Add IStreamable helper.

IOStreams/IStreamable.h

@@ -0,0 +1,60 @@
+static_assert( __cplusplus > 2020'00 );
+
+#pragma once
+
+#include <Alepha/Alepha.h>
+
+#include <istream>
+
+#include <Alepha/Capabilities.h>
+#include <Alepha/template_for_each.h>
+#include <Alepha/string_algorithms.h>
+#include <Alepha/Concepts.h>
+
+#include <Alepha/Reflection/tuplizeAggregate.h>
+
+namespace Alepha::Hydrogen::IOStreams  ::detail::  istreamable_module
+{
+	inline namespace exports
+	{
+		struct IStreamable {};
+	}
+
+	template< typename T >
+	concept IStreamableAggregate= Aggregate< T > and Capability< T, IStreamable >;
+
+
+	std::istream &
+	operator >> ( std::istream &is, IStreamableAggregate auto &istreamable )
+	{
+		std::string line;
+		std::getline( is, line );
+		const auto commentChar= line.find( "#" );
+		if( commentChar != std::string::npos ) line= line.substr( line.find( "#" ) );
+
+		const auto tokens= split( line, '\t' );
+
+		auto decomposed= Alepha::Reflection::tuplizeAggregate( istreamable );
+
+		if( tokens.size() != std::tuple_size_v< std::decay_t< decltype( decomposed ) > > )
+		{
+			throw 0;
+		}
+
+		int index= 0;
+		// TODO: Consider the lens system here... but the basic use case seems to be for
+		// aggregates, so we'll go with this simple case for now...
+		tuple_for_each( decomposed ) <=[&]( auto &element )
+		{
+			std::istringstream iss{ tokens.at( index++ ) };
+			iss >> element;
+		};
+
+		return is;
+	}
+}
+
+namespace Alepha::Hydrogen::IOStreams::inline exports::inline istreamable_module
+{
+	using namespace detail::istreamable_module::exports;
+}