Fix compile time formatters for use with 0 argumentsHEADmaster

1 files changed, 28 insertions, 25 deletions

diff --git a/include/cxxformat/core.hpp b/include/cxxformat/core.hpp
index 662f4f8..43b3c41 100644
--- a/include/cxxformat/core.hpp
+++ b/include/cxxformat/core.hpp
@@ -486,33 +486,36 @@ namespace format {
 				const auto out = make_output(std::forward<Output>(output));
 				const auto format_arg = [&args..., &out]<format_specifier spec>(holder<spec>) -> decltype(auto)
 				{
-					optional_int<std::size_t> minWidth = spec.minWidth;
-					if constexpr (spec.flags.widthAsArg)
+					if constexpr (sizeof...(Args) > 0)
 					{
-						using Arg = std::decay_t<nth_type<*spec.minWidth, Args...>>;
-						static_assert(std::unsigned_integral<Arg>, "Width argument must be an unsigned integral");
-						static_assert(sizeof(Arg) <= sizeof(std::size_t), "Width argument type must be at most as big as std::size_t");
-						minWidth = nth_argument<*spec.minWidth>(std::forward<Args>(args)...);
+						optional_int<std::size_t> minWidth = spec.minWidth;
+						if constexpr (spec.flags.widthAsArg)
+						{
+							using Arg = std::decay_t<nth_type<*spec.minWidth, Args...>>;
+							static_assert(std::unsigned_integral<Arg>, "Width argument must be an unsigned integral");
+							static_assert(sizeof(Arg) <= sizeof(std::size_t), "Width argument type must be at most as big as std::size_t");
+							minWidth = nth_argument<*spec.minWidth>(std::forward<Args>(args)...);
+						}
+						optional_int<std::size_t> precision = spec.precision;
+						if constexpr (spec.flags.precisionAsArg)
+						{
+							using Arg = std::decay_t<nth_type<*spec.precision, Args...>>;
+							static_assert(std::unsigned_integral<Arg>, "Precision argument must be an unsigned integral");
+							static_assert(sizeof(Arg) <= sizeof(std::size_t), "Precision argument type must be at most as big as std::size_t");
+							precision = nth_argument<*spec.precision>(std::forward<Args>(args)...);
+						}
+
+						using Arg = nth_type<spec.argIndex, Args...>;
+						Arg&& arg = nth_argument<spec.argIndex>(std::forward<Args>(args)...);
+						using formatter = formatter_with_fallback<std::decay_t<Arg>>;
+
+						[]() consteval {
+							// throws on error
+							formatter::conversionSupported(spec);
+						}();
+
+						return formatter::format(out, std::forward<Arg>(arg), spec, minWidth, precision);
 					}
-					optional_int<std::size_t> precision = spec.precision;
-					if constexpr (spec.flags.precisionAsArg)
-					{
-						using Arg = std::decay_t<nth_type<*spec.precision, Args...>>;
-						static_assert(std::unsigned_integral<Arg>, "Precision argument must be an unsigned integral");
-						static_assert(sizeof(Arg) <= sizeof(std::size_t), "Precision argument type must be at most as big as std::size_t");
-						precision = nth_argument<*spec.precision>(std::forward<Args>(args)...);
-					}
-
-					using Arg = nth_type<spec.argIndex, Args...>;
-					Arg&& arg = nth_argument<spec.argIndex>(std::forward<Args>(args)...);
-					using formatter = formatter_with_fallback<std::decay_t<Arg>>;
-
-					[]() consteval {
-						// throws on error
-						formatter::conversionSupported(spec);
-					}();
-
-					return formatter::format(out, std::forward<Arg>(arg), spec, minWidth, precision);
 				};
 
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