Thanks for quick reply. I have read Jake's camlp4 series carefully, unfortunately it does not cover my case :-(
On Thu, Nov 24, 2011 at 10:47 AM, Gabriel Scherer <gabriel.sche...@gmail.com > wrote: > Camlp4 performs grammar factorizations that make its behavior non > strictly LL(k). > > I never bothered to learn the exact semantics of Camlp4 grammar rules; > they're complex and, I suspect, possibly fragile. If you avoid being > clever with ambiguities, you can get away with the gory details. > > You should have a look at Jake Donham excellent blog series about Camlp4: > > http://ambassadortothecomputers.blogspot.com/2010/05/reading-camlp4-part-6-parsing.html > > 2011/11/24 bob zhang <bobzhang1...@gmail.com>: > > Hi List, > > I have came across a strange behavior of the camlp4 parser, (maybe not > > that weird due to my limited knowledge of the parser) > > The contrived mini-examples as follows : > > module MGram = MakeGram(Lexer) ;; > > EXTEND MGram > > GLOBAL: m_expr ; > > m_expr : > > [[ "foo"; f -> print_endline "first" > > | "foo" ; "bar"; "baz" -> print_endline "second"] > > ]; > > f : [["bar"; "baz" ]]; END;; > > MGram.parse_string m_expr (Loc.mk "<string>") "foo bar baz ";; > > second (** choose the second branch, maybe the token rule has a higher > > priority *) > > > > MGram.Entry.clear m_expr;; > > EXTEND MGram > > GLOBAL: m_expr ; > > m_expr : > > [[ "foo"; f -> print_endline "first" > > | "foo" ; "bar"; "bax" -> print_endline "second"] > > ]; > > f : [["bar"; "baz" ]]; END;; > > - : unit = () > > # MGram.parse_string m_expr (Loc.mk "<string>") "foo bar baz ";; > > first (** here choose the first branch, but the token rule can consume > > one token, I thought this should fail *) > > > > Many Thanks > > > > > > -- > > Caml-list mailing list. Subscription management and archives: > > https://sympa-roc.inria.fr/wws/info/caml-list > > Beginner's list: http://groups.yahoo.com/group/ocaml_beginners > > Bug reports: http://caml.inria.fr/bin/caml-bugs > > > > > -- Best, bob -- Caml-list mailing list. Subscription management and archives: https://sympa-roc.inria.fr/wws/info/caml-list Beginner's list: http://groups.yahoo.com/group/ocaml_beginners Bug reports: http://caml.inria.fr/bin/caml-bugs
