[ragel-users] nondeterminism problem

[Adrian Thurston]

Define:

colon = ':' @(colon, 1);
else_colon = ':' @(colon, 0);

Then use colon in the named headers and else_colon in the final case.

-Adrian

On 10-11-09 12:07 AM, hongbin kou wrote:
> Now I’m using ragel to build a http parser.
>
> One requirement of the parser is to parse all the http headers, which
> would be used by another module.
>
> For some common headers, the header value would be parsed directly by
> ragel.
>
> For other headers, only mark the header name and value.
>
> Here is my ragel script:
>
> message_header =(
>
>                    ("Content-Length"i ":" LWS* digit+ $on_content_length)
>
>                  | ("Transfer-Encoding"i ":" LWS* ("Chunked"i %
> {request->transfer_encoding = HTTP_TE_CHUNKED;} | any* > start_TE %
> finish_TE))
>
>                  | ("Connection"i ":" LWS* ("Keep-alive"i %
> {request->connection = HTTP_CONNECTION_KEEP_ALIVE;} | "Close"i %
> {request->connection = HTTP_CONNECTION_CLOSE;}))
>
>                  | ("Host"i ":" LWS* field_content >start_host
> %*finish_host* %/break_host)
>
>                  | ("Accept"i ":" LWS* field_content >start_accept %
> finish_accept %/break_accept)
>
>                  | ("Accept-Charset"i ":" LWS* field_content
>  >start_accept_charset % finish_accept_charset %/break_accept_charset)
>
>                  | ("Accept-Encoding"i ":" LWS* field_content
>  >start_accept_encoding % finish_accept_encoding %/break_accept_encoding)
>
>                  | ("Accept-Language"i ":" LWS* field_content
>  >start_accept_language % finish_accept_language %/break_accept_language)
>
>                  | ("User-Agent"i ":" LWS* field_content
>  >start_user_agent % finish_user_agent %/break_user_agent)
>
>                  | ("Referer"i ":" LWS* field_content >start_referer %
> finish_referer %/break_referer)
>
>                  | ("X-Forward-For"i ":" LWS* field_content
>  >start_x_forward_for % finish_x_forward_for %/break_x_forward_for)
>
>                  | ((token) >start_header_name %finish_header_name
> %/break_header_name":" LWS* field_content % *header_end*)
>
>              ) :>CRLF;
>
> Here there is a nondeterminism between token and the common header names.
>
> For example, when a Host header value finished, the header’s action
> finish_host and the “token” action header_end will be triggered.
>
> How can I resolve this kind of problem?
>
>
> Thanks.
>
>
> Hongbin.
>
>
>
>
> _______________________________________________
> ragel-users mailing list
> ragel-users at complang.org
> http://www.complang.org/mailman/listinfo/ragel-users

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