diff --git a/lib/jessie.dart b/lib/jessie.dart
index 543256b..82130dd 100644
--- a/lib/jessie.dart
+++ b/lib/jessie.dart
@@ -2,5 +2,7 @@
 library jessie;
 
 export 'package:jessie/src/field.dart';
+export 'package:jessie/src/filter.dart';
 export 'package:jessie/src/index.dart';
-export 'package:jessie/src/json_path.dart';
+export 'package:jessie/src/neutral.dart';
+export 'package:jessie/src/tokenizer.dart';
diff --git a/lib/src/field.dart b/lib/src/field.dart
index 8c2c791..e24334d 100644
--- a/lib/src/field.dart
+++ b/lib/src/field.dart
@@ -1,6 +1,6 @@
-import 'package:jessie/src/json_path.dart';
+import 'package:jessie/src/filter.dart';
 
-class Field extends JsonPath {
+class Field extends Filter {
   Field(this.name);
 
   final String name;
diff --git a/lib/src/json_path.dart b/lib/src/filter.dart
similarity index 53%
rename from lib/src/json_path.dart
rename to lib/src/filter.dart
index 2b5bb79..733cbc8 100644
--- a/lib/src/json_path.dart
+++ b/lib/src/filter.dart
@@ -1,4 +1,6 @@
-abstract class JsonPath {
+abstract class Filter {
+  const Filter();
+
   /// Applies this JSONPath to the [nodes]
   Iterable call(Iterable nodes);
 
@@ -7,22 +9,18 @@ abstract class JsonPath {
   String toString();
 
   /// A shortcut for `then()`
-  JsonPath operator |(JsonPath other) => then(other);
+  Filter operator |(Filter other) => then(other);
 
   /// Combines this expression with the [other]
-  JsonPath then(JsonPath other) => _Chain(this, other);
-
-  /// Filters the given nodes.
-  /// Returns an Iterable of all elements found
-  Iterable filter(dynamic node) => call([node]);
+  Filter then(Filter other) => _Chain(this, other);
 }
 
-class _Chain extends JsonPath {
+class _Chain extends Filter {
   _Chain(this.first, this.second);
 
-  final JsonPath first;
+  final Filter first;
 
-  final JsonPath second;
+  final Filter second;
 
   @override
   Iterable call(Iterable nodes) => second(first(nodes));
diff --git a/lib/src/index.dart b/lib/src/index.dart
index 2a06054..a571f51 100644
--- a/lib/src/index.dart
+++ b/lib/src/index.dart
@@ -1,6 +1,6 @@
-import 'package:jessie/src/json_path.dart';
+import 'package:jessie/src/filter.dart';
 
-class Index extends JsonPath {
+class Index extends Filter {
   Index(this.index);
 
   final int index;
diff --git a/lib/src/neutral.dart b/lib/src/neutral.dart
new file mode 100644
index 0000000..60dc870
--- /dev/null
+++ b/lib/src/neutral.dart
@@ -0,0 +1,11 @@
+import 'package:jessie/jessie.dart';
+
+class Neutral extends Filter {
+  const Neutral();
+
+  @override
+  Iterable call(Iterable nodes) => nodes;
+
+  @override
+  String toString() => r'$';
+}
diff --git a/lib/src/tokenizer.dart b/lib/src/tokenizer.dart
new file mode 100644
index 0000000..d715a1c
--- /dev/null
+++ b/lib/src/tokenizer.dart
@@ -0,0 +1,129 @@
+List tokenize(String expression) {
+  final tokens = <Token>[];
+  var exp = expression;
+  while (exp.isNotEmpty) {
+    switch (exp[0]) {
+      case r'$':
+        tokens.add(const Root());
+        exp = exp.substring(1);
+        break;
+      case '*':
+        tokens.add(const Asterisk());
+        exp = exp.substring(1);
+        break;
+      case '[':
+        tokens.add(const LeftBracket());
+        exp = exp.substring(1);
+        break;
+      case ']':
+        tokens.add(const RightBracket());
+        exp = exp.substring(1);
+        break;
+      case '.':
+        if (exp.length > 1 && exp[1] == '.') {
+          tokens.add(const DoublePeriod());
+          exp = exp.substring(2);
+        } else {
+          tokens.add(const Period());
+          exp = exp.substring(1);
+        }
+        break;
+      default:
+        if (exp.startsWith(_digit)) {
+          final num = _allDigits.firstMatch(exp).group(0);
+          tokens.add(Number(int.parse(num)));
+          exp = exp.substring(num.length);
+        } else if (exp.startsWith(_char)) {
+          final text = _allAlphanumeric.firstMatch(exp).group(0);
+          tokens.add(Name(text));
+          exp = exp.substring(text.length);
+        } else {
+          throw 'Can not tokenize "$exp"';
+        }
+    }
+  }
+  return tokens;
+}
+
+final _char = RegExp(r'[a-zA-Z]');
+final _allAlphanumeric = RegExp(r'[a-zA-Z][a-zA-Z0-9]+');
+final _digit = RegExp(r'\d');
+final _allDigits = RegExp(r'\d+');
+
+abstract class Token {}
+
+class Root implements Token {
+  const Root();
+
+  @override
+  String toString() => r'$';
+}
+
+class Period implements Token {
+  const Period();
+
+  @override
+  String toString() => '.';
+}
+
+class DoublePeriod implements Token {
+  const DoublePeriod();
+
+  @override
+  String toString() => '..';
+}
+
+class Name implements Token {
+  const Name(this.value);
+
+  final String value;
+
+  @override
+  String toString() => value;
+}
+
+class Number implements Token {
+  const Number(this.value);
+
+  final int value;
+
+  @override
+  String toString() => value.toString();
+}
+
+class Asterisk implements Token {
+  const Asterisk();
+
+  @override
+  String toString() => '*';
+}
+
+class LeftBracket implements Token {
+  const LeftBracket();
+
+  @override
+  String toString() => '[';
+}
+
+class RightBracket implements Token {
+  const RightBracket();
+
+  @override
+  String toString() => ']';
+}
+
+//class LeftParenthesis implements Token {
+//  const LeftParenthesis();
+//}
+//
+//class RightParenthesis implements Token {
+//  const RightParenthesis();
+//}
+//
+//class Colon implements Token {
+//  const Colon();
+//}
+//
+//class Comma implements Token {
+//  const Comma();
+//}
diff --git a/test/functional_test.dart b/test/functional_test.dart
index cc9ca3e..0996551 100644
--- a/test/functional_test.dart
+++ b/test/functional_test.dart
@@ -7,12 +7,43 @@ import 'package:test/test.dart';
 void main() {
   final store = jsonDecode(File('test/store.json').readAsStringSync());
   group('Basic', () {
-    final path = Field('store') | Field('book') | Index(0) | Field('title');
-    test('filtering', () {
+    final path = JsonPath('store.book[0].title');
+    test('Filtering', () {
       expect(path.filter(store).single, 'Sayings of the Century');
     });
     test('toString()', () {
-      expect(path.toString(), "['store']['book'][0]['title']");
+      expect(path.toString(), r"$['store']['book'][0]['title']");
     });
   });
+
+  group('Tokenizer', () {
+    test('Basic', () {
+      expect(tokenize('store.book[0].title').join(), 'store.book[0].title');
+    });
+  });
+}
+
+class JsonPath {
+  factory JsonPath(String path) {
+    final tokens = tokenize(path);
+    if (tokens.isNotEmpty && tokens.first == const Root()) {
+      tokens.removeAt(0);
+    }
+
+    var filter = const Neutral();
+
+    return JsonPath._(
+        Neutral() | Field('store') | Field('book') | Index(0) | Field('title'));
+  }
+
+  JsonPath._(this._filter);
+
+  final Filter _filter;
+
+  /// Filters the given [json].
+  /// Returns an Iterable of all elements found
+  Iterable filter(json) => _filter.call([json]);
+
+  @override
+  String toString() => _filter.toString();
 }