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< title > BOOST_PP_LIST_TRANSFORM</ title >
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The < b > BOOST_PP_LIST_TRANSFORM</ b > macro transforms each element in a < i > list</ i > according to a supplied transformation.
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< h4 > Usage</ h4 >
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< b > BOOST_PP_LIST_TRANSFORM</ b > (< i > op</ i > , < i > data</ i > , < i > list</ i > )
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< h4 > Arguments</ h4 >
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< dt > op</ dt >
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A ternary predicate of the form < i > op</ i > (< i > d</ i > , < i > data</ i > , < i > elem</ i > ).
This transformation is expanded by < b > BOOST_PP_LIST_TRANSFORM</ b > for each element in < i > list</ i > with the next available < b > BOOST_PP_WHILE</ b > iteration,
the auxiliary < i > data</ i > , and the current element in < i > list</ i > .
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< dt > data</ dt >
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Auxiliary data passed to < i > pred</ i > .
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< dt > list</ dt >
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The < i > list</ i > to be transformed.
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< h4 > Remarks</ h4 >
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This macro expands < i > op</ i > for each element in < i > list</ i > .
It builds a new < i > list</ i > out of the results of each call.
If, for example, < i > list</ i > is (< i > a</ i > , (< i > b</ i > , (< i > c</ i > , < b > BOOST_PP_NIL</ b > ))),
this macro expands to...
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(< i > op</ i > (< i > d</ i > , < i > data</ i > , < i > a</ i > ), (< i > op</ i > (< i > d</ i > , < i > data</ i > , < i > b</ i > ), (< i > op</ i > (< i > d</ i > , < i > data</ i > , < i > c</ i > ), < b > BOOST_PP_NIL</ b > )))
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Previously, this macro could not be used inside < b > BOOST_PP_WHILE</ b > .
There is no longer any such restriction.
It is more efficient, however, to use < b > BOOST_PP_LIST_TRANSFORM_D</ b > in such a situation.
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< h4 > See Also</ h4 >
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< li >< a href = "list_transform_d.html" > BOOST_PP_LIST_TRANSFORM_D</ a ></ li >
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< h4 > Requirements</ h4 >
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< b > Header:</ b > < a href = "../headers/list/transform.html" > < boost/preprocessor/list/transform.hpp> </ a >
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< h4 > Sample Code</ h4 >
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#include < < a href = "../headers/arithmetic/dec.html" > boost/preprocessor/arithmetic/dec.hpp</ a > >
#include < < a href = "../headers/list/transform.html" > boost/preprocessor/list/transform.hpp</ a > >
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#define LIST (1, (3, (2, (5, < a href = "nil.html" > BOOST_PP_NIL</ a > ))))
#define OP(d, data, elem) < a href = "dec.html" > BOOST_PP_DEC</ a > (elem)
< a href = "list_transform.html" > BOOST_PP_LIST_TRANSFORM</ a > (OP, 3, LIST)
// expands to (0, (2, (1, (4, < a href = "nil.html" > BOOST_PP_NIL</ a > ))))
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< i > © Copyright < a href = "http://www.housemarque.com" target = "_top" > Housemarque Oy</ a > 2002</ i >
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</ br >< i > © Copyright Paul Mensonides 2002</ i >
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< p >< small > Distributed under the Boost Software License, Version 1.0. (See
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accompanying file < a href = "../../../../LICENSE_1_0.txt" > LICENSE_1_0.txt</ a > or
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copy at < a href =
"http://www.boost.org/LICENSE_1_0.txt" > www.boost.org/LICENSE_1_0.txt</ a > )</ small ></ p >
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