good work on argparse

CMakeLists.txt

@@ -1,6 +1,6 @@
 cmake_minimum_required(VERSION 3.20)
 include(cmake/color.cmake)
-set(BLT_VERSION 4.0.7)
+set(BLT_VERSION 4.0.8)
 
 set(BLT_TARGET BLT)
 

include/blt/parse/argparse_v2.h

@@ -87,7 +87,7 @@ namespace blt::argparse
             explicit missing_argument_error(const std::string& message): std::runtime_error(message)
             {
             }
-        }
+        };
 
         class subparse_error final : public std::exception
         {
@@ -108,31 +108,7 @@ namespace blt::argparse
                 return m_found_string;
             }
 
-            [[nodiscard]] std::string error_string() const
-            {
-                std::string message = "Subparser Error: ";
-                message += m_found_string;
-                message += " is not a valid command. Allowed commands are: {";
-                for (const auto [i, allowed_string] : enumerate(m_allowed_strings))
-                {
-                    if (allowed_string.size() > 1)
-                        message += '[';
-                    for (const auto [j, alias] : enumerate(allowed_string))
-                    {
-                        message += alias;
-                        if (j < alias.size() - 2)
-                            message += ", ";
-                        else if (j < alias.size())
-                            message += ", or ";
-                    }
-                    if (allowed_string.size() > 1)
-                        message += ']';
-                    if (i != m_allowed_strings.size() - 1)
-                        message += ' ';
-                }
-                message += "}";
-                return message;
-            }
+            [[nodiscard]] std::string error_string() const;
 
             [[nodiscard]] const char* what() const override
             {
@@ -147,18 +123,13 @@ namespace blt::argparse
         template <typename... Args>
         struct arg_data_helper_t
         {
-            using arg_primitive_data_t = std::variant<Args...>;
-            using arg_list_data_t = std::variant<std::vector<Args>...>;
+            using variant_t = std::variant<Args..., std::vector<Args>...>;
         };
 
-        using data_helper_t = arg_data_helper_t<i8, i16, i32, i64, u8, u16, u32, u64, float, double, std::string_view>;
-
-        using arg_primitive_data_t = data_helper_t::arg_primitive_data_t;
-        using arg_list_data_t = data_helper_t::arg_list_data_t;
-        using arg_data_t = std::variant<arg_primitive_data_t, arg_list_data_t>;
+        using arg_data_t = arg_data_helper_t<i8, i16, i32, i64, u8, u16, u32, u64, float, double, std::string_view>::variant_t;
 
         template <typename T>
-        struct arg_type_t
+        struct arg_string_converter_t
         {
             static T convert(const std::string_view value)
             {
@@ -201,7 +172,7 @@ namespace blt::argparse
     {
     public:
         explicit argument_string_t(const char* input, const hashset_t<char>& allowed_flag_prefix): m_argument(input),
-                                                                                                   allowed_flag_prefix(&allowed_flag_prefix)
+                                                                                                   m_allowed_flag_prefix(&allowed_flag_prefix)
         {
             if (input == nullptr)
                 throw detail::bad_flag("Argument cannot be null!");
@@ -234,10 +205,33 @@ namespace blt::argparse
         }
 
     private:
+        /**
+         * This function takes the command line argument represented by this class,
+         * stored in m_argument and converts into flag side and name side arguments.
+         *
+         * What this means is in the case of a flag provided, for example passing --foo or --bar, this function will split the argument into
+         *
+         * m_flag_section = "--"
+         * m_name_section = "foo" || "bar"
+         *
+         * If the argument is purely positional, meaning there is no flag prefix,
+         * this function will do nothing and m_flag_section will be true for .empty()
+         *
+         * For example, if you provide res/some/folder/or/file as a command line positional argument,
+         * this function will create the following internal state:
+         *
+         * m_flag_section = ""
+         * m_flag_section.empty() == true
+         * m_name_section = "res/some/folder/or/file"
+         *
+         * m_argument is not modified by this function
+         */
         void process_argument()
         {
+            // user provides a list of allowed prefix characters to argument_parser_t, which is then provided to this class at construction time
+            // it is not the job of this class to validate flag prefixes beyond this. // TODO: requiring this pointer is a code smell.
             size_t start = 0;
-            for (; start < m_argument.size() && allowed_flag_prefix->contains(m_argument[start]); start++)
+            for (; start < m_argument.size() && m_allowed_flag_prefix->contains(m_argument[start]); start++)
             {
             }
 
@@ -248,44 +242,54 @@ namespace blt::argparse
         std::string_view m_argument;
         std::string_view m_flag_section;
         std::string_view m_name_section;
-        const hashset_t<char>* allowed_flag_prefix;
+        const hashset_t<char>* m_allowed_flag_prefix;
     };
 
     class argument_consumer_t
     {
     public:
-        explicit argument_consumer_t(const span<argument_string_t>& args): m_args(args)
+        explicit argument_consumer_t(const span<argument_string_t>& args): m_begin(args.data()), m_end(args.data() + args.size())
         {
         }
 
         [[nodiscard]] argument_string_t peek(const i32 offset = 0) const
         {
-            return m_args[m_forward_index + offset];
+            return *(m_begin + offset);
+        }
+
+        [[nodiscard]] argument_string_t r_peek(const i32 offset = 0) const
+        {
+            return *(m_end - 1 - offset);
         }
 
         argument_string_t consume()
         {
-            return m_args[m_forward_index++];
+            return *(m_begin++);
         }
 
-        [[nodiscard]] i32 position() const
+        argument_string_t r_consume()
         {
-            return m_forward_index;
+            return *(--m_end);
         }
 
         [[nodiscard]] i32 remaining() const
         {
-            return static_cast<i32>(m_args.size()) - m_forward_index;
+            return static_cast<i32>(size());
         }
 
-        [[nodiscard]] bool has_next(const i32 offset = 0) const
+        [[nodiscard]] bool can_consume(const i32 amount = 0) const
         {
-            return (offset + m_forward_index) < m_args.size();
+            return amount < remaining();
         }
 
     private:
-        span<argument_string_t> m_args;
-        i32 m_forward_index = 0;
+        [[nodiscard]] ptrdiff_t size() const
+        {
+            return m_end - m_begin;
+        }
+
+        argument_string_t* m_begin;
+        argument_string_t* m_end;
     };
 
     class argument_storage_t
@@ -312,6 +316,12 @@ namespace blt::argparse
         }
 
     private:
+        void add(const argument_storage_t& values)
+        {
+            for (const auto value : values)
+                m_data.insert(value);
+        }
+
         hashmap_t<std::string_view, detail::arg_data_t> m_data;
     };
 
@@ -322,33 +332,47 @@ namespace blt::argparse
     public:
         argument_builder_t()
         {
-            dest_func = [](const std::string_view dest, argument_storage_t& storage, std::string_view value)
+            m_dest_func = [](const std::string_view dest, argument_storage_t& storage, std::string_view value)
             {
-                storage.m_data[dest] = value;
+                storage.m_data.insert({dest, value});
+            };
+            m_dest_vec_func = [](const std::string_view dest, argument_storage_t& storage, const std::vector<std::string_view>& values)
+            {
+                storage.m_data.insert({dest, values});
             };
         }
 
         template <typename T>
         argument_builder_t& as_type()
         {
-            dest_func = [](const std::string_view dest, argument_storage_t& storage, std::string_view value)
+            m_dest_func = [](const std::string_view dest, argument_storage_t& storage, std::string_view value)
             {
-                storage.m_data[dest] = detail::arg_type_t<T>::convert(value);
+                storage.m_data.insert({dest, detail::arg_string_converter_t<T>::convert(value)});
+            };
+            m_dest_vec_func = [](const std::string_view dest, argument_storage_t& storage, const std::vector<std::string_view>& values)
+            {
+                std::vector<T> converted_values;
+                for (const auto& value : values)
+                    converted_values.push_back(detail::arg_string_converter_t<T>::convert(value));
+                storage.m_data.insert({dest, converted_values});
             };
             return *this;
         }
 
     private:
-        action_t action = action_t::STORE;
-        bool required = false; // do we require this argument to be provided as an argument?
-        nargs_v nargs = 1; // number of arguments to consume
-        std::optional<std::string> metavar; // variable name to be used in the help string
-        std::optional<std::string> help; // help string to be used in the help string
-        std::optional<std::vector<std::string>> choices; // optional allowed choices for this argument
-        std::optional<std::string> default_value;
-        std::optional<std::string> const_value;
+        action_t m_action = action_t::STORE;
+        bool m_required = false; // do we require this argument to be provided as an argument?
+        nargs_v m_nargs = 1; // number of arguments to consume
+        std::optional<std::string> m_metavar; // variable name to be used in the help string
+        std::optional<std::string> m_help; // help string to be used in the help string
+        std::optional<std::vector<std::string>> m_choices; // optional allowed choices for this argument
+        std::optional<detail::arg_data_t> m_default_value;
+        std::optional<detail::arg_data_t> m_const_value;
+        std::optional<std::string> m_dest;
         // dest, storage, value input
-        std::function<void(std::string_view, argument_storage_t&, std::string_view)> dest_func;
+        std::function<void(std::string_view, argument_storage_t&, std::string_view)> m_dest_func;
+        // dest, storage, value input
+        std::function<void(std::string_view, argument_storage_t&, const std::vector<std::string_view>& values)> m_dest_vec_func;
     };
 
     class argument_parser_t
@@ -370,7 +394,7 @@ namespace blt::argparse
                                                         std::string_view, Aliases>>...>,
                 "Arguments must be of type string_view, convertible to string_view or be string_view constructable");
             m_argument_builders.emplace_back();
-            m_flag_arguments[arg] = &m_argument_builders.back();
+            m_flag_arguments.insert({arg, &m_argument_builders.back()});
             ((m_flag_arguments[std::string_view{aliases}] = &m_argument_builders.back()), ...);
             return m_argument_builders.back();
         }
@@ -378,16 +402,18 @@ namespace blt::argparse
         argument_builder_t& add_positional(const std::string_view arg)
         {
             m_argument_builders.emplace_back();
-            m_positional_arguments[arg] = &m_argument_builders.back();
+            m_positional_arguments.insert({arg, &m_argument_builders.back()});
             return m_argument_builders.back();
         }
 
         argument_subparser_t& add_subparser(std::string_view dest);
 
-        void parse(argument_consumer_t& consumer); // NOLINT
+        argument_storage_t parse(argument_consumer_t& consumer); // NOLINT
 
         void print_help();
 
+        void print_usage();
+
         argument_parser_t& set_name(const std::string_view name)
         {
             m_name = name;
@@ -428,6 +454,11 @@ namespace blt::argparse
         }
 
     private:
+        void parse_flag(argument_storage_t& parsed_args, argument_consumer_t& consumer, std::string_view arg);
+        void parse_positional(argument_storage_t& parsed_args, argument_consumer_t& consumer, std::string_view arg);
+        static void handle_missing_and_default_args(hashmap_t<std::string_view, argument_builder_t*>& arguments, const hashset_t<std::string_view>& found,
+                                             argument_storage_t& parsed_args, std::string_view type);
+
         std::optional<std::string> m_name;
         std::optional<std::string> m_usage;
         std::optional<std::string> m_description;
@@ -470,7 +501,7 @@ namespace blt::argparse
          *
          * @throws detail::subparse_error If the argument is a flag or does not match any known parser.
          */
-        argument_string_t parse(argument_consumer_t& consumer); // NOLINT
+        std::pair<argument_string_t, argument_storage_t> parse(argument_consumer_t& consumer); // NOLINT
 
     private:
         [[nodiscard]] std::vector<std::vector<std::string_view>> get_allowed_strings() const;

src/blt/parse/argparse_v2 (conflicted copy 2025-02-13 150255).cpp

@@ -155,7 +155,7 @@ namespace blt::argparse
     void argument_string_t::process_argument()
     {
         size_t start = 0;
-        for (; start < m_argument.size() && allowed_flag_prefix->contains(m_argument[start]); start++)
+        for (; start < m_argument.size() && m_allowed_flag_prefix->contains(m_argument[start]); start++)
         {
         }
 

src/blt/parse/argparse_v2.cpp

@@ -21,12 +21,6 @@
 
 namespace blt::argparse
 {
-    namespace detail
-    {
-
-    }
-
-
     namespace detail
     {
         // Unit Tests for class argument_string_t
@@ -122,7 +116,6 @@ namespace blt::argparse
             BLT_ASSERT(arg.get_flag() == "++" && "Double plus value should match the input string.");
         }
 
-        
 
         void run_all_tests_argument_string_t()
         {
@@ -144,6 +137,32 @@ namespace blt::argparse
         {
             run_all_tests_argument_string_t();
         }
+
+        [[nodiscard]] std::string subparse_error::error_string() const
+        {
+            std::string message = "Subparser Error: ";
+            message += m_found_string;
+            message += " is not a valid command. Allowed commands are: {";
+            for (const auto [i, allowed_string] : enumerate(m_allowed_strings))
+            {
+                if (allowed_string.size() > 1)
+                    message += '[';
+                for (const auto [j, alias] : enumerate(allowed_string))
+                {
+                    message += alias;
+                    if (j < alias.size() - 2)
+                        message += ", ";
+                    else if (j < alias.size())
+                        message += ", or ";
+                }
+                if (allowed_string.size() > 1)
+                    message += ']';
+                if (i != m_allowed_strings.size() - 1)
+                    message += ' ';
+            }
+            message += "}";
+            return message;
+        }
     }
 
     argument_subparser_t& argument_parser_t::add_subparser(const std::string_view dest)
@@ -152,44 +171,162 @@ namespace blt::argparse
         return m_subparsers.back().second;
     }
 
-    void argument_parser_t::parse(argument_consumer_t& consumer)
+    argument_storage_t argument_parser_t::parse(argument_consumer_t& consumer)
     {
-        if (!consumer.has_next())
+        hashset_t<std::string_view> found_flags;
+        hashset_t<std::string_view> found_positional;
+        argument_storage_t parsed_args;
+        // first, we consume flags which may be part of this parser
+        while (consumer.can_consume() && consumer.peek().is_flag())
         {
-            if (m_subparsers.size() > 0)
+            const auto key = consumer.consume();
+            const auto flag = m_flag_arguments.find(key.get_argument());
+            if (flag == m_flag_arguments.end())
             {
-                std::cout << ""
-                print_help();
-                return;
+                std::cerr << "Error: Unknown flag: " << key.get_argument() << std::endl;
+                exit(1);
+            }
+            found_flags.insert(key.get_argument());
+            parse_flag(parsed_args, consumer, key.get_argument());
+        }
+        try
+        {
+            for (auto& [key, subparser] : m_subparsers)
+            {
+                auto [parsed_subparser, storage] = subparser.parse(consumer);
+                storage.m_data.insert({key, detail::arg_data_t{parsed_subparser.get_argument()}});
+                parsed_args.add(storage);
             }
         }
+        catch (const detail::missing_argument_error& e)
+        {
+            std::cerr << "Error: " << e.what() << std::endl;
+            print_usage();
+            exit(1);
+        } catch (const detail::subparse_error& e)
+        {
+            std::cerr << e.error_string() << std::endl;
+            exit(1);
+        }
+        while (consumer.can_consume())
+        {
+            const auto key = consumer.consume();
+            if (key.is_flag())
+            {
+                const auto flag = m_flag_arguments.find(key.get_argument());
+                if (flag == m_flag_arguments.end())
+                {
+                    std::cerr << "Error: Unknown flag: " << key.get_argument() << std::endl;
+                    exit(1);
+                }
+                found_flags.insert(key.get_argument());
+                parse_flag(parsed_args, consumer, key.get_argument());
+            }
+            else
+            {
+                const auto pos = m_positional_arguments.find(key.get_argument());
+                if (pos == m_positional_arguments.end())
+                {
+                    std::cerr << "Error: Unknown positional argument: " << key.get_argument() << std::endl;
+                    exit(1);
+                }
+                found_positional.insert(key.get_argument());
+                parse_positional(parsed_args, consumer, key.get_argument());
+            }
+        }
+        handle_missing_and_default_args(m_flag_arguments, found_flags, parsed_args, "flag");
+        handle_missing_and_default_args(m_positional_arguments, found_positional, parsed_args, "positional");
+
+        return parsed_args;
     }
 
     void argument_parser_t::print_help()
     {
-
     }
 
-    argument_string_t argument_subparser_t::parse(argument_consumer_t& consumer)
+    void argument_parser_t::print_usage()
     {
-        if (!consumer.has_next())
+    }
+
+    void argument_parser_t::parse_flag(argument_storage_t& parsed_args, argument_consumer_t& consumer, const std::string_view arg)
+    {
+        auto& flag = m_flag_arguments[arg];
+        auto dest = flag->m_dest.value_or(arg);
+        std::visit(lambda_visitor{
+                       [&parsed_args, &consumer, &dest, &flag, arg](const nargs_t arg_enum)
+                       {
+                           switch (arg_enum)
+                           {
+                           case nargs_t::IF_POSSIBLE:
+                               if (consumer.can_consume() && !consumer.peek().is_flag())
+                                   flag->m_dest_func(dest, parsed_args, consumer.consume().get_argument());
+                               else
+                               {
+                                   if (flag->m_const_value)
+                                       parsed_args.m_data.insert({dest, *flag->m_const_value});
+                               }
+                               break;
+                           [[fallthrough]] case nargs_t::ALL_AT_LEAST_ONE:
+                               if (!consumer.can_consume())
+                                   std::cout << "Error expected at least one argument to be consumed by '" << arg << '\'' << std::endl;
+                           case nargs_t::ALL:
+                               std::vector<std::string_view> args;
+                               while (consumer.can_consume() && !consumer.peek().is_flag())
+                                   args.emplace_back(consumer.consume().get_argument());
+                               flag->m_dest_vec_func(dest, parsed_args, args);
+                               break;
+                           }
+                       },
+                       [](const i32 argc)
+                       {
+                       }
+                   }, flag->m_nargs);
+    }
+
+    void argument_parser_t::parse_positional(argument_storage_t& parsed_args, argument_consumer_t& consumer, const std::string_view arg)
+    {
+    }
+
+    void argument_parser_t::handle_missing_and_default_args(hashmap_t<std::string_view, argument_builder_t*>& arguments,
+                                                            const hashset_t<std::string_view>& found, argument_storage_t& parsed_args,
+                                                            const std::string_view type)
+    {
+        for (const auto& [key, value] : arguments)
+        {
+            if (!found.contains(key))
+            {
+                if (value->m_required)
+                {
+                    std::cerr << "Error: " << type << " argument '" << key << "' was not found but is required by the program" << std::endl;
+                    exit(1);
+                }
+                auto dest = value->m_dest.value_or(key);
+                if (value->m_default_value && !parsed_args.contains(dest))
+                    parsed_args.m_data.insert({dest, *value->m_default_value});
+            }
+        }
+    }
+
+    std::pair<argument_string_t, argument_storage_t> argument_subparser_t::parse(argument_consumer_t& consumer)
+    {
+        if (!consumer.can_consume())
             throw detail::missing_argument_error("Subparser requires an argument.");
         const auto key = consumer.consume();
         if (key.is_flag())
             throw detail::subparse_error(key.get_argument(), get_allowed_strings());
         const auto it = m_parsers.find(key.get_name());
+        argument_parser_t* parser;
         if (it == m_parsers.end())
         {
             const auto it2 = m_aliases.find(key.get_name());
             if (it2 == m_aliases.end())
                 throw detail::subparse_error(key.get_argument(), get_allowed_strings());
-            it2->second->m_name = m_parent->m_name;
-            it2->second->parse(consumer);
-            return key;
+            parser = it2->second;
         }
-        it->second.m_name = m_parent->m_name;
-        it->second.parse(consumer);
-        return key;
+        else
+            parser = &it->second;
+        parser->m_name = m_parent->m_name;
+        return {key, parser->parse(consumer)};
     }
 
     std::vector<std::vector<std::string_view>> argument_subparser_t::get_allowed_strings() const