fourdst::config Namespace Reference

Namespaces
namespace	exceptions

Classes
class	Config
	Wrapper class for managing strongly-typed configuration structures. More...
struct	InspectType
struct	is_config_wrapper
	Type trait to determine if a type is a Config wrapper. More...
struct	is_config_wrapper< Config< T > >
	Specialization of is_config_wrapper for Config<T>. More...

Concepts
concept	IsConfigSchema
	Concept ensuring a type is suitable for configuration schema.
concept	IsCLIApp
	Concept that defines the requirements for a CLI application class.

Enumerations
enum class	RootNameLoadPolicy { FROM_FILE , KEEP_CURRENT }
	Policies for handling the root name during configuration loading. More...
enum class	ConfigState { DEFAULT , LOADED_FROM_FILE }
	Represents the current state of a Config object. More...

Functions
template<typename T, typename CliApp>
void	register_as_cli (T &config, CliApp &app, const std::string &prefix="")
	Registers configuration structure fields as CLI options.

Enumeration Type Documentation

ConfigState

enum class fourdst::config::ConfigState

strong

Represents the current state of a Config object.

Enumerator
DEFAULT	Configuration contains default values and has not been loaded from a file.
LOADED_FROM_FILE	Configuration has been successfully populated from a file.

RootNameLoadPolicy

enum class fourdst::config::RootNameLoadPolicy

strong

Policies for handling the root name during configuration loading.

Enumerator
FROM_FILE	Updates the internal root name to match what is found in the file.
KEEP_CURRENT	Enforces the current internal root name; loading fails if the file's root name differs.

Function Documentation

register_as_cli()

template<typename T, typename CliApp>

void fourdst::config::register_as_cli	(	T &	config,
		CliApp &	app,
		const std::string &	prefix = "" )

Registers configuration structure fields as CLI options.

This function iterates over the members of the provided configuration object using reflection and registers each member as a command-line option in the provided CLI application.

If the configuration object contains nested structures, field names are flattened using dot notation (e.g., parent.child.field).

If T is a Config<U> wrapper, it automatically unwraps the inner value and adds a footer note to the CLI application's help message indicating that options were auto-generated.

Template Parameters

T	The type of the configuration object. Can be a raw struct or a Config<Struct> wrapper.
CliApp	The type of the CLI application object. Must satisfy the IsCLIApp concept (e.g., CLI::App).

Parameters

config	The configuration object to register.
app	The CLI application instance to add options to.
prefix	Optional prefix for option names. Used internally for recursion; usually omitted by the caller.

Examples

Basic usage with CLI11:

#include "CLI/CLI.hpp"
#include "fourdst/config/config.h"
 
struct MyOptions {
    int verbosity = 0;
    std::string input_file = "data.txt";
};
 
int main(int argc, char** argv) {
    fourdst::config::Config<MyOptions> cfg;
    CLI::App app{"My Application"};
 
    // Automatically adds flags: --verbosity, --input_file
    fourdst::config::register_as_cli(cfg, app);
 
    CLI11_PARSE(app, argc, argv);
 
    // cfg is now populated with values from CLI
    return 0;
}

Nested structures:

struct Server {
    int port = 8080;
    std::string host = "localhost";
};
 
struct AppConfig {
    Server server;
    bool dry_run = false;
};
 
// In main...
fourdst::config::Config<AppConfig> cfg;
// Registers: --server.port, --server.host, --dry_run
fourdst::config::register_as_cli(cfg, app);