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Simplify tuple formatting

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This commit is contained in:
Victor Zverovich
2021-12-29 08:00:36 -08:00
parent 187e8db1be
commit 9c0c1bcdbd
1 changed files with 10 additions and 26 deletions
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36
include/fmt/ranges.h
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@ -13,22 +13,13 @@
#define FMT_RANGES_H_ #define FMT_RANGES_H_
#include <initializer_list> #include <initializer_list>
#include <tuple>
#include <type_traits> #include <type_traits>
#include "format.h" #include "format.h"
FMT_BEGIN_NAMESPACE FMT_BEGIN_NAMESPACE
template <typename Char, typename Enable = void> struct formatting_tuple {
Char prefix = '(';
Char postfix = ')';
template <typename ParseContext>
FMT_CONSTEXPR auto parse(ParseContext& ctx) -> decltype(ctx.begin()) {
return ctx.begin();
}
};
namespace detail { namespace detail {
template <typename RangeT, typename OutputIterator> template <typename RangeT, typename OutputIterator>
@ -176,7 +167,7 @@ struct is_range_<T, void>
# undef FMT_DECLTYPE_RETURN # undef FMT_DECLTYPE_RETURN
#endif #endif
/// tuple_size and tuple_element check. // tuple_size and tuple_element check.
template <typename T> class is_tuple_like_ { template <typename T> class is_tuple_like_ {
template <typename U> template <typename U>
static auto check(U* p) -> decltype(std::tuple_size<U>::value, int()); static auto check(U* p) -> decltype(std::tuple_size<U>::value, int());
@ -556,37 +547,30 @@ template <typename T> struct is_tuple_like {
template <typename TupleT, typename Char> template <typename TupleT, typename Char>
struct formatter<TupleT, Char, enable_if_t<fmt::is_tuple_like<TupleT>::value>> { struct formatter<TupleT, Char, enable_if_t<fmt::is_tuple_like<TupleT>::value>> {
private: private:
// C++11 generic lambda for format() // C++11 generic lambda for format().
template <typename FormatContext> struct format_each { template <typename FormatContext> struct format_each {
template <typename T> void operator()(const T& v) { template <typename T> void operator()(const T& v) {
if (i > 0) out = detail::write_delimiter(out); if (i > 0) out = detail::write_delimiter(out);
out = detail::write_range_entry<Char>(out, v); out = detail::write_range_entry<Char>(out, v);
++i; ++i;
} }
formatting_tuple<Char>& formatting; int i;
size_t& i; typename FormatContext::iterator& out;
typename std::add_lvalue_reference<
decltype(std::declval<FormatContext>().out())>::type out;
}; };
public: public:
formatting_tuple<Char> formatting;
template <typename ParseContext> template <typename ParseContext>
FMT_CONSTEXPR auto parse(ParseContext& ctx) -> decltype(ctx.begin()) { FMT_CONSTEXPR auto parse(ParseContext& ctx) -> decltype(ctx.begin()) {
return formatting.parse(ctx); return ctx.begin();
} }
template <typename FormatContext = format_context> template <typename FormatContext = format_context>
auto format(const TupleT& values, FormatContext& ctx) -> decltype(ctx.out()) { auto format(const TupleT& values, FormatContext& ctx) -> decltype(ctx.out()) {
auto out = ctx.out(); auto out = ctx.out();
size_t i = 0; *out++ = '(';
detail::for_each(values, format_each<FormatContext>{0, out});
detail::copy(formatting.prefix, out); *out++ = ')';
detail::for_each(values, format_each<FormatContext>{formatting, i, out}); return out;
detail::copy(formatting.postfix, out);
return ctx.out();
} }
}; };