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The MPL Reference Manual: erase
Front Page / Sequences / Intrinsic Metafunctions / erase

erase

Synopsis

template<
      typename Sequence
    , typename First
    , typename Last = unspecified
    >
struct erase
{
    typedef unspecified type;
};

Description

erase performs a removal of one or more adjacent elements in the sequence starting from an arbitrary position.

Parameters

Parameter Requirement Description
Sequence Extensible Sequence or Extensible Associative Sequence A sequence to erase from.
First Forward Iterator An iterator to the beginning of the range to be erased.
Last Forward Iterator An iterator past-the-end of the range to be erased.

Expression semantics

For any Extensible Sequence s, and iterators pos, first and last into s:

typedef erase::type r; 
Return type:Extensible Sequence.
Precondition:[first,last) is a valid range in s.
Semantics:r is a new sequence, concept-identical to s, of the following elements: [begin::type, pos), [last, end::type).
Postcondition:

The relative order of the elements in r is the same as in s;

size::value == size::value - distance::value
typedef erase::type r;
Return type:Extensible Sequence.
Precondition:pos is a dereferenceable iterator in s.
Semantics:

Equivalent to

typedef erase< s,pos,next::type >::type r;

For any Extensible Associative Sequence s, and iterator pos into s:

typedef erase::type r;
Return type:Extensible Sequence.
Precondition:pos is a dereferenceable iterator to s.
Semantics:Erases the element at a specific position pos; equivalent to erase_key deref::type >::type.
Postcondition:size::value == size::value - 1.

Complexity

Sequence archetype Complexity (the range form)
Extensible Associative Sequence Amortized constant time.
Extensible Sequence Quadratic in the worst case, linear at best.

Example

typedef vector_c values;
typedef find< values, integral_c >::type pos;
typedef erase::type result;

BOOST_MPL_ASSERT_RELATION( size::value, ==, 7 );

typedef findintegral_c >::type iter;
BOOST_MPL_ASSERT(( is_same< iter, end::type > ));