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yap/print.hpp
2016-12-07 20:01:13 -06:00

98 lines
3.0 KiB
C++

#ifndef BOOST_PROTO17_PRINT_HPP_INCLUDED
#define BOOST_PROTO17_PRINT_HPP_INCLUDED
#include "expression_fwd.hpp"
#include <boost/hana/for_each.hpp>
#include <boost/type_index.hpp>
#include <iostream>
namespace boost::proto17 {
namespace detail {
inline std::ostream & print_kind (std::ostream & os, expr_kind kind)
{
switch (kind) {
case expr_kind::plus: return os << "+";
case expr_kind::minus: return os << "-";
// TODO
default: return os << "** ERROR: UNKNOWN OPERATOR! **";
}
}
template <typename T>
auto print_value (std::ostream & os, T const & x) -> decltype(os << x)
{ return os << x; }
inline std::ostream & print_value (std::ostream & os, ...)
{ return os << "<<unprintable-value>>"; }
template <typename T>
std::ostream & print_type (std::ostream & os)
{
os << typeindex::type_id<T>().pretty_name();
if (std::is_const_v<T>)
os << " const";
if (std::is_volatile_v<T>)
os << " volatile";
using no_cv_t = std::remove_cv_t<T>;
if (std::is_lvalue_reference_v<T>)
os << " &";
if (std::is_rvalue_reference_v<T>)
os << " &&";
return os;
}
template <expr_kind Kind, typename T, typename ...Ts>
std::ostream & print_impl (
std::ostream & os,
expression<Kind, T, Ts...> const & expr,
int indent,
char const * indent_str)
{
for (int i = 0; i < indent; ++i) {
os << indent_str;
}
if constexpr (Kind == expr_kind::terminal) {
using namespace hana::literals;
static_assert(sizeof...(Ts) == 0);
os << "term<";
print_type<T>(os);
os << ">[=";
print_value(os, expr.elements[0_c]);
os << "]\n";
} else if constexpr (Kind == expr_kind::placeholder) {
using namespace hana::literals;
static_assert(sizeof...(Ts) == 0);
os << "placeholder<" << (long long)expr.elements[0_c] << ">\n";
} else {
os << "expr<";
print_kind(os, Kind);
os << ">\n";
hana::for_each(expr.elements, [&os, indent, indent_str](auto const & element) {
print_impl(os, element, indent + 1, indent_str);
});
}
return os;
}
}
template <expr_kind Kind, typename ...T>
std::ostream & print (std::ostream & os, expression<Kind, T...> const & expr)
{ return detail::print_impl(os, expr, 0, " "); }
#if defined(BOOST_PROTO17_STREAM_OPERATORS)
template <expr_kind Kind, typename ...T>
std::ostream & operator<< (std::ostream & os, expression<Kind, T...> const & expr)
{ return detail::print_impl(os, expr, 0, " "); }
#endif
}
#endif