WoW:UI best practices - Revision history

Move page script: Move page script moved page UI best practices to WoW:UI best practices without leaving a redirect

2023-08-15T04:49:01Z

Move page script moved page UI best practices to UI best practices without leaving a redirect

← Older revision

Revision as of 04:49, 15 August 2023

Bear at 08:02, 18 September 2013

2013-09-18T08:02:20Z

← Older revision		Revision as of 08:02, 18 September 2013
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	{{~~wowapi}}{{tocright~~}}		{{uitech}}

	With the low barrier to entry, writing mods has become very popular. While this has greatly benefited the WoW community, it does have a dark side. There are idiosyncrasies in both the [[Lua\|Lua language]] and the [[World of Warcraft API]] that many authors overlook. This can lead to poorly written programs as measured by performance, memory usage, interference with other addons and the default UI, etc. The techniques gathering on this page will help help addon authors, experienced and otherwise, make the most out of WoW's environment safely and efficiently.		With the low barrier to entry, writing mods has become very popular. While this has greatly benefited the WoW community, it does have a dark side. There are idiosyncrasies in both the [[Lua\|Lua language]] and the [[World of Warcraft API]] that many authors overlook. This can lead to poorly written programs as measured by performance, memory usage, interference with other addons and the default UI, etc. The techniques gathering on this page will help help addon authors, experienced and otherwise, make the most out of WoW's environment safely and efficiently.
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	MyEventHandler()		MyEventHandler()
	</OnEvent>		</OnEvent>

	Old Lua		Old Lua
	function MyEventHandler()		function MyEventHandler()
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	MyEventHandler(self, event, ...)		MyEventHandler(self, event, ...)
	</OnEvent>		</OnEvent>

	New Lua		New Lua
	function MyEventHandler(frame, event, firstArg, secondArg)		function MyEventHandler(frame, event, firstArg, secondArg)
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	<OnEvent function="MyEventHandler" />		<OnEvent function="MyEventHandler" />
	This has the advantage of resulting in a reference call, without an anonymous code block calling a global function.		This has the advantage of resulting in a reference call, without an anonymous code block calling a global function.

	==== Lua only ====		==== Lua only ====

WoWWiki>SinusPi: added OnEvent function="..." syntax

2010-02-17T02:02:27Z

added OnEvent function="..." syntax

← Older revision		Revision as of 02:02, 17 February 2010
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	end		end

			Even Newer XML
			<OnEvent function="MyEventHandler" />
			This has the advantage of resulting in a reference call, without an anonymous code block calling a global function.

	==== Lua only ====		==== Lua only ====

WoWWiki>Egingell: /* Order of Operations */

2009-01-27T00:10:40Z

Order of Operations

← Older revision		Revision as of 00:10, 27 January 2009
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	==== Order of Operations ====		==== Order of Operations ====

	Lua, like ~~all~~ other programming languages, executes expressions from left to right starting from the innermost parenthesis to the outermost. This allows for un-nesting of IF blocks.		Lua, like many other programming languages, executes expressions from left to right starting from the innermost parenthesis to the outermost. This allows for un-nesting of IF blocks.

	-- This:		-- This:
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	end		end

	: ~~''Actually, there~~ are several programming languages that ~~does~~ not read left to right, eg. Joy, Factor, J and K etc. Others - like Haskell - can be used both ways. There are even languages that are multi-dimensional! While many of these are mainly ~~academical~~, they are not ~~esoterical~~ languages made to be weird, but rather based on recent theories and ideas in computer science. ~~/rant'' [[User:Kopokopolo\|Kopokopolo]] ([[User talk:Kopokopolo\|talk]]) 12:40, 26 January 2009 (UTC)~~		Note: There are several programming languages that do not read left to right (eg. Joy, Factor, J and K, etc.). Others - like Haskell - can be used both ways. There are even languages that are multi-dimensional. While many of these are mainly academic, they are not esoteric languages made to be weird, but rather based on recent theories and ideas in computer science.

	==== Lazy Coding ====		==== Lazy Coding ====

WoWWiki>Kopokopolo: rant on order of operations

2009-01-26T12:40:38Z

rant on order of operations

← Older revision		Revision as of 12:40, 26 January 2009
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	DoStuff()		DoStuff()
	end		end

			: ''Actually, there are several programming languages that does not read left to right, eg. Joy, Factor, J and K etc. Others - like Haskell - can be used both ways. There are even languages that are multi-dimensional! While many of these are mainly academical, they are not esoterical languages made to be weird, but rather based on recent theories and ideas in computer science. /rant'' [[User:Kopokopolo\|Kopokopolo]] ([[User talk:Kopokopolo\|talk]]) 12:40, 26 January 2009 (UTC)

	==== Lazy Coding ====		==== Lazy Coding ====

WoWWiki>NefariousN: /* Lazy Coding */

2008-09-11T05:48:43Z

Lazy Coding

← Older revision		Revision as of 05:48, 11 September 2008
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	One stumbling block for Lua programmers coming from other languages is the fact that all variables are global unless specified otherwise. Many times, the use of global variables is necessary: saved variables are created via the global environment; all API functions and UI frames are in the global namespace. However, globals come at a cost of both performance, and naming conflicts.		One stumbling block for Lua programmers coming from other languages is the fact that all variables are global unless specified otherwise. Many times, the use of global variables is necessary: saved variables are created via the global environment; all API functions and UI frames are in the global namespace. However, globals come at a cost of both performance, and naming conflicts.

	Globals ~~in Lua~~ are ~~actually fields in a table called _G. In order~~ to access a global ~~variable~~, Lua ~~internally translates~~ the ~~variable name~~ to ~~_G["variable name"]~~. Local variables, on the other hand, are stored on a stack~~. Stack access is always faster than indexing a table~~. In code where performance is important (for instance an [[UIHANDLER OnUpdate\|OnUpdate handler]]), it's often beneficial to create a local alias to a global function:		Globals are inefficient to access compared to locals. Whenever a global is accessed, Lua has to call the internal equivalent of getfenv() to figure out where to retrieve the global from. Local variables, on the other hand, are stored on a stack. In code where performance is important (for instance an [[UIHANDLER OnUpdate\|OnUpdate handler]]), it's often beneficial to create a local alias to a global function:

	local Foo = Foo		local Foo = Foo
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	DoStuff()		DoStuff()
	end		end
	if foo~~[bar]~~ and foo[bar] == 5 then -- will not throw an error		if foo and foo[bar] == 5 then -- will not throw an error
	DoStuff()		DoStuff()
	end		end

WoWWiki>KirkBot: Typo fixing using AWB

2008-08-07T21:49:08Z

Typo fixing using AWB

← Older revision		Revision as of 21:49, 7 August 2008
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	One stumbling block for Lua programmers coming from other languages is the fact that all variables are global unless specified otherwise. Many times, the use of global variables is necessary: saved variables are created via the global environment; all API functions and UI frames are in the global namespace. However, globals come at a cost of both performance, and naming conflicts.		One stumbling block for Lua programmers coming from other languages is the fact that all variables are global unless specified otherwise. Many times, the use of global variables is necessary: saved variables are created via the global environment; all API functions and UI frames are in the global namespace. However, globals come at a cost of both performance, and naming conflicts.

	Globals in Lua are actually fields in a table called _G. In order to access a global variable, Lua internally translates the variable name to _G["variable name"]. Local variables, on the other hand, are stored on a stack. Stack access is always faster than indexing a table. In code where performance is important (for instance an [[~~UIHANDLER_OnUpdate~~\|OnUpdate handler]]), it's often beneficial to create a local alias to a global function:		Globals in Lua are actually fields in a table called _G. In order to access a global variable, Lua internally translates the variable name to _G["variable name"]. Local variables, on the other hand, are stored on a stack. Stack access is always faster than indexing a table. In code where performance is important (for instance an [[UIHANDLER OnUpdate\|OnUpdate handler]]), it's often beneficial to create a local alias to a global function:

	local Foo = Foo		local Foo = Foo
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	=== Hook functions safely ===		=== Hook functions safely ===

	See also: [[HOWTO:~~_Hook_functions_in_a_safer_way~~]]		See also: [[HOWTO: Hook functions in a safer way]]

	You should do your best to write your addon in such a way that you don't need to hook functions. Even when it is necessary, most of the time [[~~API_hooksecurefunc~~\|hooksecurefunc]] is sufficient. However, there are occasional cases where "traditional" hooking must be used. When you do, remember to pass all parameters and return all results. Example:		You should do your best to write your addon in such a way that you don't need to hook functions. Even when it is necessary, most of the time [[API hooksecurefunc\|hooksecurefunc]] is sufficient. However, there are occasional cases where "traditional" hooking must be used. When you do, remember to pass all parameters and return all results. Example:

	local OrigFunc = Func		local OrigFunc = Func
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	=== Use local event handler parameters ===		=== Use local event handler parameters ===

	With the introduction of WoW 2.0, [[~~Widget_Handlers~~\|widget event handlers]] now provide local parameters. As mentioned in [[#Use_local_variables\|a previous section]], accessing local values is more efficient than accessing globals. Here are a few examples of the old way and how they should be implemented now:		With the introduction of WoW 2.0, [[Widget Handlers\|widget event handlers]] now provide local parameters. As mentioned in [[#Use_local_variables\|a previous section]], accessing local values is more efficient than accessing globals. Here are a few examples of the old way and how they should be implemented now:

	==== Code directly in XML ====		==== Code directly in XML ====

WoWWiki>Charibot: catfix

2008-07-07T18:38:26Z

catfix

← Older revision		Revision as of 18:38, 7 July 2008
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	end		end
	end)		end)
	[[Category:Interface ~~Customization~~]]		[[Category:Interface customization]]

WoWWiki>Pcj at 15:13, 8 March 2008

2008-03-08T15:13:06Z

← Older revision		Revision as of 15:13, 8 March 2008
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	{{wowapi~~}}{{breadcrumb1\|Interface Customization~~}}{{tocright}}		{{wowapi}}{{tocright}}

	With the low barrier to entry, writing mods has become very popular. While this has greatly benefited the WoW community, it does have a dark side. There are idiosyncrasies in both the [[Lua\|Lua language]] and the [[World of Warcraft API]] that many authors overlook. This can lead to poorly written programs as measured by performance, memory usage, interference with other addons and the default UI, etc. The techniques gathering on this page will help help addon authors, experienced and otherwise, make the most out of WoW's environment safely and efficiently.		With the low barrier to entry, writing mods has become very popular. While this has greatly benefited the WoW community, it does have a dark side. There are idiosyncrasies in both the [[Lua\|Lua language]] and the [[World of Warcraft API]] that many authors overlook. This can lead to poorly written programs as measured by performance, memory usage, interference with other addons and the default UI, etc. The techniques gathering on this page will help help addon authors, experienced and otherwise, make the most out of WoW's environment safely and efficiently.

WoWWiki>Egingell: I appologize if this is not the proper place. UI_best_practices#Order of Operations, UI_best_practices#Lazy Coding. Corrected terminology. UI_best_practices#Short-Circuiting

2008-02-22T11:27:37Z

I appologize if this is not the proper place. UI_best_practices#Order of Operations, UI_best_practices#Lazy Coding. Corrected terminology. UI_best_practices#Short-Circuiting

@@ Line 71: / Line 71: @@
   end
-==== Shortcut evaluation ====
+==== Short-Circuiting ====
-Lua uses shortcut evaluation of conditionals. This means it only evaluates enough of the condition to know for certain whether it's true or false. In the case of or, the whole condition is known to be true as soon as one operand is true. For and, the whole condition is known to be false as soon as one operand is false. You can take advantage of this to add a bit of efficiency:
+Lua uses short-circuiting of conditionals. This means it only evaluates enough of the condition from left to right to know for certain whether it's true or false. In the case of "or", the whole condition is known to be true as soon as one operand is true. For "and", the whole condition is known to be false as soon as one operand is false. You can take advantage of this to add a bit of efficiency:
   if Fast() or Slow() then
@@ Line 82: / Line 82: @@
       DoStuff()
   end
 === Minimize use of throw-away tables ===
@@ Line 113: / Line 153: @@
       end
   </OnEvent>
 ==== XML calling Lua function ====