54 lines
1.7 KiB
C++
54 lines
1.7 KiB
C++
#ifndef EOLIAN_CXX_ALTERNATIVE_HH
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#define EOLIAN_CXX_ALTERNATIVE_HH
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#include "grammar/generator.hpp"
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#include "grammar/meta.hpp"
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namespace efl { namespace eolian { namespace grammar {
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template <typename L, typename R>
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struct alternative_generator
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{
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template <typename OutputIterator, typename...Args, typename Context>
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bool generate(OutputIterator /*sink*/, eina::variant<Args...> const& /*attribute*/, Context const& /*context*/) const
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{
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// return grammar::alternative_sequence(left, right, sink, attribute);
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return false;
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}
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template <typename OutputIterator, typename Attribute, typename...Args, typename Context>
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bool generate(OutputIterator sink, Attribute const& attribute, Context const& context) const
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{
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if(!attributes::generate(as_generator(left), sink, attribute, context))
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return attributes::generate(as_generator(right), sink, attribute, context);
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else
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return true;
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}
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L left;
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R right;
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};
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template <typename L, typename R>
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struct is_eager_generator<alternative_generator<L, R> > : std::true_type {};
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template <typename L, typename R>
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struct is_generator<alternative_generator<L, R> > : std::true_type {};
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namespace type_traits {
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template <typename L, typename R>
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struct attributes_needed<alternative_generator<L, R> > : std::integral_constant
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<int, meta::max<attributes_needed<L>::value, attributes_needed<R>::value>::value> {};
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template <typename L, typename R>
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struct accepts_tuple<alternative_generator<L, R> > : std::true_type {};
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}
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template <typename L, typename R>
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typename std::enable_if<grammar::is_generator<L>::value && grammar::is_generator<R>::value, alternative_generator<L, R>>::type
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operator|(L l, R r)
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{
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return alternative_generator<L, R>{l, r};
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}
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} } }
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#endif
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