Creating an ANTLR grammar for Dart, potentially the syntax spec.

tools/spec_parser/SpecParserRunner.java

+// Copyright (c) 2017, 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.
+
+import java.util.Scanner;
+import java.util.List;
+import java.util.ArrayList;
+
+/// Class for `main` which will parse files given as lines on stdio.
+public class SpecParserRunner {
+  public static void main(String[] args) throws Exception {
+    if (args.length != 0) {
+      System.err.println("No command line arguments expected.");
+      System.err.println("Files to parse are accepted on the standard input.");
+      System.exit(1);
+    }
+
+    Scanner scanner = new Scanner(System.in);
+    String[] filenames = new String[1];
+    while (scanner.hasNextLine()) {
+      String filename = scanner.nextLine().trim();
+      filenames[0] = filename;
+      System.out.println("---------- " + filename + " ----------");
+      SpecParser.main(filenames);
+    }
+  }
+}