Adding field

lib/carto/index.js

@@ -52,7 +52,7 @@ var carto = {
 
 [ 'alpha', 'anonymous', 'call', 'color', 'comment', 'definition', 'dimension',
   'directive', 'element', 'expression', 'filterset', 'filter',
-  'keyword', 'layer', 'mixin', 'operation', 'quoted',
+  'keyword', 'layer', 'mixin', 'operation', 'quoted', 'field',
   'reference', 'rule', 'ruleset', 'selector', 'style', 'url', 'value',
   'variable', 'zoom', 'invalid', 'fontset'
 ].forEach(function(n) {

lib/carto/parser.js

@@ -444,6 +444,14 @@ carto.Parser = function Parser(env) {
                     }
                 },
 
+                field: function() {
+                    var name;
+                    if (input.charAt(i) !== '[') return;
+                    if (name = $(/^\[([^\]]+)\]/)) {
+                        return new tree.Field(name[1]);
+                    }
+                },
+
                 comparison: function() {
                     var str;
                     if (str = $(/^=|!=|<=|>=|<|>/)) {
@@ -461,7 +469,9 @@ carto.Parser = function Parser(env) {
                 //
                 keyword: function() {
                     var k;
-                    if (k = $(/^[A-Za-z-]+[A-Za-z-0-9_]*/)) { return new tree.Keyword(k) }
+                    if (k = $(/^[A-Za-z-]+[A-Za-z-0-9_]*/)) {
+                        return new tree.Keyword(k);
+                    }
                 },
 
                 //
@@ -786,13 +796,14 @@ carto.Parser = function Parser(env) {
                 }
             },
 
+
             filter: function() {
                 save();
                 var key, op, val;
                 if (! $('[')) return;
-                if (key = $(/^[a-zA-Z0-9-_]+/) || $(this.entities.quoted) || $(this.entities.variable)) {
+                if (key = $(this.entities.field) || $(this.entities.literal) || $(this.entities.variable)) {
                     if ((op = $(this.entities.comparison)) &&
-                        (val = $(this.entities.quoted) || $(this.entities.variable) || $(/^[\w-\.]+/))) {
+                        (val = $(this.entities.field)|| $(this.entities.literal) || $(this.entities.variable))) {
                         if (! $(']')) return;
                         return new tree.Filter(key, op, val, memo, env.filename);
                     }

lib/carto/tree/field.js

@@ -0,0 +1,13 @@
+(function(tree) {
+
+tree.Field = function Keyword(value) {
+    this.value = value;
+    this.is = 'field';
+};
+
+tree.Field.prototype = {
+    eval: function() { return this },
+    toString: function() { return '[' + this.value + ']' }
+};
+
+})(require('../tree'));

lib/carto/tree/filter.js

@@ -1,32 +1,19 @@
 (function(tree) {
 
 tree.Filter = function Filter(key, op, val, index, filename) {
-    if (key.is) {
-        this.key = key.value;
-        this._key = key;
-    } else {
-        this.key = key;
-    }
+    this.key = key.value;
+    this._key = key;
+
+    this.val = val.value;
+    this._val = val;
 
     this.op = op;
     this.index = index;
     this.filename = filename;
 
-    if (val.is) {
-        this.val = val.value;
-        this._val = val;
-    } else {
-        this.val = val;
-    }
-
-    if (this.op !== '=' && this.op !== '!=') {
-        this.val = 1 * this.val;
-    }
-
     this.id = this.key + this.op + this.val;
 };
 
-
 // XML-safe versions of comparators
 var opXML = {
     '<': '&lt;',
@@ -38,19 +25,12 @@ var opXML = {
 };
 
 tree.Filter.prototype.toXML = function(env) {
-    if (this.op !== '=' && this.op !== '!=' && isNaN(this.val)) {
-        env.error({
-            message: 'Cannot use operator "' + this.op + '" with value ' + this.val,
-            index: this.index,
-            filename: this.filename
-        });
-    }
+    // Handle variables correctly
     if (this.val.eval) this._val = this.val.eval(env);
     if (this.key.eval) this._key = this.key.eval(env);
-    if (this._key) var key = this._key.toString(false);
-    if (this._val) var val = this._val.toString(this._val.is == 'string');
 
-    return '[' + (key || this.key) + '] ' + opXML[this.op] + ' ' + (val || this.val);
+    return this._key.toString(this._key.is === 'string') + ' ' +
+        opXML[this.op] + ' ' + this._val.toString(this._val.is === 'string');
 };
 
 tree.Filter.prototype.toString = function() {

test/rendering/filters.mss

@@ -1,5 +1,29 @@
-#world[POP2005 > 100.1] {
+#world[[POP2005] > 100.1] {
   polygon-fill: #FFF;
   line-color:#F00;
   line-width: 0.5;
 }
+
+#world[5 > 100.1] {
+  polygon-fill: #FFF;
+}
+
+#world[[POP2005] > [POP2004]] {
+  polygon-fill: #FFF;
+  line-color:#F00;
+  line-width: 0.5;
+}
+
+#world[[POP2005] = "hello"] {
+  polygon-fill: #FFF;
+  line-color:#F00;
+  line-width: 0.5;
+}
+
+/*
+#world[POP2004 = "test"] {
+  polygon-fill: #FFF;
+  line-color:#F00;
+  line-width: 0.5;
+}
+*/