Refactor

README.md

@@ -8,8 +8,7 @@
 - [x] Square-bracket field notation (`['foo']`, `$['"some" \'special\' [chars]']`)
 - [x] Slice (`articles[1:10:2]`)
 - [x] Union (`book[0, 1]`, `book[author, title, price]`)
-- [ ] Basic filtering (`book[?(@.price)]`)
-- [ ] Expressions (`book[?(@.price * @.discount < 10)]`)
+- [ ] Filtering 
 
 
 [JSONPath]: https://goessner.net/articles/JsonPath/

lib/src/ast.dart

@@ -3,33 +3,31 @@ import 'package:json_path/src/node.dart';
 /// The Abstract Syntax Tree
 class AST {
   AST(Iterable<String> tokens) {
-    tokens.skipWhile((token) => token == _root).forEach(_processToken);
+    tokens.skipWhile((_) => _ == r'$').forEach(_processToken);
   }
 
   /// The children of the root node
   Iterable<Node> get children => _stack.last.children;
 
-  static const _root = r'$';
-
-  final _stack = <Node>[Node(_root)];
+  final _stack = <Node>[Node('')];
 
   void _processToken(String token) {
     if (token == '[') {
-      _startBrackets();
+      _start('[]');
     } else if (token == ']') {
-      _finishBrackets();
+      _finish('[]');
     } else {
       _stack.last.children.add(Node(token));
     }
   }
 
-  void _startBrackets() {
-    _stack.add(Node('[]'));
+  void _start(String root) {
+    _stack.add(Node(root));
   }
 
-  void _finishBrackets() {
+  void _finish(String root) {
     final children = <Node>[];
-    while (_stack.last.value != '[]') {
+    while (_stack.last.value != root) {
       children.add(_stack.removeLast());
     }
     final bracketExp = _stack.removeLast();

lib/src/parser.dart

@@ -9,7 +9,7 @@ class Parser {
   /// Builds a selector from the JsonPath [expression]
   Selector parse(String expression) {
     if (expression.isEmpty) throw FormatException('Empty expression');
-    ParserState state = Ready(Root());
+    ParserState state = Ready(RootSelector());
     AST(_tokenize(expression)).children.forEach((node) {
       state = state.process(node);
     });
@@ -21,8 +21,8 @@ class Parser {
 
   static final _tokens = RegExp([
     r'\$', // root
-    r'\[', // open bracket
-    r'\]', // closing bracket
+    r'\[', // left bracket
+    r'\]', // right bracket
     r'\.\.', // recursion
     r'\.', // child
     r'\*', // wildcard

lib/src/parser_state.dart

@@ -29,7 +29,7 @@ class Ready implements ParserState {
   ParserState process(Node node) {
     switch (node.value) {
       case '[]':
-        return Ready(selector.then(brackets(node.children)));
+        return Ready(selector.then(bracketExpression(node.children)));
       case '.':
         return AwaitingField(selector);
       case '..':
@@ -41,35 +41,27 @@ class Ready implements ParserState {
     }
   }
 
-  Selector brackets(List<Node> nodes) {
+  Selector bracketExpression(List<Node> nodes) {
     if (nodes.isEmpty) throw FormatException('Empty brackets');
     if (nodes.length == 1) return singleValueBrackets(nodes.single);
     return multiValueBrackets(nodes);
   }
 
+  Selector singleValueBrackets(Node node) {
+    if (node.isWildcard) return ListWildcard();
+    if (node.isNumber) return Index(node.intValue);
+    if (node.isQuoted) return Field(node.unquoted);
+    throw FormatException('Unexpected bracket expression');
+  }
+
   Selector multiValueBrackets(List<Node> nodes) {
-    if (nodes.any((node) => node.value == ':')) {
-      int first;
-      int last;
-      int step;
-      var colons = 0;
-      nodes.forEach((node) {
-        if (node.value == ':') {
-          colons++;
-          return;
-        }
-        if (colons == 0) {
-          first = node.intValue;
-          return;
-        }
-        if (colons == 1) {
-          last = node.intValue;
-          return;
-        }
-        step = node.intValue;
-      });
-      return Slice(first: first, last: last, step: step);
-    }
+    if (_isSlice(nodes)) return _slice(nodes);
+    return _union(nodes);
+  }
+
+  bool _isSlice(List<Node> nodes) => nodes.any((node) => node.value == ':');
+
+  Selector _union(List<Node> nodes) {
     final filtered = nodes.where((_) => _.value != ',');
     if (nodes.first.isNumber) {
       return ListUnion(filtered.map((_) => _.intValue).toList());
@@ -78,11 +70,27 @@ class Ready implements ParserState {
         filtered.map((_) => _.isQuoted ? _.unquoted : _.value).toList());
   }
 
-  Selector singleValueBrackets(Node node) {
-    if (node.isWildcard) return ListWildcard();
-    if (node.isNumber) return Index(node.intValue);
-    if (node.isQuoted) return Field(node.unquoted);
-    throw FormatException('Unexpected bracket expression');
+  Slice _slice(List<Node> nodes) {
+    int first;
+    int last;
+    int step;
+    var colons = 0;
+    nodes.forEach((node) {
+      if (node.value == ':') {
+        colons++;
+        return;
+      }
+      if (colons == 0) {
+        first = node.intValue;
+        return;
+      }
+      if (colons == 1) {
+        last = node.intValue;
+        return;
+      }
+      step = node.intValue;
+    });
+    return Slice(first: first, last: last, step: step);
   }
 }
 

lib/src/selector/root.dart

@@ -2,8 +2,8 @@ import 'package:json_path/src/result.dart';
 import 'package:json_path/src/selector/selector.dart';
 import 'package:json_path/src/selector/selector_mixin.dart';
 
-class Root with SelectorMixin {
-  const Root();
+class RootSelector with SelectorMixin {
+  const RootSelector();
 
   @override
   Iterable<Result> filter(Iterable<Result> results) =>

test/json_path_test.dart

@@ -247,15 +247,15 @@ void main() {
     });
   });
 
-  group('Arrays', () {
+  group('Lists', () {
     test('Path with an index', () {
       final path = JsonPath(r'$.store.book[0].title');
       expect(path.toString(), r"$['store']['book'][0]['title']");
       expect(path.filter(json).single.value, 'Sayings of the Century');
       expect(path.filter(json).single.path, r"$['store']['book'][0]['title']");
     });
 
-    test('All in array', () {
+    test('All in list', () {
       final path = JsonPath(r'$.store.book[*]');
       expect(path.toString(), r"$['store']['book'][*]");
       expect(path.filter(json).length, 4);