pkg/analyzer: fix formatter bin crash due to empty selection flag

pkg/analyzer/bin/formatter.dart

Index: pkg/analyzer/bin/formatter.dart
diff --git a/pkg/analyzer/bin/formatter.dart b/pkg/analyzer/bin/formatter.dart
index 0466f40df5042446743cfcedab6981d78ed04335..01eb5306a2ed26b2938325e441a1ec879a34b50b 100755
--- a/pkg/analyzer/bin/formatter.dart
+++ b/pkg/analyzer/bin/formatter.dart
@@ -18,7 +18,7 @@ final dartFileRegExp = new RegExp(r'^[^.].*\.dart$', caseSensitive: false);
 final argParser = _initArgParser();
 final defaultSelection = new Selection(-1, -1);
 
-var formatterSettings;
+FormatterOptions formatterSettings;
 
 CodeKind kind;
 bool machineFormat;
@@ -39,7 +39,7 @@ const MAX_LINE_FLAG = 'max_line_length';
 const FOLLOW_LINKS = false;
 
 
-main(args) {
+main(List<String> args) {

[pquitslund, 2014/02/10 04:01:50]

Is this ever NOT a List of Strings?  What's the benefit of declaring it?

   var options = argParser.parse(args);
   if (options['help']) {
     _printUsage();
@@ -56,7 +56,7 @@ main(args) {
   }
 }
 
-_readOptions(options) {
+_readOptions(ArgResults options) {

[pquitslund, 2014/02/10 04:01:50]

Really?  It's like you're provoking me... ;)  Surely you don't really think all
private methods should be typed?  I thought the contract was only with public
APIs?

   kind = _parseKind(options[KIND_FLAG]);
   machineFormat = options[MACHINE_FLAG];
   overwriteFileContents = options[WRITE_FLAG];
@@ -66,7 +66,7 @@ _readOptions(options) {
           pageWidth: _parseLineLength(options[MAX_LINE_FLAG]));
 }
 
-CodeKind _parseKind(kindOption) {
+CodeKind _parseKind(String kindOption) {

[pquitslund, 2014/02/10 04:01:50]

OK, and especially here.  Isn't it obvious from the switch that this is a
String?  What's the benefit of the explicit type?

   switch(kindOption) {
     case 'stmt' :
       return CodeKind.STATEMENT;
@@ -90,15 +90,15 @@ int _parseLineLength(String lengthOption) {
 }
 
 
-Selection _parseSelection(selectionOption) {
-  if (selectionOption != null) {
-    var units = selectionOption.split(',');
-    if (units.length == 2) {
-      var offset = _toInt(units[0]);
-      var length = _toInt(units[1]);
-      if (offset != null && length != null) {
-        return new Selection(offset, length);
-      }
+Selection _parseSelection(String selectionOption) {
+  if(selectionOption == null) return null;
+
+  var units = selectionOption.split(',');
+  if (units.length == 2) {
+    var offset = _toInt(units[0]);
+    var length = _toInt(units[1]);
+    if (offset != null && length != null) {
+      return new Selection(offset, length);
     }
   }
   throw new FormatterException('Selections are specified as integer pairs '
@@ -152,9 +152,9 @@ _formatFile(file) {
   }
 }
 
-_isPatchFile(file) => file.path.endsWith('_patch.dart');
+bool _isPatchFile(file) => file.path.endsWith('_patch.dart');
 
-_isDartFile(file) => dartFileRegExp.hasMatch(path.basename(file.path));
+bool _isDartFile(file) => dartFileRegExp.hasMatch(path.basename(file.path));
 
 _formatStdin(kind) {
   var input = new StringBuffer();
@@ -221,7 +221,7 @@ String _format(src, kind) {
   return formatResult.source;
 }
 
-_toJson(formatResult) =>
+String _toJson(formatResult) =>
     // Actual JSON format TBD
     JSON.encode({'source': formatResult.source,
                  'selection': {