Hi, As I wrote in my previous e-mail, I am trying to write the Java grammar for PetitParser. I am following "The Java Language Specification, Third Edition", which is the last available book written by Sun with the specification for the whole Java language [1]. It covers Java 1.5. The project, PetitJava, is on SqueakSource [2]. I've just "finished" to implement the literals [3] and I am trying it with some tests. I find something strange, thus probably there is something in PetitParser that I don't get. As an example, among the primitives in PPJavaGrammar you find: <snips> PPJavaGrammar>>octalEscape ^ $\ asParser , ( octalDigit / (octalDigit , octalDigit) / (zeroToThree , octalDigit , octalDigit) ) PPJavaGrammar>>octalDigit ^PPPredicateObjectParser anyOf: '01234567' PPJavaGrammar>>zeroToThree ^PPPredicateObjectParser anyOf: '0123' </snips> I take some one of the failing tests as an example: <snips> PPJavaGrammarTest>>testOctalEscape1 self parse: '\0' rule: #octalEscape PPJavaGrammarTest>>testOctalEscape2 self parse: '\00' rule: #octalEscape PPJavaGrammarTest>>testOctalEscape3 self parse: '\000' rule: #octalEscape </snips> While the first test passes as I expected, the second and the third ones do not. However, they should be recognized as: $\ , octalDigit , octalDigit and $\ , zeroToThree, octalDigit , octalDigit as stated in the "octalEscape" implementation. Is there something wrong with my implementation, or didn't I understand correctly the '/' operator? Thank you, Alberto [1] http://java.sun.com/docs/books/jls/third_edition/html/j3TOC.html [2] http://www.squeaksource.com/PetitJava.html [3] http://java.sun.com/docs/books/jls/third_edition/html/lexical.html#3.10