Correct comparison operators.

Author: RubenVerborgh

lib/util/SparqlExpressionEvaluator.js

@@ -158,6 +158,7 @@ operators = {
 };
 
 // Tag all operators that expect their arguments to be numeric
+// TODO: Comparison operators can take simple literals and strings as well
 [
   '+', '-', '*', '/', '<', '<=', '>', '>=',
   'http://www.w3.org/2001/XMLSchema#double',
@@ -174,14 +175,15 @@ operators = {
 
 // Tag all operators that have numeric results
 [
-  '+', '-', '*', '/', '<', '<=', '>', '>=',
+  '+', '-', '*', '/',
 ].forEach(function (operatorName) {
-  operators[operatorName].type = operators[operatorName].resultType = 'numeric';
+  operators[operatorName].resultType = 'numeric';
 });
 
 // Tag all operators that have boolean results
 [
-  '!', '&&', '||', '=', '<', '<=', '>', '>=', 'langmatches', 'contains', 'regex',
+  '!', '&&', '||', '=', '!=', '<', '<=', '>', '>=',
+  'langmatches', 'contains', 'regex',
 ].forEach(function (operatorName) {
   operators[operatorName].resultType = 'boolean';
 });