Roll Observatory packages and add a roll script

petitparser/lib/src/debug/profile.dart

-part of debug;
-
-/**
- * Returns a transformed [parser] that when being used measures
- * the activation count and total time of each parser.
- *
- * For example, the snippet
- *
- *     var parser = letter() & word().star();
- *     profile(parser).parse('f1234567890');
- *
- * produces the following output:
- *
- *      1  2006  Instance of 'SequenceParser'
- *      1   697  Instance of 'PossessiveRepeatingParser'[0..*]
- *     11   406  Instance of 'CharacterParser'[letter or digit expected]
- *      1   947  Instance of 'CharacterParser'[letter expected]
- *
- * The first number refers to the number of activations of each parser, and
- * the second number is the microseconds spent in this parser and all its
- * children.
- */
-Parser profile(Parser root, [OutputHandler output = print]) {
-  var count = new Map();
-  var watch = new Map();
-  var parsers = new List();
-  return new ContinuationParser(transformParser(root, (parser) {
-    parsers.add(parser);
-    return new ContinuationParser(parser, (continuation, context) {
-      count[parser]++;
-      watch[parser].start();
-      var result = continuation(context);
-      watch[parser].stop();
-      return result;
-    });
-  }), (continuation, context) {
-    parsers.forEach((parser) {
-      count[parser] = 0;
-      watch[parser] = new Stopwatch();
-    });
-    var result = continuation(context);
-    parsers.forEach((parser) {
-      output('${count[parser]}\t'
-          '${watch[parser].elapsedMicroseconds}\t'
-          '${parser}');
-    });
-    return result;
-  });
-}