core.cxxm

/// SPDX-License-Identifier: Apache 2.0
/// @file cmdline.cxxm
/// @brief Kernel command-line parameter registry and parser.
 
export module zxfoundation.base.cmdline.core;
import zxfoundation.base.types;
import std;
 
export {
 
namespace zxfoundation::base::cmdline {
 
    constexpr usize MAX_PARAMS = 64;
 
    /// @brief How a parameter's value is interpreted.
    enum class value_type : u8 {
        flag,     ///< Presence-only boolean; sets @c *(bool*)storage = true.
        str,      ///< String value copied into storage buffer.
        u64,      ///< Unsigned 64-bit integer.
        boolean,  ///< 0/1, on/off, true/false, yes/no — sets @c *(bool*)storage.
        callback, ///< Custom handler: @c handler(value) is called.
    };
 
    /// @brief Signature for @c value_type::callback handlers.
    /// @param value  The token after '=', or empty for flags.
    /// @return true on success, false to abort parsing.
    using handler_fn = auto (*)(std::string_view value) noexcept -> bool;
 
    /// @brief Descriptor for a single cmdline parameter.
    struct param {
        std::string_view name{};
        value_type  type;
        handler_fn  handler{nullptr}; ///< null = use default dispatch for type.
        void*       storage{nullptr}; ///< Pointer to the target variable.
        usize       storage_size{0};  ///< For str: capacity in bytes.
        std::string_view help{};      ///< Human-readable description.
    };
 
    /// @brief Look up a registered parameter by name.
    /// @return Pointer to the param, or nullptr.
    [[nodiscard]] auto find(std::string_view name) noexcept -> param*;
 
    /// @brief Register a cmdline parameter.
    /// @return true on success, false if table is full or duplicate name.
    auto add(const param& p) noexcept -> bool;
 
    /// @brief Parse a complete command line against registered parameters.
    auto parse(std::string_view cmdline) noexcept -> void;
 
} // namespace zxfoundation::base::cmdline
 
} // end export