Refactoring.

VM now aims to only wrap Wren's c functions as closely as
possible. All the fun stuff should be put into vm_fun.hpp.

src/wren/vm_fun.hpp

@@ -0,0 +1,86 @@
+#pragma once
+
+#include "vm.hpp"
+#include <string>
+#include <string_view>
+#include <vector>
+
+namespace wren {
+	typedef std::tuple<const char*, const char*> ModuleAndName;
+
+	namespace detail {
+#if __cpp_concepts >= 201907
+		template <typename T>
+		concept ConstCharTuple = requires {
+			std::same_as<std::remove_cv_t<T>, Handle> or
+			std::same_as<std::remove_cv_t<T>, ModuleAndName>;
+		};
+#endif
+	} //namespace detail
+
+#if __cpp_concepts >= 201907
+	template <typename... Outs, detail::ConstCharTuple... Params>
+#else
+	template <typename... Outs, typename... Params>
+#endif
+	std::tuple<Outs...> variables(VM& vm, Params&&... modules_names);
+	void interpret (VM& vm, const std::string& module_name, const std::string& script);
+	void set (VM& vm, int slot_num, const std::string& value);
+	void set (VM& vm, int slot_num, std::string_view value);
+	void set (VM& vm, int slot_num, const std::vector<char>& value);
+	void set (VM& vm, int slot_num, const char* beg, const char* end);
+	std::string_view slot_string_view (VM& vm, int slot_num);
+	template <typename T> T get (VM& vm, int slot_num);
+	void variable(VM& vm, const ModuleAndName& mod_and_name, int slot);
+	void variable(VM& vm, const Handle& handle, int slot);
+
+	namespace detail {
+#if __cpp_concepts >= 201907
+		template <typename... Outs, int... Indices, ConstCharTuple... Params>
+#else
+		template <typename... Outs, int... Indices, typename... Params>
+#endif
+		inline std::tuple<Outs...> variables_impl (
+			VM& vm,
+			std::integer_sequence<int, Indices...>,
+			Params&&... modules_names
+		) {
+			if constexpr (sizeof...(Outs) == 0) {
+				return {};
+			}
+			else {
+				static_assert(sizeof...(Params) == sizeof...(Outs), "Expected a module/name pair per requested output");
+				static_assert(sizeof...(Outs) == sizeof...(Indices), "Mismatching index count");
+
+				vm.ensure_slots(sizeof...(Outs));
+				(variable(vm, modules_names, Indices), ...);
+				return std::tuple<Outs...>(get<Outs>(vm, Indices)...);
+			}
+		}
+	} //namespace detail
+
+#if __cpp_concepts >= 201907
+	template <typename... Outs, detail::ConstCharTuple... Params>
+#else
+	template <typename... Outs, typename... Params>
+#endif
+	inline std::tuple<Outs...> variables(VM& vm, Params&&... modules_names) {
+		return detail::variables_impl<Outs...>(vm, std::make_integer_sequence<int, sizeof...(Outs)>(), std::forward<Params>(modules_names)...);
+	}
+
+	inline void interpret (VM& vm, const std::string& module_name, const std::string& script) {
+		return vm.interpret(module_name.c_str(), script.c_str());
+	}
+
+	inline void set (VM& vm, int slot_num, const std::string& value) {
+		vm.set_slot_string(slot_num, value.c_str());
+	}
+
+	inline void set (VM& vm, int slot_num, std::string_view value) {
+		vm.set_slot_bytes(slot_num, value.data(), value.size());
+	}
+
+	inline void set (VM& vm, int slot_num, const std::vector<char>& value) {
+		vm.set_slot_bytes(slot_num, value.data(), value.size());
+	}
+} //namespace wren