) {
+            return null;
+        }
+        return tok;
+    };
+
     parserInput.$str = tok => {
         const tokLength = tok.length;
 

diff --git a/packages/less/src/less/parser/parser.js b/packages/less/src/less/parser/parser.js
@@ -4,6 +4,7 @@ import visitors from '../visitors';
 import getParserInput from './parser-input';
 import * as utils from '../utils';
 import functionRegistry from '../functions/function-registry';
+import { ContainerSyntaxOptions, MediaSyntaxOptions } from '../tree/atrule-syntax';
 
 //
 // less.js - parser
@@ -1698,7 +1699,7 @@ const Parser = function Parser(context, imports, fileInfo, currentIndex) {
                     const options = (dir ? this.importOptions() : null) || {};
 
                     if ((path = this.entities.quoted() || this.entities.url())) {
-                        features = this.mediaFeatures();
+                        features = this.mediaFeatures({});
 
                         if (!parserInput.$char(';')) {
                             parserInput.i = index;
@@ -1752,7 +1753,7 @@ const Parser = function Parser(context, imports, fileInfo, currentIndex) {
                 }
             },
 
-            mediaFeature: function () {
+            mediaFeature: function (syntaxOptions) {
                 const entities = this.entities;
                 const nodes = [];
                 let e;
@@ -1764,10 +1765,20 @@ const Parser = function Parser(context, imports, fileInfo, currentIndex) {
                         nodes.push(e);
                     } else if (parserInput.$char('(')) {
                         p = this.property();
-                        e = this.value();
+                        parserInput.save();
+                        if (!p && syntaxOptions.queryInParens && parserInput.$re(/^[a-z-]*\s*([<>]=|<=|>=|[<>]|=)/)) {
+                            parserInput.restore();
+                            p = this.condition();
+                        } else {
+                            parserInput.restore();
+                            e = this.value();
+                        }
                         if (parserInput.$char(')')) {
-                            if (p && e) {
-                                nodes.push(new(tree.Paren)(new(tree.Declaration)(p, e, null, null, parserInput.i + currentIndex, fileInfo, true)));
+                            if (p && !e) {
+                                nodes.push(new (tree.Paren)(new (tree.QueryInParens)(p.op, p.lvalue, p.rvalue, p._index)));
+                                e = p;
+                            } else if (p && e) {
+                                nodes.push(new (tree.Paren)(new (tree.Declaration)(p, e, null, null, parserInput.i + currentIndex, fileInfo, true)));
                             } else if (e) {
                                 nodes.push(new(tree.Paren)(e));
                             } else {
@@ -1785,12 +1796,12 @@ const Parser = function Parser(context, imports, fileInfo, currentIndex) {
                 }
             },
 
-            mediaFeatures: function () {
+            mediaFeatures: function (syntaxOptions) {
                 const entities = this.entities;
                 const features = [];
                 let e;
                 do {
-                    e = this.mediaFeature();
+                    e = this.mediaFeature(syntaxOptions);
                     if (e) {
                         features.push(e);
                         if (!parserInput.$char(',')) { break; }
@@ -1806,38 +1817,44 @@ const Parser = function Parser(context, imports, fileInfo, currentIndex) {
                 return features.length > 0 ? features : null;
             },
 
-            media: function () {
-                let features;
-                let rules;
-                let media;
+            prepareAndGetNestableAtRule: function (treeType, index, debugInfo, syntaxOptions) {
+                const features = this.mediaFeatures(syntaxOptions);
+
+                const rules = this.block();
+
+                if (!rules) {
+                    error('media definitions require block statements after any features');
+                }
+
+                parserInput.forget();
+
+                const atRule = new (treeType)(rules, features, index + currentIndex, fileInfo);
+                if (context.dumpLineNumbers) {
+                    atRule.debugInfo = debugInfo;
+                }
+
+                return atRule;
+            },
+
+            nestableAtRule: function () {
                 let debugInfo;
                 const index = parserInput.i;
 
                 if (context.dumpLineNumbers) {
                     debugInfo = getDebugInfo(index);
                 }
-
                 parserInput.save();
 
-                if (parserInput.$str('@media')) {
-                    features = this.mediaFeatures();
-
-                    rules = this.block();
-
-                    if (!rules) {
-                        error('media definitions require block statements after any features');
+                if (parserInput.$peekChar('@')) {
+                    if (parserInput.$str('@media')) {
+                        return this.prepareAndGetNestableAtRule(tree.Media, index, debugInfo, MediaSyntaxOptions);
                     }
-
-                    parserInput.forget();
-
-                    media = new(tree.Media)(rules, features, index + currentIndex, fileInfo);
-                    if (context.dumpLineNumbers) {
-                        media.debugInfo = debugInfo;
+
+                    if (parserInput.$str('@container')) {
+                        return this.prepareAndGetNestableAtRule(tree.Container, index, debugInfo, ContainerSyntaxOptions);
                     }
-
-                    return media;
                 }
-
+                
                 parserInput.restore();
             },
 
@@ -1919,7 +1936,7 @@ const Parser = function Parser(context, imports, fileInfo, currentIndex) {
 
                 if (parserInput.currentChar() !== '@') { return; }
 
-                value = this['import']() || this.plugin() || this.media();
+                value = this['import']() || this.plugin() || this.nestableAtRule();
                 if (value) {
                     return value;
                 }
@@ -2422,4 +2439,4 @@ Parser.serializeVars = vars => {
     return s;
 };
 
-export default Parser;
+export default Parser;
diff --git a/packages/less/src/less/tree/atrule-syntax.js b/packages/less/src/less/tree/atrule-syntax.js
@@ -0,0 +1,7 @@
+export const MediaSyntaxOptions = {
+    queryInParens: false
+};
+
+export const ContainerSyntaxOptions = {
+    queryInParens: true
+};
diff --git a/packages/less/src/less/tree/container.js b/packages/less/src/less/tree/container.js
@@ -0,0 +1,63 @@
+import Ruleset from './ruleset';
+import Value from './value';
+import Selector from './selector';
+import AtRule from './atrule';
+import NestableAtRulePrototype from './nested-at-rule';
+
+const Container = function(value, features, index, currentFileInfo, visibilityInfo) {
+    this._index = index;
+    this._fileInfo = currentFileInfo;
+
+    const selectors = (new Selector([], null, null, this._index, this._fileInfo)).createEmptySelectors();
+
+    this.features = new Value(features);
+    this.rules = [new Ruleset(selectors, value)];
+    this.rules[0].allowImports = true;
+    this.copyVisibilityInfo(visibilityInfo);
+    this.allowRoot = true;
+    this.setParent(selectors, this);
+    this.setParent(this.features, this);
+    this.setParent(this.rules, this);
+};
+
+Container.prototype = Object.assign(new AtRule(), {
+    type: 'Container',
+
+    ...NestableAtRulePrototype,
+
+    genCSS(context, output) {
+        output.add('@container ', this._fileInfo, this._index);
+        this.features.genCSS(context, output);
+        this.outputRuleset(context, output, this.rules);
+    },
+
+    eval(context) {
+        if (!context.mediaBlocks) {
+            context.mediaBlocks = [];
+            context.mediaPath = [];
+        }
+
+        const media = new Container(null, [], this._index, this._fileInfo, this.visibilityInfo());
+        if (this.debugInfo) {
+            this.rules[0].debugInfo = this.debugInfo;
+            media.debugInfo = this.debugInfo;
+        }
+
+        media.features = this.features.eval(context);
+
+        context.mediaPath.push(media);
+        context.mediaBlocks.push(media);
+
+        this.rules[0].functionRegistry = context.frames[0].functionRegistry.inherit();
+        context.frames.unshift(this.rules[0]);
+        media.rules = [this.rules[0].eval(context)];
+        context.frames.shift();
+
+        context.mediaPath.pop();
+
+        return context.mediaPath.length === 0 ? media.evalTop(context) :
+            media.evalNested(context);
+    }
+});
+
+export default Container;
diff --git a/packages/less/src/less/tree/index.js b/packages/less/src/less/tree/index.js
@@ -25,8 +25,10 @@ import Value from './value';
 import JavaScript from './javascript';
 import Assignment from './assignment';
 import Condition from './condition';
+import QueryInParens from './query-in-parens';
 import Paren from './paren';
 import Media from './media';
+import Container from './container';
 import UnicodeDescriptor from './unicode-descriptor';
 import Negative from './negative';
 import Extend from './extend';
@@ -43,8 +45,9 @@ export default {
     Ruleset, Element, Attribute, Combinator, Selector,
     Quoted, Expression, Declaration, Call, URL, Import,
     Comment, Anonymous, Value, JavaScript, Assignment,
-    Condition, Paren, Media, UnicodeDescriptor, Negative,
-    Extend, VariableCall, NamespaceValue,
+    Condition, Paren, Media, Container, QueryInParens, 
+    UnicodeDescriptor, Negative, Extend, VariableCall, 
+    NamespaceValue,
     mixin: {
         Call: MixinCall,
         Definition: MixinDefinition

diff --git a/packages/less/src/less/tree/media.js b/packages/less/src/less/tree/media.js
@@ -1,10 +1,8 @@
 import Ruleset from './ruleset';
 import Value from './value';
 import Selector from './selector';
-import Anonymous from './anonymous';
-import Expression from './expression';
 import AtRule from './atrule';
-import * as utils from '../utils';
+import NestableAtRulePrototype from './nested-at-rule';
 
 const Media = function(value, features, index, currentFileInfo, visibilityInfo) {
     this._index = index;
@@ -25,18 +23,7 @@ const Media = function(value, features, index, currentFileInfo, visibilityInfo)
 Media.prototype = Object.assign(new AtRule(), {
     type: 'Media',
 
-    isRulesetLike() {
-        return true;
-    },
-
-    accept(visitor) {
-        if (this.features) {
-            this.features = visitor.visit(this.features);
-        }
-        if (this.rules) {
-            this.rules = visitor.visitArray(this.rules);
-        }
-    },
+    ...NestableAtRulePrototype,
 
     genCSS(context, output) {
         output.add('@media ', this._fileInfo, this._index);
@@ -70,83 +57,6 @@ Media.prototype = Object.assign(new AtRule(), {
 
         return context.mediaPath.length === 0 ? media.evalTop(context) :
             media.evalNested(context);
-    },
-
-    evalTop(context) {
-        let result = this;
-
-        // Render all dependent Media blocks.
-        if (context.mediaBlocks.length > 1) {
-            const selectors = (new Selector([], null, null, this.getIndex(), this.fileInfo())).createEmptySelectors();
-            result = new Ruleset(selectors, context.mediaBlocks);
-            result.multiMedia = true;
-            result.copyVisibilityInfo(this.visibilityInfo());
-            this.setParent(result, this);
-        }
-
-        delete context.mediaBlocks;
-        delete context.mediaPath;
-
-        return result;
-    },
-
-    evalNested(context) {
-        let i;
-        let value;
-        const path = context.mediaPath.concat([this]);
-
-        // Extract the media-query conditions separated with `,` (OR).
-        for (i = 0; i < path.length; i++) {
-            value = path[i].features instanceof Value ?
-                path[i].features.value : path[i].features;
-            path[i] = Array.isArray(value) ? value : [value];
-        }
-
-        // Trace all permutations to generate the resulting media-query.
-        //
-        // (a, b and c) with nested (d, e) ->
-        //    a and d
-        //    a and e
-        //    b and c and d
-        //    b and c and e
-        this.features = new Value(this.permute(path).map(path => {
-            path = path.map(fragment => fragment.toCSS ? fragment : new Anonymous(fragment));
-
-            for (i = path.length - 1; i > 0; i--) {
-                path.splice(i, 0, new Anonymous('and'));
-            }
-
-            return new Expression(path);
-        }));
-        this.setParent(this.features, this);
-
-        // Fake a tree-node that doesn't output anything.
-        return new Ruleset([], []);
-    },
-
-    permute(arr) {
-        if (arr.length === 0) {
-            return [];
-        } else if (arr.length === 1) {
-            return arr[0];
-        } else {
-            const result = [];
-            const rest = this.permute(arr.slice(1));
-            for (let i = 0; i < rest.length; i++) {
-                for (let j = 0; j < arr[0].length; j++) {
-                    result.push([arr[0][j]].concat(rest[i]));
-                }
-            }
-            return result;
-        }
-    },
-
-    bubbleSelectors(selectors) {
-        if (!selectors) {
-            return;
-        }
-        this.rules = [new Ruleset(utils.copyArray(selectors), [this.rules[0]])];
-        this.setParent(this.rules, this);
     }
 });