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A Reversible Algorithm is a member of a pair of transformation algorithms that iterate over their input sequence(s) in opposite directions. For each reversible algorithm x there exists a counterpart algorithm reverse_x, that exhibits the exact semantics of x except that the elements of its input sequence argument(s) are processed in the reverse order.
In the following table and subsequent specifications, x is a placeholder token for the actual Reversible Algorithm's name, s1,s2,...sn are Forward Sequences, and in is an Inserter.
| Expression | Type | Complexity |
|---|---|---|
| x<s1,s2,...sn, ...>::type | Forward Sequence | Unspecified. |
| x<s1,s2,...sn, ... in>::type | Any type | Unspecified. |
| reverse_x<s1,s2,...sn, ...>::type | Forward Sequence | Unspecified. |
| reverse_x<s1,s2,...sn, ... in>::type | Any type | Unspecified. |
typedef x<s1,s2,...sn,...>::type t;
| Precondition: | s1 is an Extensible Sequence. |
|---|---|
| Semantics: | t is equivalent to
x<
s1,s2,...sn,...
, back_inserter< clear<s1>::type >
>::type
if has_push_back<s1>::value == true and
reverse_x<
s1,s2,...sn,...
, front_inserter< clear<s1>::type >
>::type
otherwise. |
typedef x<s1,s2,...sn,...in>::type t;
| Semantics: | t is the result of an x invocation with arguments s1,s2,... sn,...in. |
|---|
typedef reverse_x<s1,s2,... sn,... >::type t;
| Precondition: | s1 is an Extensible Sequence. |
|---|---|
| Semantics: | t is equivalent to
x<
s1,s2,...sn,...
, front_inserter< clear<s1>::type >
>::type
if has_push_front<s1>::value == true and
reverse_x<
s1,s2,...sn,...
, back_inserter< clear<s1>::type >
>::type
otherwise. |
typedef reverse_x<s1,s2,...sn,... in>::type t;
| Semantics: | t is the result of a reverse_x invocation with arguments s1,s2,...sn,...in. |
|---|
typedef transform< range_c<int,0,10> , plus<_1,int_<7> > , back_inserter< vector0<> > >::type r1; typedef transform< r1, minus<_1,int_<2> > >::type r2; typedef reverse_transform< r2 , minus<_1,5> , front_inserter< vector0<> > >::type r3; BOOST_MPL_ASSERT(( equal<r1, range_c<int,7,17> > )); BOOST_MPL_ASSERT(( equal<r2, range_c<int,5,15> > )); BOOST_MPL_ASSERT(( equal<r3, range_c<int,0,10> > ));