Optional Arguments - Revision history

Srslyyyy: /* Use of the optional arguments */

2023-08-04T16:52:10Z

Use of the optional arguments

← Older revision		Revision as of 16:52, 4 August 2023
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	You can use:		You can use:

	<syntaxhighlight lang="lua">local ~~myAwensomeVehicle~~ = createVehicle( getVehicleModelFromName( "Infernus" ), 0, 0, 5, nil, nil, 180 )</syntaxhighlight>		<syntaxhighlight lang="lua">local myAwesomeVehicle = createVehicle( getVehicleModelFromName( "Infernus" ), 0, 0, 5, nil, nil, 180 )</syntaxhighlight>

	And the result will be an Infernus rotated 180 degrees in the Z axis in the center of the map.		And the result will be an Infernus rotated 180 degrees in the Z axis in the center of the map.

Srslyyyy: /* Use of the optional arguments */

2023-08-04T16:51:32Z

Use of the optional arguments

← Older revision		Revision as of 16:51, 4 August 2023
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	Optional argument are used just like normal arguments. The only difference is that they will default to a certain value if no provided (in other words, if optionalArgument == nil then optionalArgument = defaultValue).		Optional argument are used just like normal arguments. The only difference is that they will default to a certain value if no provided (in other words, if optionalArgument == nil then optionalArgument = defaultValue).

	One common problem to new scripters is when they want to provide only an optional argument, without setting the ones that are before it. Well, this is really simple to "fix". Normally, they can be set to ''[[nil]]'', so they will default to its corresponding values while the scripter is still able to set the one he really wants to. For example, if you want to only set the rotation in Z axis of the [[createVehicle]] function (and don't know that ''rx'' and ''ry'' ~~defualt~~ to zero):		One common problem to new scripters is when they want to provide only an optional argument, without setting the ones that are before it. Well, this is really simple to "fix". Normally, they can be set to ''[[nil]]'', so they will default to its corresponding values while the scripter is still able to set the one he really wants to. For example, if you want to only set the rotation in Z axis of the [[createVehicle]] function (and don't know that ''rx'' and ''ry'' default to zero):

	<syntaxhighlight lang="lua">vehicle createVehicle ( int model, float x, float y, float z, [ float rx, float ry, float rz ] )</syntaxhighlight>		<syntaxhighlight lang="lua">vehicle createVehicle ( int model, float x, float y, float z, [ float rx, float ry, float rz ] )</syntaxhighlight>
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	And the result will be an Infernus rotated 180 degrees in the Z axis in the center of the map.		And the result will be an Infernus rotated 180 degrees in the Z axis in the center of the map.
	{{Warning\|There are some built-in MTA: SA functions that don't follow this convention, especially when an optional argument is closely related to another (e.g. color arguments in DX functions, and probably others): instead of replacing the ''nil'' value, they output a 'bad argument' error and do nothing. '''Always check if this works with a function before using it in a script'''.\|1}}		{{Warning\|There are some built-in MTA: SA functions that don't follow this convention, especially when an optional argument is closely related to another (e.g. color arguments in DX functions, and probably others): instead of replacing the ''nil'' value, they output a 'bad argument' error and do nothing. '''Always check if this works with a function before using it in a script'''.\|1}}

	==Scripting custom functions with optional arguments==		==Scripting custom functions with optional arguments==
	Scripting functions with optional arguments is as easy as using ''if'' statements:		Scripting functions with optional arguments is as easy as using ''if'' statements:

Surge at 17:15, 21 October 2018

2018-10-21T17:15:24Z

← Older revision		Revision as of 17:15, 21 October 2018
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	end</syntaxhighlight>		end</syntaxhighlight>

			[[hu:Optional Arguments]]
	[[pl:Argumenty opcjonalne]]		[[pl:Argumenty opcjonalne]]
	[[Category:Scripting Concepts]]		[[Category:Scripting Concepts]]
	[[ru:Optional Arguments]]		[[ru:Optional Arguments]]
	[[de:Optionale Argumente]]		[[de:Optionale Argumente]]

AlexTMjugador at 10:35, 17 January 2016

2016-01-17T10:35:21Z

← Older revision		Revision as of 10:35, 17 January 2016
Line 24:		Line 24:

	And the result will be an Infernus rotated 180 degrees in the Z axis in the center of the map.		And the result will be an Infernus rotated 180 degrees in the Z axis in the center of the map.
	{{Warning\|There are some built-in MTA: SA functions that don't follow this convention, especially when ~~some~~ optional argument is closely related to another (e.g. color arguments in DX functions, and probably others): instead of replacing the ''nil'' value, they output a 'bad argument' error and do nothing. '''Always check if this works with a function before using it in a script'''.\|1}}		{{Warning\|There are some built-in MTA: SA functions that don't follow this convention, especially when an optional argument is closely related to another (e.g. color arguments in DX functions, and probably others): instead of replacing the ''nil'' value, they output a 'bad argument' error and do nothing. '''Always check if this works with a function before using it in a script'''.\|1}}
	==Scripting custom functions with optional arguments==		==Scripting custom functions with optional arguments==
	Scripting functions with optional arguments is as easy as using ''if'' statements:		Scripting functions with optional arguments is as easy as using ''if'' statements:

AlexTMjugador at 10:32, 17 January 2016

2016-01-17T10:32:47Z

← Older revision		Revision as of 10:32, 17 January 2016
Line 15:		Line 15:
	Optional argument are used just like normal arguments. The only difference is that they will default to a certain value if no provided (in other words, if optionalArgument == nil then optionalArgument = defaultValue).		Optional argument are used just like normal arguments. The only difference is that they will default to a certain value if no provided (in other words, if optionalArgument == nil then optionalArgument = defaultValue).

	One common problem to new scripters is when they want to provide only an optional argument, without setting the ones that are before it. Well, this is really simple to "fix". Normally, ~~you~~ can set ~~them~~ to ''[[nil]]'', so they will default to its corresponding values while ~~you are~~ still able to set the one ~~you~~ really ~~want~~ to. For example, if you want to only set the rotation in Z axis of the [[createVehicle]] function (and don't know that ''rx'' and ''ry'' defualt to zero):		One common problem to new scripters is when they want to provide only an optional argument, without setting the ones that are before it. Well, this is really simple to "fix". Normally, they can be set to ''[[nil]]'', so they will default to its corresponding values while the scripter is still able to set the one he really wants to. For example, if you want to only set the rotation in Z axis of the [[createVehicle]] function (and don't know that ''rx'' and ''ry'' defualt to zero):

	<syntaxhighlight lang="lua">vehicle createVehicle ( int model, float x, float y, float z, [ float rx, float ry, float rz ] )</syntaxhighlight>		<syntaxhighlight lang="lua">vehicle createVehicle ( int model, float x, float y, float z, [ float rx, float ry, float rz ] )</syntaxhighlight>

AlexTMjugador: Corrected some facts about the need of providing optional arguments which are before other (maybe OOP did change this?)

2016-01-17T10:30:41Z

Corrected some facts about the need of providing optional arguments which are before other (maybe OOP did change this?)

AlexTMjugador: Better explanation

2014-08-18T18:54:46Z

Better explanation

← Older revision		Revision as of 18:54, 18 August 2014
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	[[Optional ~~Arguments]]~~ are arguments ~~that are~~ passed to a function ~~but~~ are not required for the function to run. Often, ~~if you~~ do not ~~specify them, default values will be used instead~~.		'''Optional arguments''' are arguments which can be optionally passed to any Lua function, including MTA: SA built-in ones. They are not required for the function to run, and can be unset (value == ''[[nil]]''). Often, this kind of arguments do not make a huge difference in the behaviour of the function.

	~~When looking at~~ the ~~Syntax for an argument, Optional~~ arguments are ~~always enclosed~~ in ~~Square~~ brackets.		It's a Lua convention that the arguments written between square brackets are optional, so in this Wiki you can find functions with some arguments between square brackets too. That means they are optional and that providing them is not necessary.

	~~Example~~:		Let's take a look at this common function:

	<syntaxhighlight lang="lua">createVehicle ( int model, float x, float y, float z, [ float rx, float ry, float rz ] )</syntaxhighlight>		<syntaxhighlight lang="lua">vehicle createVehicle ( int model, float x, float y, float z, [ float rx, float ry, float rz ] )</syntaxhighlight>

	In this example, '''rx''', '''ry''', and '''rz''' are ~~[[Optional Arguments]]~~.		In this example, ''rx'', ''ry'', and ''rz'' are optional arguments, because they are between square brackets. They do not need to be provided to the function; it will default to no rotation in every axis. If provided, the function will use the rotations specified instead.

	==~~Using Optional Arguments~~==		==Why are optional arguments used?==
			More often than not, it's boring having to provide all the arguments of a certain function, especially if they are the same over and over again. The optional arguments allow the scripter to only pass the data that is really needed for his script, and that helps improving code readibility and size.

	~~[[Optional Arguments]] have one limitation. You cannot use any~~ optional arguments ~~unless ''all previous~~ arguments ~~are also supplied~~.''		==Use of the optional arguments==
			Optional argument are used just like normal arguments. The only difference is that they will default to a certain value if no provided (in other words, if optionalArgument == nil then optionalArgument = defaultValue).

	~~This means~~ that ~~in the previous example~~, ~~if you wanted~~ to ~~supply~~ ''~~'rz'~~'', you ~~would also need~~ to ~~supply~~ '''rx'''~~, and~~ '''ry''' ''~~in order~~.''		One common problem to new scripters is when you want to provide only an optional argument, without setting the ones that are before it. Well, this is really simple to "fix". You can set to ''[[nil]]'' the optional arguments before, so they will still default to its corresponding values while you are still able to set the one you really want to. For example, if you want to only set the rotation in Z axis of the [[createVehicle]] function (and don't know that ''rx'' and ''ry'' defualt to zero):

			<syntaxhighlight lang="lua">vehicle createVehicle ( int model, float x, float y, float z, [ float rx, float ry, float rz ] )</syntaxhighlight>

			You can use:

			<syntaxhighlight lang="lua">local myAwensomeVehicle = createVehicle( getVehicleModelFromName( "Infernus" ), 0, 0, 5, nil, nil, 180 )</syntaxhighlight>

			And the result will be an Infernus rotated 180 degrees in the center of the map.

			==Scripting custom functions with optional arguments==
			Scripting functions with optional arguments it's as easy as using ''if'' statements:

			<syntaxhighlight lang="lua">function aNotSoUsefulFunction( text )
			if type( text ) == "string" or type( text ) == "nil" then -- Check if correct arguments have been provided
			local realTextToOutput
			if text == nil then
			realTextToOutput = "I <3 optional arguments" -- If the text is nil (not specified), use a default one
			else
			realTextToOutput = text -- Use the text that the user specified if defined
			end
			outputChatBox( realTextToOutput ) -- Output the text
			end
			end</syntaxhighlight>

			You can also use [http://en.wikipedia.org/wiki/Short-circuit_evaluation short logic], if you prefer to:

			<syntaxhighlight lang="lua">function aNotSoUsefulFunction( text )
			local realTextToOutput = ( type( text ) == "string" or type( text ) == "nil" ) and ( type( text ) == "string" and text or "I <3 optional arguments" ) or nil
			if realTextToOutput then -- Check if there is something to output
			outputChatBox( realTextToOutput ) -- Output the text
			end
			end</syntaxhighlight>

	[[pl:Argumenty opcjonalne]]		[[pl:Argumenty opcjonalne]]

Leyynen: andere Sprache hinzugefügt

2012-08-21T11:42:03Z

andere Sprache hinzugefügt

← Older revision		Revision as of 11:42, 21 August 2012
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	[[Category:Scripting Concepts]]		[[Category:Scripting Concepts]]
	[[ru:Optional Arguments]]		[[ru:Optional Arguments]]
			[[de:Optionale Argumente]]

50p at 01:37, 12 August 2010

2010-08-12T01:37:22Z

← Older revision		Revision as of 01:37, 12 August 2010
Line 5:		Line 5:
	Example:		Example:

	<syntaxhighlight lang="lua">~~theVehicle =~~ createVehicle ( int model, float x, float y, float z, [ float rx, float ry, float rz ] )</syntaxhighlight>		<syntaxhighlight lang="lua">createVehicle ( int model, float x, float y, float z, [ float rx, float ry, float rz ] )</syntaxhighlight>

	In this example, '''rx''', '''ry''', and '''rz''' are [[Optional Arguments]].		In this example, '''rx''', '''ry''', and '''rz''' are [[Optional Arguments]].

Sebassje at 18:47, 11 August 2010

2010-08-11T18:47:27Z

← Older revision		Revision as of 18:47, 11 August 2010
Line 5:		Line 5:
	Example:		Example:

	<syntaxhighlight lang="lua">~~vehicle~~ = createVehicle ( model, x, y, z, [rx, ry, rz] )</syntaxhighlight>		<syntaxhighlight lang="lua">theVehicle = createVehicle ( int model, float x, float y, float z, [ float rx, float ry, float rz ] )</syntaxhighlight>

	In this example, '''rx''', '''ry''', and '''rz''' are [[Optional Arguments]].		In this example, '''rx''', '''ry''', and '''rz''' are [[Optional Arguments]].

← Older revision		Revision as of 10:30, 17 January 2016
Line 15:		Line 15:
	Optional argument are used just like normal arguments. The only difference is that they will default to a certain value if no provided (in other words, if optionalArgument == nil then optionalArgument = defaultValue).		Optional argument are used just like normal arguments. The only difference is that they will default to a certain value if no provided (in other words, if optionalArgument == nil then optionalArgument = defaultValue).

	One common problem to new scripters is when ~~you~~ want to provide only an optional argument, without setting the ones that are before it. Well, this is really simple to "fix". ~~You~~ can set to ''[[nil]]'' ~~the optional arguments before~~, so they will ~~still~~ default to its corresponding values while you are still able to set the one you really want to. For example, if you want to only set the rotation in Z axis of the [[createVehicle]] function (and don't know that ''rx'' and ''ry'' defualt to zero):		One common problem to new scripters is when they want to provide only an optional argument, without setting the ones that are before it. Well, this is really simple to "fix". Normally, you can set them to ''[[nil]]'', so they will default to its corresponding values while you are still able to set the one you really want to. For example, if you want to only set the rotation in Z axis of the [[createVehicle]] function (and don't know that ''rx'' and ''ry'' defualt to zero):

	<syntaxhighlight lang="lua">vehicle createVehicle ( int model, float x, float y, float z, [ float rx, float ry, float rz ] )</syntaxhighlight>		<syntaxhighlight lang="lua">vehicle createVehicle ( int model, float x, float y, float z, [ float rx, float ry, float rz ] )</syntaxhighlight>
Line 23:		Line 23:
	<syntaxhighlight lang="lua">local myAwensomeVehicle = createVehicle( getVehicleModelFromName( "Infernus" ), 0, 0, 5, nil, nil, 180 )</syntaxhighlight>		<syntaxhighlight lang="lua">local myAwensomeVehicle = createVehicle( getVehicleModelFromName( "Infernus" ), 0, 0, 5, nil, nil, 180 )</syntaxhighlight>

	And the result will be an Infernus rotated 180 degrees in the center of the map.		And the result will be an Infernus rotated 180 degrees in the Z axis in the center of the map.
			{{Warning\|There are some built-in MTA: SA functions that don't follow this convention, especially when some optional argument is closely related to another (e.g. color arguments in DX functions, and probably others): instead of replacing the ''nil'' value, they output a 'bad argument' error and do nothing. '''Always check if this works with a function before using it in a script'''.\|1}}
	==Scripting custom functions with optional arguments==		==Scripting custom functions with optional arguments==
	Scripting functions with optional arguments ~~it's~~ as easy as using ''if'' statements:		Scripting functions with optional arguments is as easy as using ''if'' statements:

	<syntaxhighlight lang="lua">function aNotSoUsefulFunction( text )		<syntaxhighlight lang="lua">function aNotSoUsefulFunction( text )
Line 40:		Line 40:
	end</syntaxhighlight>		end</syntaxhighlight>

	You can also use [http://en.wikipedia.org/wiki/Short-circuit_evaluation short ~~logic~~], if you prefer to:		You can also use [http://en.wikipedia.org/wiki/Short-circuit_evaluation short-circuit evaluation], if you prefer to:

	<syntaxhighlight lang="lua">function aNotSoUsefulFunction( text )		<syntaxhighlight lang="lua">function aNotSoUsefulFunction( text )