Move frog/leg to lib/compiler/implementation.

frog/leg/tree_validator.dart

-// Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
-// for details. All rights reserved. Use of this source code is governed by a
-// BSD-style license that can be found in the LICENSE file.
-
-class TreeValidatorTask extends CompilerTask {
-  TreeValidatorTask(Compiler compiler) : super(compiler);
-
-  void validate(Node tree) {
-    assert(check(tree));
-  }
-
-  bool check(Node tree) {
-    List<InvalidNodeError> errors = [];
-    void report(node, message) {
-      final error = new InvalidNodeError(node, message);
-      errors.add(error);
-      compiler.reportWarning(node, message);
-    };
-    final validator = new ValidatorVisitor(report);
-    tree.accept(new TraversingVisitor(validator));
-
-    return errors.isEmpty();
-  }
-}
-
-class ValidatorVisitor extends AbstractVisitor {
-  final Function reportInvalidNode;
-
-  ValidatorVisitor(Function this.reportInvalidNode);
-
-  expect(Node node, bool test, [message]) {
-    if (!test) reportInvalidNode(node, message);
-  }
-
-  visitNode(Node node) {}
-
-  visitSendSet(SendSet node) {
-    final selector = node.selector;
-    final name = node.assignmentOperator.source.stringValue;
-    final arguments = node.arguments;
-
-    expect(node, arguments !== null);
-    expect(node, selector is Identifier, 'selector is not assignable');
-    if (name === '++' || name === '--') {
-      expect(node, node.assignmentOperator is Operator);
-      if (node.isIndex) {
-        expect(node.arguments.tail.head, node.arguments.tail.isEmpty());
-      } else {
-        expect(node.arguments.head, node.arguments.isEmpty());
-      }
-    } else {
-      expect(node, !node.arguments.isEmpty());
-    }
-  }
-}
-
-class InvalidNodeError {
-  final Node node;
-  final String message;
-  InvalidNodeError(this.node, [this.message]);
-
-  toString() {
-    String nodeString = new Unparser(true).unparse(node);
-    String result = 'invalid node: $nodeString';
-    if (message !== null) result = '$result ($message)';
-    return result;
-  }
-}