66 lines
1.9 KiB
C++
66 lines
1.9 KiB
C++
// Copyright Antony Polukhin, 2013-2019.
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// Distributed under the Boost Software License, Version 1.0.
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// (See the accompanying file LICENSE_1_0.txt
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// or a copy at <http://www.boost.org/LICENSE_1_0.txt>.)
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#include <boost/config.hpp>
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#ifdef BOOST_MSVC
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# pragma warning(disable: 4512) // generic_stringize.cpp(37) : warning C4512: 'stringize_functor' : assignment operator could not be generated
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#endif
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//[lexical_cast_stringize
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/*`
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In this example we'll make a `stringize` method that accepts a sequence, converts
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each element of the sequence into string and appends that string to the result.
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Example is based on the example from the [@http://www.packtpub.com/boost-cplusplus-application-development-cookbook/book Boost C++ Application Development Cookbook]
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by Antony Polukhin, ISBN 9781849514880.
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Step 1: Making a functor that converts any type to a string and remembers result:
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*/
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#include <boost/lexical_cast.hpp>
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struct stringize_functor {
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private:
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std::string& result;
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public:
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explicit stringize_functor(std::string& res)
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: result(res)
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{}
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template <class T>
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void operator()(const T& v) const {
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result += boost::lexical_cast<std::string>(v);
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}
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};
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//` Step 2: Applying `stringize_functor` to each element in sequence:
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#include <boost/fusion/include/for_each.hpp>
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template <class Sequence>
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std::string stringize(const Sequence& seq) {
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std::string result;
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boost::fusion::for_each(seq, stringize_functor(result));
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return result;
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}
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//` Step 3: Using the `stringize` with different types:
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#include <cassert>
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#include <boost/fusion/adapted/boost_tuple.hpp>
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#include <boost/fusion/adapted/std_pair.hpp>
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int main() {
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boost::tuple<char, int, char, int> decim('-', 10, 'e', 5);
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assert(stringize(decim) == "-10e5");
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std::pair<int, std::string> value_and_type(270, "Kelvin");
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assert(stringize(value_and_type) == "270Kelvin");
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}
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//] [/lexical_cast_stringize]
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