diff --git a/src/ol/expression/expression.js b/src/ol/expression/expression.js
index b309730135..cee19e79c3 100644
--- a/src/ol/expression/expression.js
+++ b/src/ol/expression/expression.js
@@ -1,10 +1,7 @@
-goog.provide('ol.expression.BooleanLiteral');
 goog.provide('ol.expression.Expression');
 goog.provide('ol.expression.Identifier');
+goog.provide('ol.expression.Literal');
 goog.provide('ol.expression.Not');
-goog.provide('ol.expression.NullLiteral');
-goog.provide('ol.expression.NumericLiteral');
-goog.provide('ol.expression.StringLiteral');
 
 
 /**
@@ -28,40 +25,12 @@ ol.expression.Expression = function() {};
  *
  * @param {Object} scope Evaluation scope.  All properties of this object
  *     will be available as variables when evaluating the expression.
- * @return {string|number|boolean|null} Result of the expression.
+ * @return {*} Result of the expression.
  */
 ol.expression.Expression.prototype.evaluate = goog.abstractMethod;
 
 
 
-/**
- * A boolean literal expression (e.g. `true`).
- *
- * @constructor
- * @extends {ol.expression.Expression}
- * @param {boolean} value A boolean value.
- */
-ol.expression.BooleanLiteral = function(value) {
-
-  /**
-   * @type {boolean}
-   * @private
-   */
-  this.value_ = value;
-
-};
-goog.inherits(ol.expression.BooleanLiteral, ol.expression.Expression);
-
-
-/**
- * @inheritDoc
- */
-ol.expression.BooleanLiteral.prototype.evaluate = function(scope) {
-  return this.value_;
-};
-
-
-
 /**
  * An identifier expression (e.g. `foo`).
  *
@@ -90,6 +59,34 @@ ol.expression.Identifier.prototype.evaluate = function(scope) {
 
 
 
+/**
+ * A literal expression (e.g. `"chicken"`, `42`, `true`, `null`).
+ *
+ * @constructor
+ * @extends {ol.expression.Expression}
+ * @param {string|number|boolean|null} value A literal value.
+ */
+ol.expression.Literal = function(value) {
+
+  /**
+   * @type {string|number|boolean|null}
+   * @private
+   */
+  this.value_ = value;
+
+};
+goog.inherits(ol.expression.Literal, ol.expression.Expression);
+
+
+/**
+ * @inheritDoc
+ */
+ol.expression.Literal.prototype.evaluate = function(scope) {
+  return this.value_;
+};
+
+
+
 /**
  * A logical not expression (e.g. `!foo`).
  *
@@ -116,78 +113,3 @@ ol.expression.Not.prototype.evaluate = function(scope) {
   return !this.expr_.evaluate(scope);
 };
 
-
-
-/**
- * A numeric literal expression (e.g. `42`).
- *
- * @constructor
- * @extends {ol.expression.Expression}
- * @param {number} value A numeric value.
- */
-ol.expression.NumericLiteral = function(value) {
-
-  /**
-   * @type {number}
-   * @private
-   */
-  this.value_ = value;
-
-};
-goog.inherits(ol.expression.NumericLiteral, ol.expression.Expression);
-
-
-/**
- * @inheritDoc
- */
-ol.expression.NumericLiteral.prototype.evaluate = function(scope) {
-  return this.value_;
-};
-
-
-
-/**
- * A null literal expression (i.e. `null`).
- *
- * @constructor
- * @extends {ol.expression.Expression}
- */
-ol.expression.NullLiteral = function() {
-};
-goog.inherits(ol.expression.NullLiteral, ol.expression.Expression);
-
-
-/**
- * @inheritDoc
- */
-ol.expression.NullLiteral.prototype.evaluate = function(scope) {
-  return null;
-};
-
-
-
-/**
- * A string literal expression (e.g. `"chicken"`).
- *
- * @constructor
- * @extends {ol.expression.Expression}
- * @param {string} value A string.
- */
-ol.expression.StringLiteral = function(value) {
-
-  /**
-   * @type {string}
-   * @private
-   */
-  this.value_ = value;
-
-};
-goog.inherits(ol.expression.StringLiteral, ol.expression.Expression);
-
-
-/**
- * @inheritDoc
- */
-ol.expression.StringLiteral.prototype.evaluate = function(scope) {
-  return this.value_;
-};
diff --git a/src/ol/expression/parser.js b/src/ol/expression/parser.js
index 632cf24674..33de610eb0 100644
--- a/src/ol/expression/parser.js
+++ b/src/ol/expression/parser.js
@@ -2,14 +2,11 @@ goog.provide('ol.expression.Parser');
 
 goog.require('goog.asserts');
 
-goog.require('ol.expression.BooleanLiteral');
 goog.require('ol.expression.Expression');
 goog.require('ol.expression.Identifier');
 goog.require('ol.expression.Lexer');
+goog.require('ol.expression.Literal');
 goog.require('ol.expression.Not');
-goog.require('ol.expression.NullLiteral');
-goog.require('ol.expression.NumericLiteral');
-goog.require('ol.expression.StringLiteral');
 goog.require('ol.expression.Token');
 goog.require('ol.expression.TokenType');
 
@@ -159,24 +156,11 @@ ol.expression.Parser.prototype.createIdentifier_ = function(name) {
  * Create a literal expression.
  *
  * @param {string|number|boolean|null} value Literal value.
- * @return {ol.expression.StringLiteral|ol.expression.NumericLiteral|
- *          ol.expression.BooleanLiteral|ol.expression.NullLiteral} The
- *     expression.
+ * @return {ol.expression.Literal} The literal expression.
  * @private
  */
 ol.expression.Parser.prototype.createLiteral_ = function(value) {
-  var expr;
-  if (goog.isString(value)) {
-    expr = new ol.expression.StringLiteral(value);
-  } else if (goog.isNumber(value)) {
-    expr = new ol.expression.NumericLiteral(value);
-  } else if (goog.isBoolean(value)) {
-    expr = new ol.expression.BooleanLiteral(value);
-  } else {
-    goog.asserts.assert(goog.isNull(value));
-    expr = new ol.expression.NullLiteral();
-  }
-  return expr;
+  return new ol.expression.Literal(value);
 };
 
 
diff --git a/test/spec/ol/expression/expression.test.js b/test/spec/ol/expression/expression.test.js
index 60a2838abc..99fbc234f9 100644
--- a/test/spec/ol/expression/expression.test.js
+++ b/test/spec/ol/expression/expression.test.js
@@ -1,19 +1,6 @@
 goog.provide('ol.test.expression.Expression');
 
 
-describe('ol.expression.BooleanLiteral', function() {
-
-  describe('constructor', function() {
-    it('creates a new expression', function() {
-      var expr = new ol.expression.BooleanLiteral(true);
-      expect(expr).to.be.a(ol.expression.Expression);
-      expect(expr).to.be.a(ol.expression.BooleanLiteral);
-    });
-  });
-
-});
-
-
 describe('ol.expression.Identifier', function() {
 
   describe('constructor', function() {
@@ -24,62 +11,115 @@ describe('ol.expression.Identifier', function() {
     });
   });
 
+  describe('#evaluate()', function() {
+    it('returns a number from the scope', function() {
+      var expr = new ol.expression.Identifier('foo');
+      expect(expr.evaluate({foo: 42})).to.be(42);
+    });
+
+    it('returns a string from the scope', function() {
+      var expr = new ol.expression.Identifier('foo');
+      expect(expr.evaluate({foo: 'chicken'})).to.be('chicken');
+    });
+
+    it('returns a boolean from the scope', function() {
+      var expr = new ol.expression.Identifier('bar');
+      expect(expr.evaluate({bar: false})).to.be(false);
+      expect(expr.evaluate({bar: true})).to.be(true);
+    });
+
+    it('returns a null from the scope', function() {
+      var expr = new ol.expression.Identifier('nada');
+      expect(expr.evaluate({nada: null})).to.be(null);
+    });
+
+    it('works for unicode identifiers', function() {
+      var expr = new ol.expression.Identifier('\u03c0');
+      expect(expr.evaluate({'\u03c0': Math.PI})).to.be(Math.PI);
+    });
+  });
+
 });
 
+describe('ol.expression.Literal', function() {
+
+  describe('constructor', function() {
+    it('creates a new expression', function() {
+      var expr = new ol.expression.Literal(true);
+      expect(expr).to.be.a(ol.expression.Expression);
+      expect(expr).to.be.a(ol.expression.Literal);
+    });
+  });
+
+  describe('#evaluate()', function() {
+    it('works for numeric literal', function() {
+      var expr = new ol.expression.Literal(42e-11);
+      expect(expr.evaluate({})).to.be(4.2e-10);
+    });
+
+    it('works for string literal', function() {
+      var expr = new ol.expression.Literal('asdf');
+      expect(expr.evaluate({})).to.be('asdf');
+    });
+
+    it('works for boolean literal', function() {
+      var expr = new ol.expression.Literal(true);
+      expect(expr.evaluate({})).to.be(true);
+    });
+
+    it('works for null literal', function() {
+      var expr = new ol.expression.Literal(null);
+      expect(expr.evaluate({})).to.be(null);
+    });
+  });
+});
+
+
 describe('ol.expression.Not', function() {
 
   describe('constructor', function() {
     it('creates a new expression', function() {
       var expr = new ol.expression.Not(
-          new ol.expression.BooleanLiteral(true));
+          new ol.expression.Literal(true));
       expect(expr).to.be.a(ol.expression.Expression);
       expect(expr).to.be.a(ol.expression.Not);
     });
   });
 
-});
+  describe('#evaluate()', function() {
+    it('returns the logical complement', function() {
+      var expr = new ol.expression.Not(new ol.expression.Literal(true));
+      expect(expr.evaluate({})).to.be(false);
 
-describe('ol.expression.NullLiteral', function() {
-
-  describe('constructor', function() {
-    it('creates a new expression', function() {
-      var expr = new ol.expression.NullLiteral();
-      expect(expr).to.be.a(ol.expression.Expression);
-      expect(expr).to.be.a(ol.expression.NullLiteral);
+      expr = new ol.expression.Not(new ol.expression.Literal(false));
+      expect(expr.evaluate({})).to.be(true);
     });
-  });
 
-});
-
-describe('ol.expression.NumericLiteral', function() {
-
-  describe('constructor', function() {
-    it('creates a new expression', function() {
-      var expr = new ol.expression.NumericLiteral(42);
-      expect(expr).to.be.a(ol.expression.Expression);
-      expect(expr).to.be.a(ol.expression.NumericLiteral);
+    it('negates a truthy string', function() {
+      var expr = new ol.expression.Not(new ol.expression.Literal('asdf'));
+      expect(expr.evaluate({})).to.be(false);
     });
-  });
 
-});
+    it('negates a falsy string', function() {
+      var expr = new ol.expression.Not(new ol.expression.Literal(''));
+      expect(expr.evaluate({})).to.be(true);
+    });
 
-describe('ol.expression.StringLiteral', function() {
+    it('negates a truthy number', function() {
+      var expr = new ol.expression.Not(new ol.expression.Literal(42));
+      expect(expr.evaluate({})).to.be(false);
+    });
 
-  describe('constructor', function() {
-    it('creates a new expression', function() {
-      var expr = new ol.expression.StringLiteral('bar');
-      expect(expr).to.be.a(ol.expression.Expression);
-      expect(expr).to.be.a(ol.expression.StringLiteral);
+    it('negates a falsy number', function() {
+      var expr = new ol.expression.Not(new ol.expression.Literal(NaN));
+      expect(expr.evaluate({})).to.be(true);
     });
   });
 
 });
 
 
-goog.require('ol.expression.BooleanLiteral');
 goog.require('ol.expression.Expression');
 goog.require('ol.expression.Identifier');
+goog.require('ol.expression.Literal');
 goog.require('ol.expression.Not');
-goog.require('ol.expression.NullLiteral');
-goog.require('ol.expression.NumericLiteral');
-goog.require('ol.expression.StringLiteral');