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- [/==============================================================================
- Copyright (C) 2001-2015 Joel de Guzman
- Copyright (C) 2001-2011 Hartmut Kaiser
- Distributed under the Boost Software License, Version 1.0. (See accompanying
- file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
- ===============================================================================/]
- [section Number List - stuffing numbers into a std::vector]
- This sample demonstrates a parser for a comma separated list of numbers and
- using a semantic action to collect the numbers into a `std::vector`.
- template <typename Iterator>
- bool parse_numbers(Iterator first, Iterator last, std::vector<double>& v)
- {
- using x3::double_;
- using x3::phrase_parse;
- using x3::_attr;
- using ascii::space;
- auto push_back = [&](auto& ctx){ v.push_back(_attr(ctx)); };
- bool r = phrase_parse(first, last,
- // Begin grammar
- (
- double_[push_back]
- >> *(',' >> double_[push_back])
- )
- ,
- // End grammar
- space);
- if (first != last) // fail if we did not get a full match
- return false;
- return r;
- }
- The full cpp file for this example can be found here:
- [@../../../example/x3/num_list/num_list2.cpp num_list2.cpp]
- This, again, is the same parser as before. This time, instead of summing up the
- numbers, we stuff them in a `std::vector`.
- [&](auto& ctx){ v.push_back(_attr(ctx)); }
- [endsect]
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