dartfmt line length command line option support.

pkg/analyzer/bin/formatter.dart

Index: pkg/analyzer/bin/formatter.dart
===================================================================
--- pkg/analyzer/bin/formatter.dart	(revision 32022)
+++ pkg/analyzer/bin/formatter.dart	(working copy)
@@ -26,6 +26,16 @@
 Selection selection;
 final List<String> paths = [];
 
+
+const HELP_FLAG = 'help';
+const KIND_FLAG = 'kind';
+const MACHINE_FLAG = 'machine';
+const WRITE_FLAG = 'write';
+const SELECTION_FLAG = 'selection';
+const TRANSFORM_FLAG = 'transform';
+const MAX_LINE_FLAG = 'max_line_length';
+
+
 const FOLLOW_LINKS = false;
 
 
@@ -47,12 +57,13 @@
 }
 
 _readOptions(options) {
-  kind = _parseKind(options['kind']);
-  machineFormat = options['machine'];
-  overwriteFileContents = options['write'];
-  selection = _parseSelection(options['selection']);
+  kind = _parseKind(options[KIND_FLAG]);
+  machineFormat = options[MACHINE_FLAG];
+  overwriteFileContents = options[WRITE_FLAG];
+  selection = _parseSelection(options[SELECTION_FLAG]);
   formatterSettings =
-      new FormatterOptions(codeTransforms: options['transform']);
+      new FormatterOptions(codeTransforms: options[TRANSFORM_FLAG],
+          pageWidth: _toInt(options[MAX_LINE_FLAG]));
 }
 
 CodeKind _parseKind(kindOption) {
@@ -142,20 +153,22 @@
 ArgParser _initArgParser() {
   // NOTE: these flags are placeholders only!
   var parser = new ArgParser();
-  parser.addFlag('write', abbr: 'w', negatable: false,
+  parser.addFlag(WRITE_FLAG, abbr: 'w', negatable: false,
       help: 'Write reformatted sources to files (overwriting contents).  '
             'Do not print reformatted sources to standard output.');
-  parser.addOption('kind', abbr: 'k', defaultsTo: 'cu',
+  parser.addFlag(TRANSFORM_FLAG, abbr: 't', negatable: false,
+      help: 'Perform code transformations.');
+  parser.addOption(MAX_LINE_FLAG, abbr: 'l', defaultsTo: '80',

[Brian Wilkerson, 2014/01/27 18:38:42]

Do we want to support an easy way to not wrap lines (as opposed to setting some
ridiculously long line length and hoping it's long enough)?

[pquitslund, 2014/01/27 19:06:03]

Maybe.  I'd rather not add another flag.  Do you think a value like -1 is too
opaque?

[Brian Wilkerson, 2014/01/27 19:12:27]

I agree. Especially since it would then be possible to specify conflicting
options.
Not if you mention it in the help description. (Although "0" would work just as
well and might be easier to parse.)

+      help: 'Wrap lines longer than this length.');
+  parser.addOption(KIND_FLAG, abbr: 'k', defaultsTo: 'cu',
       help: 'Specify source snippet kind ("stmt" or "cu")'
             ' --- [PROVISIONAL API].', hide: true);
-  parser.addFlag('machine', abbr: 'm', negatable: false,
-      help: 'Produce output in a format suitable for parsing.');
-  parser.addOption('selection', abbr: 's',
+  parser.addOption(SELECTION_FLAG, abbr: 's',
       help: 'Specify selection information as an offset,length pair '
             '(e.g., -s "0,4").', hide: true);
-  parser.addFlag('transform', abbr: 't', negatable: true,
-      help: 'Perform code transformations.');
-  parser.addFlag('help', abbr: 'h', negatable: false,
+  parser.addFlag(MACHINE_FLAG, abbr: 'm', negatable: false,
+      help: 'Produce output in a format suitable for parsing.');
+  parser.addFlag(HELP_FLAG, abbr: 'h', negatable: false,
       help: 'Print this usage information.');
   return parser;
 }