[ragel-users] Re: two state machines

[massimiliano cialdi]

On Sat, Jun 7, 2008 at 7:39 AM, mitchell <mforal.n... at gmail.com> wrote:
>
> Hi,
>
> Untested, but it's an idea I had:

I tried the same thing, and I have some doubt

here is my source (is only a simplified example of my really need):
----------------------------8<-------------------------------------
#include <string.h>
#include <stdio.h>
%%{
	# test for dua FSM definition
	# I want to match a pattern like A"12345FFF01"B ( or A"99FFFFF99"B or
A"321FFFFF14"B )
	# once take the substring between quotes I want to pass it to FSM1
that match exacly
	
	machine test1;
	
	action copycar
	{
		printf("%c\n",fc);
		// populating FN
		*fn = fc;
		fn++;
	}
	
	action error
	{
		printf("error %d, %c\n",cs,fc);
		fbreak;
	}
	
	action endpt1
	{
		printf("OK\n%s\n", FN);
		// setting new buffer margin for FSM1. It must operate on FN
		p = FN;
		pe = p + strlen(p) + 1;
		fgoto FSM1;
	}
		
	action endsubstr
	{
		// placing null termination to substring in FN
		*fn = '\0';
	}

	action endpt2
	{
		// substring matches
		printf("OK pt2\n");
	}
	
	FSM1 := '12345FFF' @!error @endpt2 >~{printf("*** %d %c %s ***\n",cs,
fc, fpc);};
	
	main := ( 'A"' ( digit{2} (digit | 'F'){3} 'F'{3} ) $copycar
@endsubstr digit{2}  '"B' ) @!error @endpt1 ;
	
}%%

%% write data;


void parse(char *buf)
{
	int cs;
	char *eof = 0;
	char *p = buf;
	char *pe = p + strlen(p) + 1;
	
	char FN[16];
	char *fn;
	
	// FN is the container fo the substring
	fn = FN;
	%% write init;
	%% write exec;
}

int main( int argc, char **argv )
{
	if ( argc > 1 ) {
		parse(argv[1]);
	}
	return 0;
}

----------------------------8<-------------------------------------

if you try to execute it fails:

test A\"12345FFF01\"B
1
2
3
4
5
F
F
F
OK
12345FFF
*** 15 1 12345FFF ***
error 0, 2

but the string exactly match the pattern (as can be seen in line "***
15 1 12345FFF ***")

so now try to change the pattern of FSM1 as follow (we delete '1'):
	FSM1 := '2345FFF' @!error @endpt2 >~{printf("*** %d %c %s ***\n",cs,
fc, fpc);};

and retry to execute:

test A\"12345FFF01\"B
1
2
3
4
5
F
F
F
OK
12345FFF
*** 15 1 12345FFF ***
OK pt2

now it report the string matching but we had changed the pattern.
It seems that it skip the first character after fgoto.

so I tried another way.
lets use originale FSM1 definition (pattern '12345FFF'), but change
action endpt1 to add an fhold statement as follow:

	action endpt1
	{
		printf("OK\n%s\n", FN);
		// setting new buffer margin for FSM1. It must operate on FN
		p = FN;
		pe = p + strlen(p) + 1;
		// fhold is translated in C as p--;
		fhold;		
		fgoto FSM1;
	}

and let execute:

test A\"12345FFF01\"B
1
2
3
4
5
F
F
F
OK
12345FFF
*** 15   ***
OK pt2

it seems to work, but action to-state start of FSM1 fails, it cannot
print neither fc character nor pfc string...

is this the right way to do this?

thanks
-- 
Et nunc, auxilium solis, vincam!
Oppugnatio solaris!
VIS!

Massimiliano Cialdi
cia... at gmail.com
massimiliano.cia... at powersoft.it