program_option< ValueType > Struct Template Reference

The program_option type is a wrapper that implements a useful subset of Boost's Program Options utility. More...

Public Member Functions
bool	has_value () const
	Return whether the option was set.
	operator ValueType () const
	Get the value, which must exist.
template<class F = decltype((default_check))>
	program_option (const char *name, const char *help, size_t count, F &&check=default_check)
	Construct a positional program option.
template<class F = decltype((default_check))>
	program_option (const char *section, const char *flag, const char *help, std::initializer_list< initializer_value > values={}, F &&check=default_check)
	Construct a program option.
ValueType	value () const
	Get the value, which must exist.

Detailed Description

template<typename ValueType>
struct flecsi::program_option< ValueType >

The program_option type is a wrapper that implements a useful subset of Boost's Program Options utility.

Creating an instance of this type at namespace scope will add a program option that can be queried after the initialize function is called.

A validation function can have the signature bool(ValueType,std::stringstream&) or bool(flecsi::any,std::stringstream&). An error message may be written to the stream. In the latter, deprecated case, use option_value to obtain the ValueType.

Constructor & Destructor Documentation

program_option() [1/2]

template<typename ValueType >

template<class F = decltype((default_check))>

program_option	(	const char *	section,
		const char *	flag,
		const char *	help,
		std::initializer_list< initializer_value >	values = {},
		F &&	check = default_check
	)

Construct a program option.

Parameters

section	The options description label.
flag	The command-line option in long, short, or dual form, e.g., "option,o" -> --option or -o.
help	The help message for the option.
values	Mechanism to set optional value attributes. Supported keys are option_default, option_implicit, option_zero, and option_multi. If an option_default value is specified, it will be used if the flag is not passed to the command line. If an option_implicit value is specified, it will be used if the flag is passed to the command line without a value. If option_zero is passed, the flag will not take any values, and must have an option_implicit value specified. If option_multi is passed, the flag will take multiple values.
check	An optional, user-defined predicate to validate the option passed by the user; see signature below.

program_option<int> my_flag("My Section",
  "flag,f",
  "Specify the flag [0-9].",
  {
    {option_default, 1},
    {option_implicit, 0}
  },
  [](int value, std::stringstream &) {
    return value >= 0 && value < 10;
  });

program_option() [2/2]

template<typename ValueType >

template<class F = decltype((default_check))>

program_option	(	const char *	name,
		const char *	help,
		size_t	count,
		F &&	check = default_check
	)

Construct a positional program option.

Parameters

name	The name for the positional option.
help	The help message for the option.
count	The number of values to consume for this positional option. If -1 is passed, this option will consume all remaining values.
check	An optional, user-defined predicate to validate the option passed by the user.

Member Function Documentation

value()

template<typename ValueType >

ValueType value

(

)

const

Get the value, which must exist.

operator ValueType()

template<typename ValueType >

operator ValueType

(

)

const

Get the value, which must exist.

has_value()

template<typename ValueType >

bool has_value

(

)

const

Return whether the option was set.