[ragel-users] Acting when EOF

[Adrian Thurston]

Hi Inaki,

You can either add another character or set eof = pe to induce the final action. Leaving actions require one char of lookahead.

Adrian
------Original Message------
From: Iñaki Baz Castillo
To: ragel-users at complang.org
ReplyTo: ragel-users at complang.org
Sent: Jan 30, 2009 7:08 AM
Subject: Re: [ragel-users] Acting when EOF

2009/1/27 Iñaki Baz Castillo <ibc at aliax.net>:
> Hi, I've done a simple parser for a SIP URI ("sip:user at domain.org")
> but I can't get the last field ("host"):
>
> --------------------------------------------------------
> %%{
>        machine sip_uri;
>
>        action _tag { mark_tag = p }
>        action protocol { @uri.user = data[mark_tag..p-1].pack('c*') }
>        action user { @uri.protocol = data[mark_tag..p-1].pack('c*') }
>        action host { @uri.host = data[mark_tag..p-1].pack('c*') }
>
>        protocol = ('sip'i|'sips'i) >_tag %protocol ;
>        user = [a-zA-Z0-9]+ >_tag %user ;
>        host = [.a-zA-Z0-9]+ >_tag %host ;
>
>        main := protocol ':' user '@' host ;
> }%%
>
> run_machine "sip:user at domain.org"
> -------------------------------------------------------
>
> The actions "protocol" and "user" are executed, storing the parsed
> data into a Ruby attribute, but the action "host" is not executed. I
> assume this occurs because leaving action (%) doesn't take place but
> EOF action. So I try to use a EOF action:
>
>        host = [.a-zA-Z0-9]+ >_tag %/host ;
>
> But it doesn't work. I can't imagine how to get this "host" field, any
> help please?

I can solve it by adding '\0' and the end of the Ruby String acting as
"run_machine" argument, and also adding the following to the machine
"main":

   main := protocol ':' user '@' host '\0' ;

Not sure, however, if this is the cleaner solution.



-- 
Iñaki Baz Castillo
<ibc at aliax.net>

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