boost::lambda start learning

[yurec]

Hi
I start learning boost.Today I tried to use boost::lambda but failed
to compile very simple example.
2 hours of googling gave nothing.
Can anybody help me?

using namespace boost::lambda;

typedef std::map<int,st d::string_ttype ;
type test;
test[0] = (_T("1"));
test[1] = (_T("2"));
test[2] = (_T("3"));

std::vector<std ::string_ttest_ vector;

std::for_each(t est.begin(),tes t.end(),

test_vector.pus h_back(bind(&ty pe::value_type: :second,_1))
);

---------------------------------------------------------------------------------
: error C2664: 'std::vector<_T y>::push_back' : cannot convert
parameter 1 from 'const boost::lambda:: lambda_functor< T>' to 'const
std::string_t &'

[Victor Bazarov]

Re: boost::lambda start learning

yurec wrote:

I start learning boost.Today I tried to use boost::lambda but failed
to compile very simple example.
2 hours of googling gave nothing.
Can anybody help me?
>
using namespace boost::lambda;
>
typedef std::map<int,st d::string_ttype ;

I've never seen 'std::string_t' , what is is? There is no mention
of 'string_t' in the Standard.

type test;
test[0] = (_T("1"));
test[1] = (_T("2"));
test[2] = (_T("3"));
>
std::vector<std ::string_ttest_ vector;
>
std::for_each(t est.begin(),tes t.end(),
>
test_vector.pus h_back(bind(&ty pe::value_type: :second,_1))
);
>
---------------------------------------------------------------------------------

>error C2664: 'std::vector<_T y>::push_back' : cannot convert

parameter 1 from 'const boost::lambda:: lambda_functor< T>' to 'const
std::string_t &'

V
--
Please remove capital 'A's when replying by e-mail
I do not respond to top-posted replies, please don't ask

[=?iso-8859-1?q?Kirit_S=E6lensminde?=]

Re: boost::lambda start learning

On Oct 30, 10:02 pm, yurec <Yurij.Zha...@m aterialise.kiev .uawrote:

Hi
I start learning boost.Today I tried to use boost::lambda but failed
to compile very simple example.
2 hours of googling gave nothing.
Can anybody help me?
>
using namespace boost::lambda;
>
typedef std::map<int,st d::string_ttype ;
type test;
test[0] = (_T("1"));
test[1] = (_T("2"));
test[2] = (_T("3"));

Microsoft's _T hack doesn't really address any of the important issues
to do with going from narrow characters to wide characters. You're
normally better off just using wide characters if you think you'll
need them and narrow if you won't.

>
std::vector<std ::string_ttest_ vector;
>
std::for_each(t est.begin(),tes t.end(),
>
test_vector.pus h_back(bind(&ty pe::value_type: :second,_1))
);

You need to do a double bind. Although bind you have isn't really to a
function, what you need to do is still function composition so you
need a double bind - the first to bind to type::value_typ e::second and
the second to bind to push_back.

Take a look at this generic composition example: http://www.boostcookbook.com/Recipe:/1234820

---------------------------------------------------------------------------------
: error C2664: 'std::vector<_T y>::push_back' : cannot convert
parameter 1 from 'const boost::lambda:: lambda_functor< T>' to 'const
std::string_t &'

This is because you can't pass the functor you get from bind to
push_back as you're doing. You need to also bind push_back.


K

[Wade Ward]

Re: boost::lambda start learning


"Kirit Sælensminde" <kirit.saelensm inde@gmail.comw rote in message
news:1193801172 .814120.146730@ z9g2000hsf.goog legroups.com...

On Oct 30, 10:02 pm, yurec <Yurij.Zha...@m aterialise.kiev .uawrote:

>Hi
>I start learning boost.Today I tried to use boost::lambda but failed
>to compile very simple example.
>2 hours of googling gave nothing.
>Can anybody help me?
>>
>using namespace boost::lambda;
>>
> typedef std::map<int,st d::string_ttype ;
> type test;
> test[0] = (_T("1"));
> test[1] = (_T("2"));
> test[2] = (_T("3"));

>
Microsoft's _T hack doesn't really address any of the important issues
to do with going from narrow characters to wide characters. You're
normally better off just using wide characters if you think you'll
need them and narrow if you won't.
>

>>
> std::vector<std ::string_ttest_ vector;
>>
> std::for_each(t est.begin(),tes t.end(),
>>
>test_vector.pu sh_back(bind(&t ype::value_type ::second,_1))
> );

>
You need to do a double bind. Although bind you have isn't really to a
function, what you need to do is still function composition so you
need a double bind - the first to bind to type::value_typ e::second and
the second to bind to push_back.
>
Take a look at this generic composition example:

http://www.boostcookbook.com/Recipe:/1234820

>

>---------------------------------------------------------------------------------
>: error C2664: 'std::vector<_T y>::push_back' : cannot convert
>parameter 1 from 'const boost::lambda:: lambda_functor< T>' to 'const
>std::string_ t &'

>
This is because you can't pass the functor you get from bind to
push_back as you're doing. You need to also bind push_back.

so nice to see. work along these lines that isn't mine.

Is it possible that c++ understands what a functor is?

--
wade ward

President
Merrill Jensen Consulting


wade@zaxfuuq.ne t
435 -838-7760

[yurec]

Re: boost::lambda start learning

On 31 , 06:45, "Wade Ward" <zaxf...@invali d.netwrote:

"Kirit Sælensminde" <kirit.saelensm i...@gmail.comw rote in message
>
news:1193801172 .814120.146730@ z9g2000hsf.goog legroups.com...
>

On Oct 30, 10:02 pm, yurec <Yurij.Zha...@m aterialise.kiev .uawrote:

Hi
I start learning boost.Today I tried to use boost::lambda but failed
to compile very simple example.
2 hours of googling gave nothing.
Can anybody help me?

>

using namespace boost::lambda;

>

typedef std::map<int,st d::string_ttype ;
type test;
test[0] = (_T("1"));
test[1] = (_T("2"));
test[2] = (_T("3"));

>

Microsoft's _T hack doesn't really address any of the important issues
to do with going from narrow characters to wide characters. You're
normally better off just using wide characters if you think you'll
need them and narrow if you won't.

>

std::vector<std ::string_ttest_ vector;

>

std::for_each(t est.begin(),tes t.end(),

>

test_vector.pus h_back(bind(&ty pe::value_type: :second,_1))
);

>

You need to do a double bind. Although bind you have isn't really to a
function, what you need to do is still function composition so you
need a double bind - the first to bind to type::value_typ e::second and
the second to bind to push_back.

>

Take a look at this generic composition example:
http://www.boostcookbook.com/Recipe:/1234820

>

---------------------------------------------------------------------------------
: error C2664: 'std::vector<_T y>::push_back' : cannot convert
parameter 1 from 'const boost::lambda:: lambda_functor< T>' to 'const
std::string_t &'

>

This is because you can't pass the functor you get from bind to
push_back as you're doing. You need to also bind push_back.

>
so nice to see. work along these lines that isn't mine.
>
Is it possible that c++ understands what a functor is?
>
--
wade ward
>
President
Merrill Jensen Consulting
>
w...@zaxfuuq.ne t
435 -838-7760

Ok, thanks to everybody, I work with it a little more , understand
better and now everyting is ok.