detached rulesets

build/build.yml

@@ -127,6 +127,7 @@ tree:
   - <%= build.lib %>/tree/color.js
   - <%= build.lib %>/tree/comment.js
   - <%= build.lib %>/tree/condition.js
+  - <%= build.lib %>/tree/detached-ruleset.js
   - <%= build.lib %>/tree/dimension.js
   - <%= build.lib %>/tree/directive.js
   - <%= build.lib %>/tree/element.js
@@ -143,6 +144,7 @@ tree:
   - <%= build.lib %>/tree/quoted.js
   - <%= build.lib %>/tree/rule.js
   - <%= build.lib %>/tree/ruleset.js
+  - <%= build.lib %>/tree/ruleset-call.js
   - <%= build.lib %>/tree/selector.js
   - <%= build.lib %>/tree/unicode-descriptor.js
   - <%= build.lib %>/tree/url.js

lib/less/index.js

@@ -94,6 +94,7 @@ var less = {
 
 require('./tree/color');
 require('./tree/directive');
+require('./tree/detached-ruleset');
 require('./tree/operation');
 require('./tree/dimension');
 require('./tree/keyword');
@@ -120,6 +121,7 @@ require('./tree/media');
 require('./tree/unicode-descriptor');
 require('./tree/negative');
 require('./tree/extend');
+require('./tree/ruleset-call');
 
 
 var isUrlRe = /^(?:https?:)?\/\//i;

lib/less/parser.js

@@ -43,8 +43,7 @@ less.Parser = function Parser(env) {
     var input,       // LeSS input string
         i,           // current index in `input`
         j,           // current chunk
-        temp,        // temporarily holds a chunk's state, for backtracking
-        memo,        // temporarily holds `i`, when backtracking
+        saveStack = [],   // holds state for backtracking
         furthest,    // furthest index the parser has gone to
         chunks,      // chunkified input
         current,     // current chunk
@@ -111,8 +110,9 @@ less.Parser = function Parser(env) {
         }
     };
 
-    function save()    { temp = current; memo = currentPos = i; }
-    function restore() { current = temp; currentPos = i = memo; }
+    function save()    { currentPos = i; saveStack.push( { current: current, i: i, j: j }); }
+    function restore() { var state = saveStack.pop(); current = state.current; currentPos = i = state.i; j = state.j; }
+    function forget() { saveStack.pop(); }
 
     function sync() {
         if (i > currentPos) {
@@ -424,7 +424,7 @@ less.Parser = function Parser(env) {
                             if (--level < 0) {
                                 return fail("missing opening `{`");
                             }
-                            if (!level) { emitChunk(); }
+                            if (!level && !parenLevel) { emitChunk(); }
                             continue;
                         case 92:                        // \
                             if (parserCurrentIndex < len - 1) { parserCurrentIndex++; continue; }
@@ -729,14 +729,17 @@ less.Parser = function Parser(env) {
                 while (current)
                 {
                     node = this.extendRule() || mixin.definition() || this.rule() || this.ruleset() ||
-                        mixin.call() || this.comment() || this.directive();
+                        mixin.call() || this.comment() || this.rulesetCall() || this.directive();
                     if (node) {
                         root.push(node);
                     } else {
                         if (!($re(/^[\s\n]+/) || $re(/^;+/))) {
                             break;
                         }
                     }
+                    if (peekChar('}')) {
+                        break;
+                    }
                 }
 
                 return root;
@@ -1027,6 +1030,19 @@ less.Parser = function Parser(env) {
                 if (input.charAt(i) === '@' && (name = $re(/^(@[\w-]+)\s*:/))) { return name[1]; }
             },
 
+            //
+            // The variable part of a variable definition. Used in the `rule` parser
+            //
+            //     @fink();
+            //
+            rulesetCall: function () {
+                var name;
+
+                if (input.charAt(i) === '@' && (name = $re(/^(@[\w-]+)\s*\(\s*\)\s*;/))) { 
+                    return new tree.RulesetCall(name[1]); 
+                }
+            },
+
             //
             // extend syntax - used to extend selectors
             //
@@ -1112,6 +1128,7 @@ less.Parser = function Parser(env) {
                         }
 
                         if (parsers.end()) {
+                            forget();
                             return new(tree.mixin.Call)(elements, args, index, env.currentFileInfo, important);
                         }
                     }
@@ -1124,9 +1141,11 @@ less.Parser = function Parser(env) {
                         expressions = [], argsSemiColon = [], argsComma = [],
                         isSemiColonSeperated, expressionContainsNamed, name, nameLoop, value, arg;
 
+                    save();
+
                     while (true) {
                         if (isCall) {
-                            arg = parsers.expression();
+                            arg = parsers.detachedRuleset() || parsers.expression();
                         } else {
                             parsers.comments();
                             if (input.charAt(i) === '.' && $re(/^\.{3}/)) {
@@ -1154,7 +1173,7 @@ less.Parser = function Parser(env) {
 
                         if (isCall) {
                             // Variable
-                            if (arg.value.length == 1) {
+                            if (arg.value && arg.value.length == 1) {
                                 val = arg.value[0];
                             }
                         } else {
@@ -1169,7 +1188,21 @@ less.Parser = function Parser(env) {
                                     }
                                     expressionContainsNamed = true;
                                 }
-                                value = expect(parsers.expression);
+
+                                // we do not support setting a ruleset as a default variable - it doesn't make sense
+                                // However if we do want to add it, there is nothing blocking it, just don't error
+                                // and remove isCall dependency below
+                                value = (isCall && parsers.detachedRuleset()) || parsers.expression();
+
+                                if (!value) {
+                                    if (isCall) {
+                                        error("could not understand value for named argument");
+                                    } else {
+                                        restore();
+                                        returner.args = [];
+                                        return returner;
+                                    }
+                                }
                                 nameLoop = (name = val.name);
                             } else if (!isCall && $re(/^\.{3}/)) {
                                 returner.variadic = true;
@@ -1214,6 +1247,7 @@ less.Parser = function Parser(env) {
                         }
                     }
 
+                    forget();
                     returner.args = isSemiColonSeperated ? argsSemiColon : argsComma;
                     return returner;
                 },
@@ -1254,10 +1288,14 @@ less.Parser = function Parser(env) {
                         variadic = argInfo.variadic;
 
                         // .mixincall("@{a}");
-                        // looks a bit like a mixin definition.. so we have to be nice and restore
+                        // looks a bit like a mixin definition.. 
+                        // also
+                        // .mixincall(@a: {rule: set;});
+                        // so we have to be nice and restore
                         if (!$char(')')) {
                             furthest = i;
                             restore();
+                            return;
                         }
 
                         parsers.comments();
@@ -1269,10 +1307,13 @@ less.Parser = function Parser(env) {
                         ruleset = parsers.block();
 
                         if (ruleset) {
+                            forget();
                             return new(tree.mixin.Definition)(name, params, ruleset, cond, variadic);
                         } else {
                             restore();
                         }
+                    } else {
+                        forget();
                     }
                 }
             },
@@ -1336,10 +1377,16 @@ less.Parser = function Parser(env) {
                     this.entities.variableCurly();
 
                 if (! e) {
+                    save();
                     if ($char('(')) {
                         if ((v = this.selector()) && $char(')')) {
                             e = new(tree.Paren)(v);
+                            forget();
+                        } else {
+                            restore();
                         }
+                    } else {
+                        forget();
                     }
                 }
 
@@ -1442,6 +1489,22 @@ less.Parser = function Parser(env) {
                 }
             },
 
+            blockRuleset: function() {
+                var block = this.block();
+
+                if (block) {
+                    block = new tree.Ruleset(null, block);
+                }
+                return block;
+            },
+
+            detachedRuleset: function() {
+                var blockRuleset = this.blockRuleset();
+                if (blockRuleset) {
+                    return new tree.DetachedRuleset(blockRuleset);
+                }
+            },
+
             //
             // div, .class, body > p {...}
             //
@@ -1472,6 +1535,7 @@ less.Parser = function Parser(env) {
                 }
 
                 if (selectors && (rules = this.block())) {
+                    forget();
                     var ruleset = new(tree.Ruleset)(selectors, rules, env.strictImports);
                     if (env.dumpLineNumbers) {
                         ruleset.debugInfo = debugInfo;
@@ -1484,35 +1548,47 @@ less.Parser = function Parser(env) {
                 }
             },
             rule: function (tryAnonymous) {
-                var name, value, c = input.charAt(i), important, merge;
-                save();
+                var name, value, startOfRule = i, c = input.charAt(startOfRule), important, merge, isVariable;
 
                 if (c === '.' || c === '#' || c === '&') { return; }
 
+                save();
+
                 name = this.variable() || this.ruleProperty();
                 if (name) {
-                    // prefer to try to parse first if its a variable or we are compressing
-                    // but always fallback on the other one
-                    value = !tryAnonymous && (env.compress || (name.charAt && (name.charAt(0) === '@'))) ?
-                        (this.value() || this.anonymousValue()) :
-                        (this.anonymousValue() || this.value());
-
-                    important = this.important();
+                    isVariable = typeof name === "string";
 
-                    // a name returned by this.ruleProperty() is always an array of the form:
-                    // [string-1, ..., string-n, ""] or [string-1, ..., string-n, "+"]
-                    // where each item is a tree.Keyword or tree.Variable
-                    merge = name.pop && name.pop().value;
+                    if (isVariable) {
+                        value = this.detachedRuleset();
+                    }
+
+                    if (!value) {
+                        // prefer to try to parse first if its a variable or we are compressing
+                        // but always fallback on the other one
+                        value = !tryAnonymous && (env.compress || isVariable) ?
+                            (this.value() || this.anonymousValue()) :
+                            (this.anonymousValue() || this.value());
+
+                        important = this.important();
+
+                        // a name returned by this.ruleProperty() is always an array of the form:
+                        // [string-1, ..., string-n, ""] or [string-1, ..., string-n, "+"]
+                        // where each item is a tree.Keyword or tree.Variable
+                        merge = !isVariable && name.pop().value;
+                    }
 
                     if (value && this.end()) {
-                        return new (tree.Rule)(name, value, important, merge, memo, env.currentFileInfo);
+                        forget();
+                        return new (tree.Rule)(name, value, important, merge, startOfRule, env.currentFileInfo);
                     } else {
                         furthest = i;
                         restore();
                         if (value && !tryAnonymous) {
                             return this.rule(true);
                         }
                     }
+                } else {
+                    forget();
                 }
             },
             anonymousValue: function () {
@@ -1546,6 +1622,7 @@ less.Parser = function Parser(env) {
                 if (dir && (path = this.entities.quoted() || this.entities.url())) {
                     features = this.mediaFeatures();
                     if ($char(';')) {
+                        forget();
                         features = features && new(tree.Value)(features);
                         return new(tree.Import)(path, features, options, index, env.currentFileInfo);
                     }
@@ -1742,13 +1819,11 @@ less.Parser = function Parser(env) {
                 }
 
                 if (hasBlock) {
-                    rules = this.block();
-                    if (rules) { 
-                        rules = new(tree.Ruleset)(null, rules);
-                    }
+                    rules = this.blockRuleset();
                 }
 
                 if (rules || (!hasBlock && value && $char(';'))) {
+                    forget();
                     return new(tree.Directive)(name, value, rules, index, env.currentFileInfo, 
                         env.dumpLineNumbers ? getDebugInfo(index, input, env) : null);
                 }

lib/less/tree/detached-ruleset.js

@@ -0,0 +1,20 @@
+(function (tree) {
+
+tree.DetachedRuleset = function (ruleset, frames) {
+    this.ruleset = ruleset;
+    this.frames = frames;
+};
+tree.DetachedRuleset.prototype = {
+    type: "DetachedRuleset",
+    accept: function (visitor) {
+        this.ruleset = visitor.visit(this.ruleset);
+    },
+    eval: function (env) {
+        var frames = this.frames || env.frames.slice(0);
+        return new tree.DetachedRuleset(this.ruleset, frames);
+    },
+    callEval: function (env) {
+        return this.ruleset.eval(this.frames ? new(tree.evalEnv)(env, this.frames.concat(env.frames)) : env);
+    }
+};
+})(require('../tree'));

lib/less/tree/media.js

@@ -147,6 +147,8 @@ tree.Media.prototype = {
       }
     },
     bubbleSelectors: function (selectors) {
+      if (!selectors)
+        return;
       this.rules = [new(tree.Ruleset)(selectors.slice(0), [this.rules[0]])];
     }
 };

lib/less/tree/mixin.js

@@ -103,7 +103,7 @@ tree.mixin.Call.prototype = {
                                 mixin.originalRuleset = mixins[m].originalRuleset || mixins[m];
                             }
                             Array.prototype.push.apply(
-                                  rules, mixin.eval(env, args, this.important).rules);
+                                  rules, mixin.evalCall(env, args, this.important).rules);
                         } catch (e) {
                             throw { message: e.message, index: this.index, filename: this.currentFileInfo.filename, stack: e.stack };
                         }
@@ -150,7 +150,7 @@ tree.mixin.Call.prototype = {
     }
 };
 
-tree.mixin.Definition = function (name, params, rules, condition, variadic) {
+tree.mixin.Definition = function (name, params, rules, condition, variadic, frames) {
     this.name = name;
     this.selectors = [new(tree.Selector)([new(tree.Element)(null, name, this.index, this.currentFileInfo)])];
     this.params = params;
@@ -164,7 +164,7 @@ tree.mixin.Definition = function (name, params, rules, condition, variadic) {
         else                                 { return count; }
     }, 0);
     this.parent = tree.Ruleset.prototype;
-    this.frames = [];
+    this.frames = frames;
 };
 tree.mixin.Definition.prototype = {
     type: "MixinDefinition",
@@ -258,9 +258,12 @@ tree.mixin.Definition.prototype = {
 
         return frame;
     },
-    eval: function (env, args, important) {
+    eval: function (env) {
+        return new tree.mixin.Definition(this.name, this.params, this.rules, this.condition, this.variadic, this.frames || env.frames.slice(0));
+    },
+    evalCall: function (env, args, important) {
         var _arguments = [],
-            mixinFrames = this.frames.concat(env.frames),
+            mixinFrames = this.frames ? this.frames.concat(env.frames) : env.frames,
             frame = this.evalParams(env, new(tree.evalEnv)(env, mixinFrames), args, _arguments),
             rules, ruleset;