Re: [boost] Using Bind & Lambda

From: Hansi (hansipet_at_[hidden])
Date: 2008-06-10 09:46:38

When should be used boost/lamda/bind.hpp? Is there somewhere a 
documentation which compares the 2 implementations?

Best regards
Hansjörg

Steven Watanabe schrieb:
> AMDG
> 
> Robert Jones wrote:
>> First - is "boost/lambda/bind.hpp" equivalent to "boost/bind.hpp"? 
>> Should it
>> ever be necessary to include both?
>>   
> 
> Bind and Lambda are separate.  If you are using Lambda you need to use
> boost/lambda/bind.hpp which contains boost::lambda::bind.
> 
>> Second - Is it true that a lambda function is syntactically and 
>> semantically the
>> same as a bind finction, eg
>>
>> Given:-  int foo( int i ) { return i + 3; }
>>
>> Are these two expressions the same?
>> bind( &foo, _1 );
>> _1 + 3;
>>   
> 
> They should behave the same, unless this is
> a boost::bind and you want to do further composition.
> 
>> Finally (for now!) - why is this wrong?
>>
>> struct A { string identity( string ) const; } a;
>>
>> vector<string> v;
>> for_each( v.begin(), v.end(), cout << bind( &A::identity, a, _1 ) << 
>> '\n' );
>>
>> which is intended to output the return value of A::identity() for each
>> element of v,
>> separated by newlines.
>>   
> 
> It will only work if you using boost::lambda::bind, not boost::bind.
> 
> In Christ,
> Steven Watanabe
> 
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