There's no way to change the final-state property of a state. It's
decided at compile time.
The fgoto final won't work because you're jumping out of the scanner and
it's the scanner actions that you want.
-Adrian
On 10-06-29 06:52 AM, Brian Maher wrote:
On Mon, Jun 28, 2010 at 10:21 AM, Adrian Thurston wrote:
Just to be certain, you'd like a token at the end of the input to match even
if it is not in a final state?
Yes. Or to put it another way: I want to make eof be a valid final
state kind of like what the $ in perl compatible regular expressions
mean.
If that's the case, I'm sorry I don't have an elegant solution for you. A
state is either final or not, and what you need is to make all states final
when at the end of the input.
Is there a way to say "make this state final when at the end of the
input"? `fgoto final;` was my attempt at doing this, but it didn't
work ;-).
Thanks for your help!
Cheers,
-Brian
On 10-06-27 06:46 AM, Brian Maher wrote:
Hello Ragel Users,
First, I just want to say that Ragel is an awesome tool, thank you
Adrian for sharing this tool with the open source community!
Recently I've been trying to write a grammar for which individual
tokens may be pre-maturely terminated by EOF. I came up with the
following rather hacky solution below (emit the same action as though
the token was "recognized", then fbreak so that only one token is
guaranteed to be "seen"). The things that I don't like with this
solution are that:
* I'm not keen on having to redundantly call the token's action in
two places since a maintainer later on may forget to update one of the
places where $eof(token_action) is done.
* te is not updated (although this isn't a big deal since I can just
use p instead of relying on te, and if I really wanted to make a fuss
about this I could always add $eof{te=p;}).
One idea I had was to $eof{fgoto final;}, but that doesn't work since
the "final" label is only defined within the context of state charts
and can't be used as a "normal label".
--------------example.rl
#include<stdio.h>
%% machine t;
%% write data;
#define INPUT "abcd"
int main() {
char *ts, *te;
int cs, act, i;
char *input = INPUT;
char *p = input;
char *pe = input + (sizeof(INPUT) - 1);
char *eof = pe;
fprintf(stderr, "Input[");
fwrite(p, 1, pe-p, stderr);
fprintf(stderr, "]\n");
%%{
write init;
action text {
fprintf(stderr, "Text [%c]\n", *p);
}
action token {
fprintf(stderr, "Token[");
fwrite(ts, 1, p-ts, stderr);
fprintf(stderr, "]\n");
}
Token = "abc" "def" $eof(token) $eof{fbreak;};
main := |*
Token => token;
any => text;
*|;
write exec;
}%%
fprintf(stderr, "end\n");
return 0;
}
--------------/example.rl
Thanks!
-Brian
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--
Brian Maher>> Glory to God<<
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