Re: [Boost-users] [spirit] real_p fails on negative exponent

Subject: Re: [Boost-users] [spirit] real_p fails on negative exponent
From: Joel de Guzman (joel_at_[hidden])
Date: 2008-12-08 18:55:29

Jan Boehme wrote:
> Hi Joel,
> 
> On Mon, Dec 8, 2008 at 2:07 PM, Joel de Guzman wrote:
>> Jan Boehme wrote:
>>> Hi,
>>>
>>> on my system (RHEL3, libc 2.3.2, gcc 3.2.3, Intel 10.1 which is used to compile and link) real_p fails to parse real numbers like 1.0E-001 and it is most likely the negative exponent as 1.0E001 works as expected.
>>> Our investigations brought us to numerics.hpp line 162 where the int parser which is used by real_p is declared as 'int_parser<T, 10, 1, -1>' with T=double. I don't see the reason for this yet and
>>> the 'out of the box' int parser 'int_p' itself is declared using 'int_parser<int>'.
>>>
>>> Here my questions:
>>> Do I have to expect any problems using int instead double for the real_p exp_n parser?
>>> Is this a kind of a mistake as even int_p is declared using 'int'?
>> Please post a minimal test case. I'd venture a guess that the problem
>> is elsewhere. We do have real_p tests with negative exponents. And
>> all is fine, as expected. I did test your case and it works fine:
>>
>> added this in numeric_tests.cpp:
>>
>>    BOOST_TEST(parse("1.0E-001", real_p).full); //  Good.
> 
> please have a look on my system specs. Maybe I should say that I haven't
> any problems using a modern c++ compiler like gcc 4.2.4 plus intel 10.1.
> 
> You did provide a minimal test case yourself: this test runs fail on my
> system using boost 1.37 and only my 'workaround' let this rule run
> sucessfully on this machine. It consumes all chars including 'E' and
> then '-' doesn't match. Did you try it on a gcc3.2.x too?

I've been using 3.2 until last month. All of Spirit's tests are running
fine. I'll take another look.

BTW, int_parser<double> is perfectly fine.

Regards,
-- 
Joel de Guzman
http://www.boostpro.com
http://spirit.sf.net