Synopsis

template<
      typename Sequence
    , typename Op
    , typename In = unspecified
    >
struct transform
{
    typedef unspecified type;
};

template<
      typename Seq1
    , typename Seq2
    , typename BinaryOp
    , typename In = unspecified
    >
struct transform
{
    typedef unspecified type;
};

Description

transform is an overloaded name:

• transform<Sequence,Op> returns a transformed copy of the original sequence produced by applying an unary transformation Op to every element in the [begin<Sequence>::type, end<Sequence>::type) range.
• transform<Seq1,Seq2,BinaryOp> returns a new sequence produced by applying a binary transformation BinaryOp to a pair of elements (e₁, e2₁) from the corresponding [begin<Seq1>::type, end<Seq1>::type) and [begin<Seq2>::type, end<Seq2>::type) ranges.

[Note: This wording applies to a no-inserter version(s) of the algorithm. See the Expression semantics subsection for a precise specification of the algorithm's details in all cases — end note]

Header

#include <boost/mpl/transform.hpp>

Model of

Reversible Algorithm

Parameters

Expression semantics

The semantics of an expression are defined only where they differ from, or are not defined in Reversible Algorithm.

For any Forward Sequences s, s1 and s2, Lambda Expressions op and op2, and an Inserter in:

typedef transform<s,op,in>::type r;

typedef lambda<op>::type f;
typedef lambda<in::operation>::type in_op;

typedef fold<
      s
    , in::state
    , bind< in_op, _1, bind<f, _2> >
    >::type r;

typedef transform<s1,s2,op,in>::type r;

typedef lambda<op2>::type f;
typedef lambda<in::operation>::type in_op;

typedef fold<
      pair_view<s1,s2>
    , in::state
    , bind<
          in_op
        , _1
        , bind<f, bind<first<>,_2>, bind<second<>,_2> >
        >
    >::type r;

Complexity

Linear. Exactly size<s>::value / size<s1>::value applications of op / op2 and in::operation.

Example

typedef vector<char,short,int,long,float,double> types;
typedef vector<char*,short*,int*,long*,float*,double*> pointers;
typedef transform< types,boost::add_pointer<_1> >::type result;

BOOST_MPL_ASSERT(( equal<result,pointers> ));

See also

Transformation Algorithms, Reversible Algorithm, reverse_transform, copy, replace_if