[ragel-users] Re: Help with extracting a list of numbers

Adrian Thurston thurs... at cs.queensu.ca
Wed Mar 26 02:17:17 UTC 2008


The pe variable should be set to one past the last character. Hope that
clears things up.

Cheers,
 Adrian

Manoj Rajagopalan wrote:
> Hi Adrian
> 
>     The detection works only when I enter a space at the end. And yes, 
> the terminating 0 is being sent. Hope this isn't a bug. Maybe I'm 
> missing something really simple.
> 
>     I'm using Ragel 6.0 on Fedora 8.
> 
>     BTW, I'm attaching a small C++ program if anyone would like to run it.
> 
>     In the program, it prints out the ending character (*pe) and 
> confirms that it is '\0'. Should 'pe' point to the last char or to one 
> past it, i.e., is the character range [p,pe] or [p, pe) ?
> 
>     In one place in the manual I see p+strlen(buf) (fig 5.1, pg 36) 
> whereas in another I see p+strlen(buf)+1 (pg 6)
> 
> 
> -- Manoj
> 
> 
> Adrian Thurston wrote:
>> Hi Manoj,
>>
>> Are you sure the null is being sent to the parser? If it is then
>> printNumber should be executed on the last character.
>>
>> Adrian
>>
>> Manoj Rajagopalan wrote:
>>> Hi all,
>>>
>>>    I'm trying to write a pattern to extract a list of numbers following 
>>> the keyword bond and I'm not able to figure out why my pattern below 
>>> always skips the last number
>>>
>>>    My input is of the form:
>>>
>>>    bond <number> <number> ...
>>>
>>> %%{
>>>      machine bond_parser;
>>>
>>>      whole_number = digit+    >to{intVal=0;}   ${intVal = intVal*10 + 
>>> (fc-'0');}    ;
>>>
>>>      main :=
>>>          space* 'bond'
>>>          (space+ whole_number %printNumber)+
>>>          space* 0;
>>> }%%
>>>
>>> where printNumber is an action to print the number just updated into the 
>>> integer variable intVal.
>>>
>>> The 0 at the end of the pattern is the NULL character that cin.getline() 
>>> adds when reading upto the newline character from the console.
>>>
>>> I realize this may be due to the leaving action for the last number that 
>>> never gets called but could someone tell me a way around this?
>>>
>>> Thanks,
>>> Manoj
>>>
> 
> > 



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