Roll Observatory packages and add a roll script

packages/petitparser/lib/src/json/grammar.dart

-part of json;
+part of petitparser.json;
 
-/**
- * JSON grammar.
- */
+/// JSON grammar.
 class JsonGrammar extends GrammarParser {
   JsonGrammar() : super(const JsonGrammarDefinition());
 }
 
-/**
- * JSON grammar definition.
- */
+/// JSON grammar definition.
 class JsonGrammarDefinition extends GrammarDefinition {
   const JsonGrammarDefinition();
 
   start() => ref(value).end();
   token(p) => p.flatten().trim();
 
   array() => ref(token, char('['))
       & ref(elements).optional()
       & ref(token, char(']'));
   elements() => ref(value).separatedBy(ref(token, char(',')), includeSeparators: false);
@@ skipping 13 matching lines @@
       | ref(nullToken);
 
   trueToken() => ref(token, string('true'));
   falseToken() => ref(token, string('false'));
   nullToken() => ref(token, string('null'));
   stringToken() => ref(token, ref(stringPrimitive));
   numberToken() => ref(token, ref(numberPrimitive));
 
   characterPrimitive() => ref(characterNormal)
       | ref(characterEscape)
-      | ref(characterOctal);
+      | ref(characterUnicode);
   characterNormal() => pattern('^"\\');
   characterEscape() => char('\\')
-      & pattern(new List.from(JSON_ESCAPE_CHARS.keys).join());
-  characterOctal() => string('\\u').seq(pattern("0-9A-Fa-f").times(4).flatten());
+      & pattern(new List.from(jsonEscapeChars.keys).join());
+  characterUnicode() => string('\\u')
+      & pattern("0-9A-Fa-f").times(4);
   numberPrimitive() => char('-').optional()
       & char('0').or(digit().plus())
       & char('.').seq(digit().plus()).optional()
       & pattern('eE').seq(pattern('-+').optional()).seq(digit().plus()).optional();
   stringPrimitive() => char('"')
       & ref(characterPrimitive).star()
       & char('"');
 
 }
 
-const JSON_ESCAPE_CHARS = const {
+const jsonEscapeChars = const {
   '\\': '\\',
   '/': '/',
   '"': '"',
   'b': '\b',
   'f': '\f',
   'n': '\n',
   'r': '\r',
   't': '\t'
 };