chore: improve error generation. exit on missing required arg. remove redundant fake_parser.

src/headers/parser/argument_parser.hpp

@@ -20,6 +20,32 @@
 #include <vector>
 
 namespace argument_parser {
+	namespace internal::sfinae {
+		template <typename T> struct has_format_hint {
+		private:
+			typedef char YesType[1];
+			typedef char NoType[2];
+
+			template <typename C> static YesType &test(decltype(&C::format_hint));
+			template <typename> static NoType &test(...);
+
+		public:
+			static constexpr bool value = sizeof(test<T>(0)) == sizeof(YesType);
+		};
+
+		template <typename T> struct has_purpose_hint {
+		private:
+			typedef char YesType[1];
+			typedef char NoType[2];
+
+			template <typename C> static YesType &test(decltype(&C::purpose_hint));
+			template <typename> static NoType &test(...);
+
+		public:
+			static constexpr bool value = sizeof(test<T>(0)) == sizeof(YesType);
+		};
+	} // namespace internal::sfinae
+
 	namespace internal::atomic {
 		template <typename T> class copyable_atomic {
 		public:
@@ -72,6 +98,7 @@ namespace argument_parser {
 		[[nodiscard]] virtual bool expects_parameter() const = 0;
 		virtual void invoke() const = 0;
 		virtual void invoke_with_parameter(const std::string &param) const = 0;
+		[[nodiscard]] virtual std::pair<std::string, std::string> get_trait_hints() const = 0;
 		[[nodiscard]] virtual std::unique_ptr<action_base> clone() const = 0;
 	};
 
@@ -92,8 +119,31 @@ namespace argument_parser {
 		}
 
 		void invoke_with_parameter(const std::string &param) const override {
+			bool parse_success = false;
+			try {
 				T parsed_value = parsing_traits::parser_trait<T>::parse(param);
+				parse_success = true;
 				invoke(parsed_value);
+			} catch (const std::runtime_error &e) {
+				if (!parse_success) {
+					auto [format_hint, purpose_hint] = get_trait_hints();
+					if (purpose_hint.empty())
+						purpose_hint = "value";
+					std::string error_text{"'" + param + "' is not a valid " + purpose_hint + " ${KEY}"};
+					if (!format_hint.empty())
+						error_text += "\nExpected format: " + format_hint;
+					throw std::runtime_error(error_text);
+				}
+			}
+		}
+
+		[[nodiscard]] std::pair<std::string, std::string> get_trait_hints() const override {
+			if constexpr (internal::sfinae::has_format_hint<parsing_traits::parser_trait<T>>::value &&
+						  internal::sfinae::has_purpose_hint<parsing_traits::parser_trait<T>>::value) {
+				return {parsing_traits::parser_trait<T>::format_hint, parsing_traits::parser_trait<T>::purpose_hint};
+			} else {
+				return {"", "value"};
+			}
 		}
 
 		[[nodiscard]] std::unique_ptr<action_base> clone() const override {
@@ -120,6 +170,10 @@ namespace argument_parser {
 			invoke();
 		}
 
+		[[nodiscard]] std::pair<std::string, std::string> get_trait_hints() const override {
+			return {"", ""};
+		}
+
 		[[nodiscard]] std::unique_ptr<action_base> clone() const override {
 			return std::make_unique<non_parametered_action>(handler);
 		}

src/headers/parser/parser_v2.hpp

@@ -15,10 +15,6 @@
 #include <vector>
 
 namespace argument_parser::v2 {
-	namespace internal {
-		static inline fake_parser fake_parser{};
-	}
-
 	enum class add_argument_flags { ShortArgument, LongArgument, HelpText, Action, Required };
 
 	namespace flags {
@@ -104,30 +100,6 @@ namespace argument_parser::v2 {
 		}
 
 	private:
-		template <typename T> struct has_format_hint {
-		private:
-			typedef char YesType[1];
-			typedef char NoType[2];
-
-			template <typename C> static YesType &test(decltype(&C::format_hint));
-			template <typename> static NoType &test(...);
-
-		public:
-			static constexpr bool value = sizeof(test<T>(0)) == sizeof(YesType);
-		};
-
-		template <typename T> struct has_purpose_hint {
-		private:
-			typedef char YesType[1];
-			typedef char NoType[2];
-
-			template <typename C> static YesType &test(decltype(&C::purpose_hint));
-			template <typename> static NoType &test(...);
-
-		public:
-			static constexpr bool value = sizeof(test<T>(0)) == sizeof(YesType);
-		};
-
 		template <bool IsTyped, typename ActionType, typename T, typename ArgsMap>
 		void add_argument_impl(ArgsMap const &argument_pairs) {
 			std::unordered_map<extended_add_argument_flags, bool> found_params{
@@ -174,8 +146,8 @@ namespace argument_parser::v2 {
 				switch (suggested_add) {
 				case candidate_type::typed_action:
 					if (help_text.empty()) {
-						if constexpr (has_format_hint<parsing_traits::parser_trait<T>>::value &&
-									  has_purpose_hint<parsing_traits::parser_trait<T>>::value) {
+						if constexpr (internal::sfinae::has_format_hint<parsing_traits::parser_trait<T>>::value &&
+									  internal::sfinae::has_purpose_hint<parsing_traits::parser_trait<T>>::value) {
 							auto format_hint = parsing_traits::parser_trait<T>::format_hint;
 							auto purpose_hint = parsing_traits::parser_trait<T>::purpose_hint;
 							help_text = "Triggers action with " + std::string(purpose_hint) + " (" +
@@ -190,8 +162,8 @@ namespace argument_parser::v2 {
 					break;
 				case candidate_type::store_other:
 					if (help_text.empty()) {
-						if constexpr (has_format_hint<parsing_traits::parser_trait<T>>::value &&
-									  has_purpose_hint<parsing_traits::parser_trait<T>>::value) {
+						if constexpr (internal::sfinae::has_format_hint<parsing_traits::parser_trait<T>>::value &&
+									  internal::sfinae::has_purpose_hint<parsing_traits::parser_trait<T>>::value) {
 							auto format_hint = parsing_traits::parser_trait<T>::format_hint;
 							auto purpose_hint = parsing_traits::parser_trait<T>::purpose_hint;
 							help_text =

src/main.cpp

@@ -1,6 +1,5 @@
-#include "headers/parser/parsing_traits/traits.hpp"
+#include <exception>
 #include <string>
-#define ALLOW_DASH_FOR_WINDOWS 0
 
 #include <argparse>
 #include <fstream>
@@ -24,7 +23,7 @@ template <> struct argument_parser::parsing_traits::parser_trait<Point> {
 		return {x, y};
 	}
 	static constexpr argument_parser::parsing_traits::hint_type format_hint = "x,y";
-	static constexpr argument_parser::parsing_traits::hint_type purpose_hint = "point coordinates";
+	static constexpr argument_parser::parsing_traits::hint_type purpose_hint = "coordinates";
 };
 
 template <> struct argument_parser::parsing_traits::parser_trait<std::regex> {
@@ -178,11 +177,9 @@ int v2Examples() {
 }
 
 int main() {
-	return v2Examples();
-
 	try {
+		return v2Examples();
 	} catch (std::exception const &e) {
-		std::cerr << "Error: " << e.what() << std::endl;
-		return -1;
+		std::cout << e.what() << std::endl;
 	}
 }

src/source/parser/argument_parser.cpp

@@ -225,6 +225,17 @@ namespace argument_parser {
 		}
 	}
 
+	std::string replace_var(std::string text, const std::string &var_name, const std::string &value) {
+		std::string placeholder = "${" + var_name + "}";
+		size_t pos = text.find(placeholder);
+
+		while (pos != std::string::npos) {
+			text.replace(pos, placeholder.length(), value);
+			pos = text.find(placeholder, pos + value.length());
+		}
+		return text;
+	}
+
 	void base_parser::invoke_arguments(std::unordered_map<std::string, std::string> const &values_for_arguments,
 									   std::vector<std::pair<std::string, argument>> &found_arguments,
 									   std::optional<argument> const &found_help) {
@@ -244,7 +255,9 @@ namespace argument_parser {
 				}
 				value.set_invoked(true);
 			} catch (const std::runtime_error &e) {
-				error_stream << "Argument " << key << " failed with: " << e.what() << "\n";
+				std::string err{e.what()};
+				err = replace_var(err, "KEY", "for " + key);
+				error_stream << "Error: " << err << "\n";
 			}
 		}
 
@@ -367,6 +380,7 @@ namespace argument_parser {
 			}
 			std::cerr << "\n";
 			display_help(convention_types);
+			std::exit(1);
 		}
 	}