First pass at tilemill-friendly validation

lib/mess/parser.js

@@ -284,6 +284,10 @@ mess.Parser = function Parser(env) {
             root = new tree.Ruleset([], $(this.parsers.primary));
             root.root = true;
 
+            root.getLine = function(index) {
+                return index ? (input.slice(0, index).match(/\n/g) || '').length : null;
+            },
+
             /**
              * Get an array of Ruleset objects, flattened
              * and sorted according to specificitySort
@@ -293,10 +297,11 @@ mess.Parser = function Parser(env) {
 
                 return function(options, variables) {
                     options = options || {};
-                    options.compress = 'compress' in options ?
-                        options.compress : (env.compress || false);
 
-                    var returnErrors = 'returnErrors' in options ? options.returnErrors : (env.returnErrors || false);
+                    var returnErrors = 'returnErrors' in options ?
+                        options.returnErrors :
+                        (env.returnErrors || false);
+
                     env.errors = returnErrors ? [] : null;
 
                     try {

lib/mess/renderer.js

@@ -347,7 +347,7 @@ mess.Renderer = function Renderer(env) {
             }).forEach(function(r) {
                 for (var i = 0; i < r.rules.length; i++) {
                     if (r.rules[i].eval) r.rules[i] = r.rules[i].eval(env);
-                    properties.push(r.rules[i].toString());
+                    properties.push(r.rules[i].toString(env));
                 }
             });
             return properties.join('');

lib/mess/tree/definition.js

@@ -71,15 +71,26 @@ tree.Definition.prototype.unique_rules = function() {
 tree.Definition.prototype.toXML = function(env) {
     if (this._xml) return this._xml;
     var sym = this.symbolizers();
-    if (sym.length !== 1) {
+    if (!env.returnErrors && sym.length !== 1) {
         throw {
             message: 'A single symbolizer is expected'
-            + 'in definition compilation'
+                + 'in definition compilation'
         }
     } else {
         sym = sym[0];
     }
 
+    if (env.returnErrors) {
+        env.error = function(e) {
+            if (env.errors) {
+                env.errors.push(e);
+            }
+            else {
+                throw e;
+            }
+        };
+    }
+
     var symname = sym.charAt(0).toUpperCase()
         + sym.slice(1).replace(/\-./, function(str) {
         return str[1].toUpperCase();
@@ -94,8 +105,7 @@ tree.Definition.prototype.toXML = function(env) {
         }).join('\n      ')
         + '/>';
     
-    var filters = this.selector.combinedFilter();
-
+    var filters = this.selector.combinedFilter(env);
     
     return this._xml = '  <Rule>\n    ' +
         filters + '\n' +

lib/mess/tree/ruleset.js

@@ -9,7 +9,6 @@ tree.Ruleset = function(selectors, rules) {
 tree.Ruleset.prototype = {
     eval: function(env) {
         var ruleset = new tree.Ruleset(this.selectors, this.rules.slice(0));
-
         ruleset.root = this.root;
 
         // push the current ruleset to the frames stack
@@ -112,8 +111,6 @@ tree.Ruleset.prototype = {
         });
         return this._lookups[key] = rules;
     },
-
-
     flatten: function(result, parentSelectors) {
         var selectors = [];
         for (var i = 0; i < this.selectors.length; i++) {

lib/mess/tree/selector.js

@@ -53,12 +53,16 @@ tree.Selector.prototype.layers = function(env) {
     }).join(' ');
 };
 
-tree.Selector.prototype.combinedFilter = function() {
-    var filters = this.zoom.toXML();
+tree.Selector.prototype.combinedFilter = function(env) {
+    var filters = this.zoom ? this.zoom.toXML() : [];
     
     if (this.filters.length) {
         filters.push('<Filter>' + this.filters.map(function(f) {
-            return '(' + f.toXML().trim() + ')';
+            // TODO: this is required to support selectors
+            // that haven't been processed in the render() function.
+            if (f instanceof tree.Filter) {
+                return '(' + f.toXML(env).trim() + ')';
+            }
         }).join(' and ') + '</Filter>');
     }