diff --git a/lib/carto/parser.js b/lib/carto/parser.js
index 5de8b861b..835506219 100644
--- a/lib/carto/parser.js
+++ b/lib/carto/parser.js
@@ -213,28 +213,11 @@ carto.Parser = function Parser(env) {
 
                     // call populates Invalid-caused errors
                     var definitions = this.flatten([], [], env);
-                    definitions.sort(specificitySort);
+                    definitions.sort(tree.specificitySort);
                     return definitions;
                 };
             })();
 
-            // Sort rules by specificity: this function expects selectors to be
-            // split already.
-            //
-            // Written to be used as a .sort(Function);
-            // argument.
-            //
-            // [1, 0, 0, 467] > [0, 0, 1, 520]
-            var specificitySort = function(a, b) {
-                var as = a.specificity;
-                var bs = b.specificity;
-
-                if (as[0] != bs[0]) return bs[0] - as[0];
-                if (as[1] != bs[1]) return bs[1] - as[1];
-                if (as[2] != bs[2]) return bs[2] - as[2];
-                return bs[3] - as[3];
-            };
-
             return root;
         },
 
diff --git a/lib/carto/tree.js b/lib/carto/tree.js
index a8d6db986..02db67535 100644
--- a/lib/carto/tree.js
+++ b/lib/carto/tree.js
@@ -8,3 +8,31 @@ module.exports.find = function (obj, fun) {
     }
     return null;
 };
+
+// Sort rules by specificity: this function expects selectors to be
+// split already.
+//
+// Specificity: [ID, Class, Filters, Zoom, Position in document]
+//
+// Written to be used as a .sort(Function);
+// argument.
+//
+// [1, 0, 0, 467] > [0, 0, 1, 520]
+module.exports.specificitySort = function (a, b) {
+    var as = a.specificity;
+    var bs = b.specificity;
+
+    if (as[0] != bs[0]) { // ID
+        return bs[0] - as[0];
+    }
+    if (as[1] != bs[1]) { // Class
+        return bs[1] - as[1];
+    }
+    if (as[2] != bs[2]) { // Filters
+        return bs[2] - as[2];
+    }
+    if (as[3] != -1 && bs[3] != -1 && as[3] != bs[3]) { // Zoom
+        return bs[4] - as[4];
+    }
+    return bs[4] - as[4]; // Position in document
+};
diff --git a/lib/carto/tree/call.js b/lib/carto/tree/call.js
index 2b917edf0..e24129b94 100644
--- a/lib/carto/tree/call.js
+++ b/lib/carto/tree/call.js
@@ -7,6 +7,7 @@ tree.Call = function Call(name, args, filename, index) {
     this.args = args;
     this.filename = filename;
     this.index = index;
+    this.rule = null;
 };
 
 tree.Call.prototype = {
@@ -105,6 +106,14 @@ tree.Call.prototype = {
         } else {
             return this.name;
         }
+    },
+    setRule: function (rule) {
+        this.rule = rule;
+        _.forEach(this.args, function (a) {
+            if (typeof a.setRule === 'function') {
+                a.setRule(rule);
+            }
+        });
     }
 };
 
diff --git a/lib/carto/tree/color.js b/lib/carto/tree/color.js
index 8165a3557..1c59b8610 100644
--- a/lib/carto/tree/color.js
+++ b/lib/carto/tree/color.js
@@ -29,6 +29,7 @@ tree.Color = function Color(hsl, a, perceptual) {
     } else {
         this.perceptual = false;
     }
+    this.rule = null;
 };
 
 tree.Color.prototype = {
@@ -149,6 +150,10 @@ tree.Color.prototype = {
 
     round: function(value, decimals) {
         return Number(Math.round(value+'e'+decimals)+'e-'+decimals);
+    },
+
+    setRule: function (rule) {
+        this.rule = rule;
     }
 };
 
diff --git a/lib/carto/tree/definition.js b/lib/carto/tree/definition.js
index ecc793750..1840e429f 100644
--- a/lib/carto/tree/definition.js
+++ b/lib/carto/tree/definition.js
@@ -9,7 +9,9 @@ var assert = require('assert'),
 // }
 //
 // The selector can have filters
-tree.Definition = function Definition(selector, rules) {
+tree.Definition = function Definition(selector, rules, env) {
+    var that = this;
+
     this.elements = selector.elements;
     assert.ok(selector.filters instanceof tree.Filterset);
     this.rules = rules;
@@ -19,10 +21,42 @@ tree.Definition = function Definition(selector, rules) {
         this.rules[i].zoom = selector.zoom;
         this.ruleIndex[this.rules[i].updateID()] = true;
     }
+
     this.filters = selector.filters;
+    if (this.filters) {
+        if (_.isArray(this.filters)) {
+            _.forEach(this.filters, function (f) {
+                if (typeof f.setRule === 'function') {
+                    f.setRule(that);
+                }
+            });
+        }
+        else {
+            if (typeof this.filters.setRule === 'function') {
+                this.filters.setRule(that);
+            }
+        }
+    }
+
     this.zoom = selector.zoom;
+
+    if (this.zoom) {
+        if (_.isArray(this.zoom)) {
+            _.forEach(this.zoom, function (f) {
+                if (typeof f.setRule === 'function') {
+                    f.setRule(that);
+                }
+            });
+        }
+        else {
+            if (typeof this.zoom.setRule === 'function') {
+                this.zoom.setRule(that);
+            }
+        }
+    }
+
     this.attachment = selector.attachment || '__default__';
-    this.specificity = selector.specificity();
+    this.specificity = selector.specificity(env);
     this.matchCount = 0;
 
     // special handling for Map selector
diff --git a/lib/carto/tree/dimension.js b/lib/carto/tree/dimension.js
index 4d1e70707..4aee932cf 100644
--- a/lib/carto/tree/dimension.js
+++ b/lib/carto/tree/dimension.js
@@ -10,6 +10,7 @@ tree.Dimension = function Dimension(value, unit, index, filename) {
     this.unit = unit || null;
     this.filename = filename;
     this.index = index;
+    this.rule = null;
 };
 
 tree.Dimension.prototype = {
@@ -96,6 +97,9 @@ tree.Dimension.prototype = {
         //here the operands are either the same (% or undefined or px), or one is undefined and the other is px
         return new tree.Dimension(tree.operate(op, this.value, other.value),
             this.unit || other.unit, this.index, this.filename);
+    },
+    setRule: function (rule) {
+        this.rule = rule;
     }
 };
 
diff --git a/lib/carto/tree/expression.js b/lib/carto/tree/expression.js
index dfe1da038..c381c265a 100644
--- a/lib/carto/tree/expression.js
+++ b/lib/carto/tree/expression.js
@@ -4,6 +4,7 @@ var _ = require('lodash');
 
 tree.Expression = function Expression(value) {
     this.value = value;
+    this.rule = null;
 };
 
 tree.Expression.prototype = {
@@ -33,6 +34,22 @@ tree.Expression.prototype = {
             return mappedVal;
         }
         return mappedVal.join(' ');
+    },
+
+    setRule: function (rule) {
+        this.rule = rule;
+        if (_.isArray(this.value)) {
+            _.forEach(this.value, function (v) {
+                if (typeof v.setRule === 'function') {
+                    v.setRule(rule);
+                }
+            });
+        }
+        else {
+            if (typeof this.value.setRule === 'function') {
+                this.value.setRule(rule);
+            }
+        }
     }
 };
 
diff --git a/lib/carto/tree/field.js b/lib/carto/tree/field.js
index a98b904e1..7cedf414a 100644
--- a/lib/carto/tree/field.js
+++ b/lib/carto/tree/field.js
@@ -2,6 +2,7 @@
 
 tree.Field = function Field(content) {
     this.value = content || '';
+    this.rule = null;
 };
 
 tree.Field.prototype = {
@@ -11,6 +12,12 @@ tree.Field.prototype = {
     },
     'ev': function() {
         return this;
+    },
+    setRule: function (rule) {
+        this.rule = rule;
+        if (typeof this.value.setRule === 'function') {
+            this.value.setRule(rule);
+        }
     }
 };
 
diff --git a/lib/carto/tree/filter.js b/lib/carto/tree/filter.js
index 59dd2d562..5165a60a0 100644
--- a/lib/carto/tree/filter.js
+++ b/lib/carto/tree/filter.js
@@ -8,6 +8,7 @@ tree.Filter = function Filter(key, op, val, index, filename) {
     this.val = val;
     this.index = index;
     this.filename = filename;
+    this.rule = null;
 
     this.id = this.key + this.op + this.val;
 };
@@ -67,4 +68,17 @@ tree.Filter.prototype.toString = function() {
     return '[' + this.id + ']';
 };
 
+tree.Filter.prototype.setRule = function (rule) {
+    this.rule = rule;
+    if (typeof this.key.setRule === 'function') {
+        this.key.setRule(rule);
+    }
+    if (typeof this.op.setRule === 'function') {
+        this.op.setRule(rule);
+    }
+    if (typeof this.val.setRule === 'function') {
+        this.val.setRule(rule);
+    }
+}
+
 })(require('../tree'));
diff --git a/lib/carto/tree/filterset.js b/lib/carto/tree/filterset.js
index 7449bcf67..5b31ff3e5 100644
--- a/lib/carto/tree/filterset.js
+++ b/lib/carto/tree/filterset.js
@@ -1,8 +1,10 @@
 var tree = require('../tree'),
-    util = require('../util');
+    util = require('../util'),
+    _ = require('lodash');
 
 tree.Filterset = function Filterset() {
     this.filters = {};
+    this.rule = null;
 };
 
 tree.Filterset.prototype.toObject = function(env) {
@@ -49,6 +51,7 @@ tree.Filterset.prototype.ev = function(env) {
 
 tree.Filterset.prototype.clone = function() {
     var clone = new tree.Filterset();
+    clone.rule = this.rule;
     for (var id in this.filters) {
         clone.filters[id] = this.filters[id];
     }
@@ -288,3 +291,12 @@ tree.Filterset.prototype.add = function(filter, env) { // eslint-disable-line
         }
     }
 };
+
+tree.Filterset.prototype.setRule = function (rule) {
+    this.rule = rule;
+    _.forEach(this.filters, function (f) {
+        if (typeof f.setRule === 'function') {
+            f.setRule(rule);
+        }
+    });
+}
diff --git a/lib/carto/tree/fontset.js b/lib/carto/tree/fontset.js
index e2cf89845..8b743b3fd 100644
--- a/lib/carto/tree/fontset.js
+++ b/lib/carto/tree/fontset.js
@@ -1,5 +1,7 @@
 (function(tree) {
 
+var _ = require('lodash');
+
 tree._flattenFontArray = function (fonts) {
     var result = [];
 
@@ -29,6 +31,7 @@ tree._getFontSet = function(env, fonts) {
 tree.FontSet = function FontSet(env, fonts) {
     this.fonts = fonts;
     this.name = 'fontset-' + env.effects.length;
+    this.rule = null;
 };
 
 tree.FontSet.prototype.toObject = function(env) { // eslint-disable-line
@@ -48,4 +51,13 @@ tree.FontSet.prototype.toObject = function(env) { // eslint-disable-line
     };
 };
 
+tree.FontSet.prototype.setRule = function (rule) {
+    this.rule = rule;
+    _.forEach(this.fonts, function (f) {
+        if (typeof f.setRule === 'function') {
+            f.setRule(rule);
+        }
+    });
+}
+
 })(require('../tree'));
diff --git a/lib/carto/tree/imagefilter.js b/lib/carto/tree/imagefilter.js
index 99a1fe5ac..130cd1354 100644
--- a/lib/carto/tree/imagefilter.js
+++ b/lib/carto/tree/imagefilter.js
@@ -1,8 +1,11 @@
 (function(tree) {
 
+var _ = require('lodash');
+
 tree.ImageFilter = function ImageFilter(filter, args) {
     this.filter = filter;
     this.args = args || null;
+    this.rule = null;
 };
 
 tree.ImageFilter.prototype = {
@@ -18,5 +21,17 @@ tree.ImageFilter.prototype = {
     }
 };
 
+tree.ImageFilter.prototype.setRule = function (rule) {
+    this.rule = rule;
+    if (typeof this.filter.setRule === 'function') {
+        this.filter.setRule(rule);
+    }
+    _.forEach(this.args, function (a) {
+        if (typeof a.setRule === 'function') {
+            a.setRule(rule);
+        }
+    });
+}
+
 
 })(require('../tree'));
diff --git a/lib/carto/tree/invalid.js b/lib/carto/tree/invalid.js
index ad37a7f61..9fb97cc5c 100644
--- a/lib/carto/tree/invalid.js
+++ b/lib/carto/tree/invalid.js
@@ -7,6 +7,7 @@ tree.Invalid = function Invalid(chunk, index, message, filename) {
     this.index = index;
     this.message = message || "Invalid code: " + this.chunk;
     this.filename = filename;
+    this.rule = null;
 };
 
 tree.Invalid.prototype.is = 'invalid';
@@ -22,4 +23,8 @@ tree.Invalid.prototype.ev = function(env) {
         is: 'undefined'
     };
 };
+
+tree.Invalid.prototype.setRule = function (rule) {
+    this.rule = rule;
+};
 })(require('../tree'));
diff --git a/lib/carto/tree/keyword.js b/lib/carto/tree/keyword.js
index ed317717d..be6559536 100644
--- a/lib/carto/tree/keyword.js
+++ b/lib/carto/tree/keyword.js
@@ -8,10 +8,17 @@ tree.Keyword = function Keyword(value) {
         'false': 'boolean'
     };
     this.is = special[value] ? special[value] : 'keyword';
+    this.rule = null;
 };
 tree.Keyword.prototype = {
     ev: function() { return this; },
     toString: function() { return this.value; }
 };
+tree.Keyword.prototype.setRule = function (rule) {
+    this.rule = rule;
+    if (typeof this.value.setRule === 'function') {
+        this.value.setRule(rule);
+    }
+}
 
 })(require('../tree'));
diff --git a/lib/carto/tree/literal.js b/lib/carto/tree/literal.js
index 5fb6968e4..3a29f61b5 100644
--- a/lib/carto/tree/literal.js
+++ b/lib/carto/tree/literal.js
@@ -6,6 +6,7 @@
 tree.Literal = function Field(content) {
     this.value = content || '';
     this.is = 'field';
+    this.rule = null;
 };
 
 tree.Literal.prototype = {
@@ -17,4 +18,11 @@ tree.Literal.prototype = {
     }
 };
 
+tree.Literal.prototype.setRule = function (rule) {
+    this.rule = rule;
+    if (typeof this.value.setRule === 'function') {
+        this.value.setRule(rule);
+    }
+}
+
 })(require('../tree'));
diff --git a/lib/carto/tree/operation.js b/lib/carto/tree/operation.js
index 473d785e7..9e2617eae 100644
--- a/lib/carto/tree/operation.js
+++ b/lib/carto/tree/operation.js
@@ -2,13 +2,15 @@
 // like 2 + 1.
 (function(tree) {
 
-var util = require('../util');
+var util = require('../util'),
+    _ = require('lodash');
 
 tree.Operation = function Operation(op, operands, index, filename) {
     this.op = op.trim();
     this.operands = operands;
     this.index = index;
     this.filename = filename;
+    this.rule = null;
 };
 
 tree.Operation.prototype.is = 'operation';
@@ -89,6 +91,18 @@ tree.Operation.prototype.toString = function () {
     return this.operands[0].toString() + this.op  + this.operands[1].toString();
 };
 
+tree.Operation.prototype.setRule = function (rule) {
+    this.rule = rule;
+    if (typeof this.op.setRule === 'function') {
+        this.op.setRule(rule);
+    }
+    _.forEach(this.operands, function (o) {
+        if (typeof o.setRule === 'function') {
+            o.setRule(rule);
+        }
+    });
+}
+
 tree.operate = function(op, a, b) {
     switch (op) {
         case '+': return a + b;
diff --git a/lib/carto/tree/quoted.js b/lib/carto/tree/quoted.js
index 0d3045e1e..956da9679 100644
--- a/lib/carto/tree/quoted.js
+++ b/lib/carto/tree/quoted.js
@@ -2,6 +2,7 @@
 
 tree.Quoted = function Quoted(content) {
     this.value = content || '';
+    this.rule = null;
 };
 
 tree.Quoted.prototype = {
@@ -24,6 +25,13 @@ tree.Quoted.prototype = {
 
     operate: function(env, op, other) {
         return new tree.Quoted(tree.operate(op, this.toString(), other.toString(this.contains_field)));
+    },
+
+    setRule: function (rule) {
+        this.rule = rule;
+        if (typeof this.value.setRule === 'function') {
+            this.value.setRule(rule);
+        }
     }
 };
 
diff --git a/lib/carto/tree/rule.js b/lib/carto/tree/rule.js
index 393b67e8b..675bf10f2 100644
--- a/lib/carto/tree/rule.js
+++ b/lib/carto/tree/rule.js
@@ -12,10 +12,23 @@ tree.Rule = function Rule(name, value, index, filename) {
     this.instance = parts.length ? parts[0] : '__default__';
     this.value = (value instanceof tree.Value) ?
         value : new tree.Value([value]);
+
+    if (typeof this.value.setRule === 'function') {
+        this.value.setRule(this);
+    }
+
     this.index = index;
-    this.symbolizer = tree.Reference.symbolizer(this.name);
     this.filename = filename;
     this.variable = (name.charAt(0) === '@');
+
+    if (this.variable) {
+        this.symbolizer = '*';
+    }
+    else {
+        this.symbolizer = tree.Reference.symbolizer(this.name);
+    }
+
+    this.parent = null;
 };
 
 tree.Rule.prototype.is = 'rule';
@@ -29,6 +42,7 @@ tree.Rule.prototype.clone = function() {
     clone.symbolizer = this.symbolizer;
     clone.filename = this.filename;
     clone.variable = this.variable;
+    clone.selectors = this.selectors;
     return clone;
 };
 
@@ -43,7 +57,7 @@ tree.Rule.prototype.toString = function() {
 tree.Rule.prototype.validate = function (env) {
     var valid = true;
 
-    if (!tree.Reference.validSelector(this.name)) {
+    if (!tree.Reference.validSelector(this.name) && !this.variable) {
         var mean = getMean(this.name);
         var mean_message = '';
         if (mean[0][1] < 3) {
@@ -84,7 +98,7 @@ tree.Rule.prototype.validate = function (env) {
 
         if ((this.value instanceof tree.Value) &&
             !tree.Reference.validValue(env, this.name, this.value)) {
-            if (!tree.Reference.selector(this.name)) {
+            if (!tree.Reference.selector(this.name) && !this.variable) {
                 valid = false;
                 util.error(env, {
                     message: 'Unrecognized property: ' +
@@ -92,7 +106,7 @@ tree.Rule.prototype.validate = function (env) {
                     index: this.index,
                     filename: this.filename
                 });
-            } else {
+            } else if (!this.variable) {
                 var typename;
                 if (tree.Reference.selector(this.name).validate) {
                     typename = tree.Reference.selector(this.name).validate;
diff --git a/lib/carto/tree/ruleset.js b/lib/carto/tree/ruleset.js
index 33f4f4316..b0f4a4bc4 100644
--- a/lib/carto/tree/ruleset.js
+++ b/lib/carto/tree/ruleset.js
@@ -3,8 +3,19 @@
 var util = require('../util');
 
 tree.Ruleset = function Ruleset(selectors, rules) {
+    var that = this;
+
     this.selectors = selectors;
     this.rules = rules;
+    this.rules.forEach(function (r) {
+        if (r instanceof tree.Ruleset) {
+            r.parent = that;
+        }
+        if (r instanceof tree.Rule) {
+            r.parent = that;
+        }
+    });
+    this.parent = null;
     // static cache of find() function
     this._lookups = {};
 };
@@ -93,9 +104,12 @@ tree.Ruleset.prototype = {
     },
     flatten: function(result, parents, env) {
         var selectors = [], i, j;
-        if (this.selectors.length === 0) {
-            env.frames = env.frames.concat(this.rules);
-        }
+        // add variables to env.frames
+        this.rules.forEach(function (r) {
+            if (r.variable) {
+                env.frames.push(r);
+            }
+        });
         // evaluate zoom variables on this object.
         this.evZooms(env);
         for (i = 0; i < this.selectors.length; i++) {
@@ -169,7 +183,7 @@ tree.Ruleset.prototype = {
             if (index !== false) {
                 selectors[i].index = index;
             }
-            result.push(new tree.Definition(selectors[i], rules.slice()));
+            result.push(new tree.Definition(selectors[i], rules.slice(), env));
         }
 
         return result;
diff --git a/lib/carto/tree/selector.js b/lib/carto/tree/selector.js
index 76fb5daa3..843bd5508 100644
--- a/lib/carto/tree/selector.js
+++ b/lib/carto/tree/selector.js
@@ -1,26 +1,66 @@
 (function(tree) {
 
+var _ = require('lodash');
+
 tree.Selector = function Selector(filters, zoom, elements, attachment, conditions, index) {
+    var that = this;
+
     this.elements = elements || [];
     this.attachment = attachment;
     this.filters = filters || {};
     this.zoom = typeof zoom !== 'undefined' ? zoom : tree.Zoom.all;
     this.conditions = conditions;
     this.index = index;
+
+    if (this.filters) {
+        if (_.isArray(this.filters)) {
+            _.forEach(this.filters, function (f) {
+                if (typeof f.setRule === 'function') {
+                    f.setRule(that);
+                }
+            });
+        }
+        else {
+            if (typeof this.filters.setRule === 'function') {
+                this.filters.setRule(that);
+            }
+        }
+    }
+
+    if (this.zoom) {
+        if (_.isArray(this.zoom)) {
+            _.forEach(this.zoom, function (f) {
+                if (typeof f.setRule === 'function') {
+                    f.setRule(that);
+                }
+            });
+        }
+        else {
+            if (typeof this.zoom.setRule === 'function') {
+                this.zoom.setRule(that);
+            }
+        }
+    }
 };
 
 // Determine the specificity of this selector
 // based on the specificity of its elements - calling
 // Element.specificity() in order to do so
 //
-// [ID, Class, Filters, Position in document]
-tree.Selector.prototype.specificity = function() {
+// [ID, Class, Filters, Zoom, Position in document]
+tree.Selector.prototype.specificity = function(env) {
+    var zoomVal = -1;
+    // if we would evaluate zooms here we would enter an infinite loop
+    if (!_.isArray(this.zoom)) {
+        zoomVal = this.zoom;
+    }
+
     return this.elements.reduce(function(memo, e) {
-        var spec = e.specificity();
+        var spec = e.specificity(env);
         memo[0] += spec[0];
         memo[1] += spec[1];
         return memo;
-    }, [0, 0, this.conditions, this.index]);
+    }, [0, 0, this.conditions, zoomVal, this.index]);
 };
 
 })(require('../tree'));
diff --git a/lib/carto/tree/url.js b/lib/carto/tree/url.js
index fc8fdb740..76abf13d0 100644
--- a/lib/carto/tree/url.js
+++ b/lib/carto/tree/url.js
@@ -3,6 +3,7 @@
 tree.URL = function URL(val, paths) {
     this.value = val;
     this.paths = paths;
+    this.rule = null;
 };
 
 tree.URL.prototype = {
@@ -12,6 +13,12 @@ tree.URL.prototype = {
     },
     ev: function(ctx) {
         return new tree.URL(this.value.ev(ctx), this.paths);
+    },
+    setRule: function (rule) {
+        this.rule = rule;
+        if (typeof this.value.setRule === 'function') {
+            this.value.setRule(rule);
+        }
     }
 };
 
diff --git a/lib/carto/tree/value.js b/lib/carto/tree/value.js
index 4ecbbfeee..abd53386c 100644
--- a/lib/carto/tree/value.js
+++ b/lib/carto/tree/value.js
@@ -4,6 +4,7 @@ var _ = require('lodash');
 
 tree.Value = function Value(value) {
     this.value = value;
+    this.rule = null;
 };
 
 tree.Value.prototype = {
@@ -39,6 +40,21 @@ tree.Value.prototype = {
         else obj.value = this.value;
         obj.is = this.is;
         return obj;
+    },
+    setRule: function (rule) {
+        this.rule = rule;
+        if (_.isArray(this.value)) {
+            _.forEach(this.value, function (v) {
+                if (typeof v.setRule === 'function') {
+                    v.setRule(rule);
+                }
+            });
+        }
+        else {
+            if (typeof this.value.setRule === 'function') {
+                this.value.setRule(rule);
+            }
+        }
     }
 };
 
diff --git a/lib/carto/tree/variable.js b/lib/carto/tree/variable.js
index abacb820e..6dc5bbc40 100644
--- a/lib/carto/tree/variable.js
+++ b/lib/carto/tree/variable.js
@@ -1,26 +1,121 @@
 (function(tree) {
 
-var util = require('../util');
+    var util = require('../util'),
+        _ = require('lodash');
 
-tree.Variable = function Variable(name, index, filename) {
-    this.name = name;
-    this.index = index;
-    this.filename = filename;
-};
+    var findSelector = function (ruleset) {
+        if (ruleset.selectors.length && ruleset.selectors[0].elements.length) {
+            return ruleset.selectors[0];
+        }
+        else {
+            if (ruleset.parent) {
+                return findSelector(ruleset.parent);
+            }
+            return null;
+        }
+    };
+
+    var findFilter = function (ruleset) {
+        if (ruleset.selectors.length && ruleset.selectors[0].filters) {
+            return ruleset.selectors[0].filters;
+        }
+        else {
+            if (ruleset.parent) {
+                return findFilter(ruleset.parent);
+            }
+            return null;
+        }
+    };
 
-tree.Variable.prototype = {
-    is: 'variable',
-    toString: function() {
+    tree.Variable = function Variable(name, index, filename) {
+        this.name = name;
+        this.index = index;
+        this.filename = filename;
+        this.rule = null;
+    };
+
+    tree.Variable.prototype.is = 'variable';
+
+    tree.Variable.prototype.toString = function() {
         return this.name;
-    },
-    ev: function(env) {
+    };
+
+    tree.Variable.prototype.ev = function (env) {
+        var that = this,
+            variableDefs = [],
+            ruleSpecificity = null;
+
         if (this._css) return this._css;
 
-        var thisframe = env.frames.filter(function(f) {
-            return f.name == this.name;
-        }.bind(this));
-        if (thisframe.length) {
-            return thisframe[thisframe.length - 1].value.ev(env);
+        _.forEach(_.filter(env.frames, function (f) {
+            return f.name == that.name;
+        }), function (f) {
+            var selector = findSelector(f.parent),
+                specificity = [0, 0, 0, tree.Zoom.all, f.index],
+                parentSelectorSpecificity = null;
+
+            if (f.parent.selectors.length) {
+                parentSelectorSpecificity = f.parent.selectors[0].specificity(env);
+            }
+
+            if (selector) {
+                selector = selector.elements;
+                specificity = selector[0].specificity(env);
+                if (specificity.length == 2 && parentSelectorSpecificity) {
+                    specificity = [
+                        specificity[0],
+                        specificity[1],
+                        parentSelectorSpecificity[2],
+                        parentSelectorSpecificity[3],
+                        parentSelectorSpecificity[4]
+                    ];
+                }
+            }
+
+            variableDefs.push({
+                selector: selector,
+                filter: findFilter(f.parent),
+                specificity: specificity,
+                rule: f
+            });
+        });
+        if (variableDefs.length) {
+            variableDefs.sort(tree.specificitySort);
+            var rSpec = null;
+
+            if (this.rule instanceof tree.Selector ||
+                this.rule instanceof tree.Definition) {
+                if (typeof this.rule.specificity === 'function') {
+                    rSpec = this.rule.specificity(env);
+                }
+                else {
+                    rSpec = this.rule.specificity;
+                }
+
+                ruleSpecificity = {
+                    specificity: rSpec
+                };
+            }
+            else {
+                if (this.rule.parent.selectors.length) {
+                    var pSpec = findSelector(this.rule.parent).specificity(env);
+
+                    rSpec = this.rule.parent.selectors[0].specificity(env);
+                    ruleSpecificity = {
+                        specificity: [pSpec[0], pSpec[1], rSpec[2], rSpec[3], rSpec[4]]
+                    };
+                }
+                else {
+                    ruleSpecificity = {
+                        specificity: [0, 0, 0, tree.Zoom.all, this.rule.index]
+                    };
+                }
+            }
+
+            for (var i = 0; tree.specificitySort(variableDefs[i],
+                ruleSpecificity) < 0 && i < variableDefs.length; i++);
+
+            return variableDefs[i].rule.value.ev(env);
         } else {
             util.error(env, {
                 message: 'variable ' + this.name + ' is undefined',
@@ -32,7 +127,10 @@ tree.Variable.prototype = {
                 value: 'undefined'
             };
         }
-    }
-};
+    };
+
+    tree.Variable.prototype.setRule = function (rule) {
+        this.rule = rule;
+    };
 
 })(require('../tree'));
diff --git a/lib/carto/tree/zoom.js b/lib/carto/tree/zoom.js
index 50b39c20c..364ffe4d8 100644
--- a/lib/carto/tree/zoom.js
+++ b/lib/carto/tree/zoom.js
@@ -9,6 +9,7 @@ tree.Zoom = function(op, value, index, filename) {
     this.value = value;
     this.index = index;
     this.filename = filename;
+    this.rule = null;
 };
 
 tree.Zoom.prototype.setZoom = function(zoom) {
@@ -126,3 +127,13 @@ tree.Zoom.prototype.toString = function() {
     }
     return str;
 };
+
+tree.Zoom.prototype.setRule = function (rule) {
+    this.rule = rule;
+    if (typeof this.op.setRule === 'function') {
+        this.op.setRule(rule);
+    }
+    if (typeof this.value.setRule === 'function') {
+        this.value.setRule(rule);
+    }
+};
diff --git a/test/rendering/issue_461.mml b/test/rendering/issue_461.mml
new file mode 100644
index 000000000..2496fc4b5
--- /dev/null
+++ b/test/rendering/issue_461.mml
@@ -0,0 +1,10 @@
+{
+  "Stylesheet": [
+    "issue_461.mss"
+  ],
+  "Layer": [
+    {
+      "id": "world"
+    }
+  ]
+}
diff --git a/test/rendering/issue_461.mss b/test/rendering/issue_461.mss
new file mode 100644
index 000000000..60652294a
--- /dev/null
+++ b/test/rendering/issue_461.mss
@@ -0,0 +1,10 @@
+@var: 'foo';
+
+#world {
+  @var: 'oof';
+  [zoom >= 5] {
+      @var: 'roof';
+  }
+  text-face-name: 'Arial';
+  text-name: @var + 'bar';
+}
diff --git a/test/rendering/issue_461.result b/test/rendering/issue_461.result
new file mode 100644
index 000000000..a7e51da4a
--- /dev/null
+++ b/test/rendering/issue_461.result
@@ -0,0 +1,18 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!DOCTYPE Map[]>
+<Map>
+<Style name="world" filter-mode="first" >
+  <Rule>
+    <MaxScaleDenominator>25000000</MaxScaleDenominator>
+    <TextSymbolizer face-name="Arial" text="roofbar" />
+  </Rule>
+  <Rule>
+    <MinScaleDenominator>25000000</MinScaleDenominator>
+    <TextSymbolizer face-name="Arial" text="oofbar" />
+  </Rule>
+</Style>
+<Layer name="world">
+    <StyleName>world</StyleName>
+</Layer>
+
+</Map>
diff --git a/test/specificity/classes.result b/test/specificity/classes.result
index 0e41a46bc..7dcf85f1a 100644
--- a/test/specificity/classes.result
+++ b/test/specificity/classes.result
@@ -1,9 +1,9 @@
 [
-    {"elements":[".foo",".bar",".baz"],"specificity":[0,3,0,29],"matchCount": 0},
-    {"elements":[".foo",".baz"],"specificity":[0,2,0,68],"matchCount": 0},
-    {"elements":[".baz",".foo"],"specificity":[0,2,0,55],"matchCount": 0},
-    {"elements":[".baz",".bar"],"specificity":[0,2,0,0],"matchCount": 0},
-    {"elements":[".baz"],"specificity":[0,1,0,47],"matchCount": 0},
-    {"elements":[".bar"],"specificity":[0,1,0,21],"matchCount": 0},
-    {"elements":[".foo"],"specificity":[0,1,0,13],"matchCount": 0}
+    {"elements":[".foo",".bar",".baz"],"specificity":[0,3,0,67108863,29],"matchCount": 0},
+    {"elements":[".foo",".baz"],"specificity":[0,2,0,67108863,68],"matchCount": 0},
+    {"elements":[".baz",".foo"],"specificity":[0,2,0,67108863,55],"matchCount": 0},
+    {"elements":[".baz",".bar"],"specificity":[0,2,0,67108863,0],"matchCount": 0},
+    {"elements":[".baz"],"specificity":[0,1,0,67108863,47],"matchCount": 0},
+    {"elements":[".bar"],"specificity":[0,1,0,67108863,21],"matchCount": 0},
+    {"elements":[".foo"],"specificity":[0,1,0,67108863,13],"matchCount": 0}
 ]
diff --git a/test/specificity/demo.result b/test/specificity/demo.result
index a36e3ed3b..5c755286b 100644
--- a/test/specificity/demo.result
+++ b/test/specificity/demo.result
@@ -1,10 +1,10 @@
 [
-    {"elements":["#countries",".foo",".bar",".baz"],"specificity":[1,3,0,241],"matchCount": 0},
-    {"elements":["#countries",".countries",".two"],"specificity":[1,2,0,149],"matchCount": 0},
-    {"elements":["#world"],"filters":["[NAME]=United States","[BLUE]=red"],"specificity":[1,0,2,90],"matchCount": 0},
-    {"elements":["#world"],"filters":["[NAME]=United States"],"specificity":[1,0,1,66],"matchCount": 0},
-    {"elements":["#countries"],"specificity":[1,0,0,241],"matchCount": 0},
-    {"elements":["#countries"],"specificity":[1,0,0,194],"matchCount": 0},
-    {"elements":["#world"],"specificity":[1,0,0,194],"matchCount": 0},
-    {"elements":["#world"],"specificity":[1,0,0,11],"matchCount": 0}
+    {"elements":["#countries",".foo",".bar",".baz"],"specificity":[1,3,0,67108863,241],"matchCount": 0},
+    {"elements":["#countries",".countries",".two"],"specificity":[1,2,0,67108863,149],"matchCount": 0},
+    {"elements":["#world"],"filters":["[NAME]=United States","[BLUE]=red"],"specificity":[1,0,2,67108863,90],"matchCount": 0},
+    {"elements":["#world"],"filters":["[NAME]=United States"],"specificity":[1,0,1,67108863,66],"matchCount": 0},
+    {"elements":["#countries"],"specificity":[1,0,0,67108863,241],"matchCount": 0},
+    {"elements":["#countries"],"specificity":[1,0,0,67108863,194],"matchCount": 0},
+    {"elements":["#world"],"specificity":[1,0,0,67108863,194],"matchCount": 0},
+    {"elements":["#world"],"specificity":[1,0,0,67108863,11],"matchCount": 0}
 ]
diff --git a/test/specificity/filters_and_ids.result b/test/specificity/filters_and_ids.result
index abe3dcebf..d8568c960 100644
--- a/test/specificity/filters_and_ids.result
+++ b/test/specificity/filters_and_ids.result
@@ -1,8 +1,8 @@
 [
-    {"elements":["#world","#countries"],"filters":["[NAME]=United States"],"specificity":[2,0,1,94],"matchCount": 0},
-    {"elements":["#world"],"filters":["[NAME]=United States"],"zoom":"......XXXXXXXXXXXXXXXXXXXX","specificity":[1,0,2,60],"matchCount": 0},
-    {"elements":["#world"],"filters":["[NAME]=United States"],"specificity":[1,0,1,33],"matchCount": 0},
-    {"elements":["#world"],"filters":["[NAME]=Canada"],"specificity":[1,0,1,7],"matchCount": 0},
-    {"elements":[],"zoom":"......XXXXXXXXXXXXXXXXXXXX","specificity":[0,0,1,146],"matchCount": 0},
-    {"elements":[],"filters":["[NAME]=United States"],"specificity":[0,0,1,120],"matchCount": 0}
+    {"elements":["#world","#countries"],"filters":["[NAME]=United States"],"specificity":[2,0,1,67108863,94],"matchCount": 0},
+    {"elements":["#world"],"filters":["[NAME]=United States"],"zoom":"......XXXXXXXXXXXXXXXXXXXX","specificity":[1,0,2,67108800,60],"matchCount": 0},
+    {"elements":["#world"],"filters":["[NAME]=United States"],"specificity":[1,0,1,67108863,33],"matchCount": 0},
+    {"elements":["#world"],"filters":["[NAME]=Canada"],"specificity":[1,0,1,67108863,7],"matchCount": 0},
+    {"elements":[],"zoom":"......XXXXXXXXXXXXXXXXXXXX","specificity":[0,0,1,67108800,146],"matchCount": 0},
+    {"elements":[],"filters":["[NAME]=United States"],"specificity":[0,0,1,67108863,120],"matchCount": 0}
 ]
diff --git a/test/specificity/issue60.result b/test/specificity/issue60.result
index f24f92a94..01b8a46ba 100644
--- a/test/specificity/issue60.result
+++ b/test/specificity/issue60.result
@@ -1,6 +1,6 @@
 [
-    {"elements":["#world"],"filters":["[OBJECTID]=12"],"specificity":[1,0,1,131],"matchCount": 0},
-    {"elements":["#world"],"filters":["[NET_INFLOW]>-10000"],"specificity":[1,0,1,83],"matchCount": 0},
-    {"elements":["#world"],"filters":["[NET_INFLOW]>-30000"],"specificity":[1,0,1,35],"matchCount": 0},
-    {"elements":["#world"],"specificity":[1,0,0,0],"matchCount": 0}
+    {"elements":["#world"],"filters":["[OBJECTID]=12"],"specificity":[1,0,1,67108863,131],"matchCount": 0},
+    {"elements":["#world"],"filters":["[NET_INFLOW]>-10000"],"specificity":[1,0,1,67108863,83],"matchCount": 0},
+    {"elements":["#world"],"filters":["[NET_INFLOW]>-30000"],"specificity":[1,0,1,67108863,35],"matchCount": 0},
+    {"elements":["#world"],"specificity":[1,0,0,67108863,0],"matchCount": 0}
 ]