Base class for command-line flag handling. More...

#include <flag.hpp>

Inheritance diagram for by::flag:

Public Types
enum	res { MATCH , EXIT_PROGRAM , NOT_MATCH }

Public Member Functions
virtual const nchar *	getName () const =0

virtual const nchar *	getDescription () const =0

virtual res	take (interpreter &ip, starter &s, cli &c, flagArgs &a, errReport &rpt) const

nbool	canTake (const std::string &pattern) const

Public Member Functions inherited from by::instance
	instance (id newId)

	instance (const me &rhs)

me &	operator= (const me &rhs)=default

void *	operator new (size_t sz) noexcept

void	operator delete (void *pt, size_t sz) noexcept

virtual id	getId () const

virtual nbool	isHeap () const
	Checks if this instance is allocated on the heap.

const life *	getBindTag () const
	Returns a pointer to the associated life object for reference counting.

Public Member Functions inherited from by::typeProvidable
nbool	operator== (const me &rhs) const

nbool	operator!= (const me &rhs) const

virtual const type &	getType () const =0

nbool	isSub (const type &it) const

nbool	isSub (const type *it) const BY_SIDE_FUNC(isSub)

nbool	isSub (const me &it) const

nbool	isSub (const me *it) const BY_SIDE_FUNC(isSub)

nbool	isSuper (const type &it) const

nbool	isSuper (const type *it) const BY_SIDE_FUNC(isSuper)

nbool	isSuper (const me &it) const

nbool	isSuper (const me *it) const BY_SIDE_FUNC(isSuper)

template<typename T >
nint	isSub () const

template<typename T >
nint	isSuper () const

template<typename T >
T *	cast ()

template<typename T >
const T *	cast () const BY_CONST_FUNC(cast< T >()) virtual void *cast(const type &to)
	Safe cast to target type using type hierarchy information.

const void *	cast (const type &to) const BY_CONST_FUNC(cast(to)) void cast(const type it) BY_SIDE_FUNC(cast)

Public Member Functions inherited from by::clonable
virtual me *	clone () const =0

virtual me *	cloneDeep () const

virtual void	onCloneDeep (const me &from)

Protected Member Functions
virtual ncnt	getArgCount () const

void	_delArgs (flagArgs &a, ncnt deleteOptionCnt) const
	Deletes arguments from the `flagArgs` list.

virtual const strings &	_getRegExpr () const =0

virtual res	_onTake (const flagArgs &tray, cli &c, interpreter &ip, starter &s, errReport &rpt) const =0

Protected Member Functions inherited from by::instance
nbool	_setId (id new1)

Additional Inherited Members
Static Public Member Functions inherited from by::instance
static vault &	getVault ()

Static Protected Member Functions inherited from by::instance
static instancer *	_getMgr ()

Detailed Description

Base class for command-line flag handling.

Handles flags commonly seen in shell-based programs. Note this class doesn't represent a flag like --version, but rather handles whether such flags exist and what actions to take.

Flag descriptions

Each flag defines not only its name but also a description of its functionality. These are used by helpFlag.

Regex pattern matching

Each flag class has a defined pattern to search for. For example, verFlag searches for the --version string in program arguments. If found, it retrieves version info from buildFeature and outputs it. This behavior works by calling flag::take(), which uses the regex defined in each derived class's _getRegExpr() to find the desired pattern. Since regex is used, flag order is ignored.

Multiple patterns can be defined in regex:

const strings& me::_getRegExpr() const {
    static strings inner{"^\\-S$", "^\\--show-structure$"};
    return inner;
}

Matches either ^\-S$ or ^\--show-structure$.

Consuming multiple flag arguments

Consider verFlag: when --version exists in arguments, it outputs version. After operating, it removes --version from flagArgs to prevent verFlag from running again.

Now consider bufferSrcFlag, used like: --script "main() void: print(\"wow!\")"

Breaking this down: --script indicates flag start, followed by space and "<your code>" which is the frontend code body argument to execute. Some flags consume not just the matched pattern but additional arguments. Each derived flag class can override getArgCount() to specify how many additional arguments to extract.

Terminating flags

bufferSrcFlag needs preliminary work before program start. Conversely, verFlag immediately outputs version and terminates without interpretation once matched (as most programs do). To terminate immediately after matching, override _onTake() to return EXIT_PROGRAM. For continued operation like bufferSrcFlag, return MATCH.

Member Function Documentation

◆ _delArgs()

void by::flag::_delArgs	(	flagArgs &	a,
		ncnt	deleteOptionCnt ) const

protected

Deletes arguments from the flagArgs list.

This method is used internally to remove arguments that have been consumed by this flag, preventing them from being processed again by other flags.

Parameters

a	The `flagArgs` instance from which arguments are to be deleted.
deleteOptionCnt	a count indicating how much arguments to delete.

◆ canTake()

nbool by::flag::canTake ( const std::string & pattern ) const

Parameters

pattern it's used to determine whether a pattern for a flag or not. it usually starts with one or two hyphens.

◆ getArgCount()

virtual ncnt by::flag::getArgCount ( ) const

protectedvirtual

when this flag matched to one of args, the value of returning this func will be count of continuous argument of this flag.

Reimplemented in by::bufferSrcFlag.

◆ take()

virtual res by::flag::take	(	interpreter &	ip,
		starter &	s,
		cli &	c,
		flagArgs &	a,
		errReport &	rpt ) const

virtual

Returns: false if flag wants to exit program.

The documentation for this class was generated from the following file:

/home/runner/work/byeol/byeol/module/frontend/flag/flag.hpp

Public Types

Public Member Functions

Protected Member Functions

Additional Inherited Members