Metatables & Rainmeter: Making editing from lua easy v5

[ailia]

Metatables are an extremely powerful lua tool that allow definition of what happens when a table is accessed or written to. Using them things like meters, measures and variables can be accessed 'directly' without having to write bangs or indirectly access individual elements from SKIN.

Example 1
Configuring disabled hyopthetical meter [Foo] in lua

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SKIN:GetMeter('Foo'):Enable()
SKIN:GetMeter('Foo'):SetX(10)
SKIN:GetMeter('Foo'):SetY(10)
SKIN:Bang('!SetOption','Foo','MeasureName','Bar')

Using Metatables

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meters['Foo'].Disabled=0
meters['Foo'].X=10
meters['Foo'].Y=10
meters['Foo'].MeasureName='Bar'

Alternative Syntax

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meters.Foo.Disabled=0
meters.Foo.X=10
meters.Foo.Y=10
meters.Foo.MeasureName='Bar'

Example 2
Updating static text meter [Foo] that has UpdateDivider=-1

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SKIN:Bang('!SetOption', 'Foo', 'Text', 'Bar')
SKIN:Bang('!UpdateMeter', 'Foo')

Using Metatables

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meters.Foo.Text='Bar'
meters.Foo.UpdateMeter()

Example 3
Accessing Meter attributes, Measure and Variable values from Lua

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SKIN:GetMeasure('Foo1'):GetOption('MeasureName')
-- As a string
SKIN:GetMeasure('Foo2'):GetStringValue()
-- As a number
SKIN:GetMeasure('Foo2'):GetValue()
SKIN:GetVariable('Foo3')

Using Metatables

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measures.Foo1.MeasureName
-- As a string
measures.Foo2.GetStringValue()
-- As a number
measures.Foo2.GetValue()
variables.Foo3

Lua Rainmeter Metatables v5
Probably the last version unless errors are discovered.

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local ms = {__index = function(tb,key) if key == 'UpdateMeasure' then return function() SKIN:Bang('!UpdateMeasure',tb.__sectionname) end elseif tb.__section[key] then return function(...) return tb.__section[key](tb.__section,...) end else return (tb.__section.GetNumberOption and tb.__section:GetNumberOption(key,nil)) or tb.__section:GetOption(key) end end, __newindex = function(tb,key,value) SKIN:Bang('!SetOption',tb.__sectionname,key,value) end}
sections,variables = {__index = function(tb,key) sections[key]={} sections[key].__section, sections[key].__sectionname = SKIN:GetMeasure(key), key setmetatable(sections[key],ms) return sections[key] end},{__index = function(tb,key) return SKIN:GetVariable(key) end, __newindex = function(tb,key,value) SKIN:Bang('!SetVariable',key,value) end}
setmetatable(variables,variables)
setmetatable(sections,sections)
meters, measures = sections, sections

Lua Rainmeter Metatables v4
Fixed inheritance of Meter functions - Note changes to example 3 if using previous Versions

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local metameters, metameter, metameasures, metameasure, metavariables = {},{},{},{},{}
metameter.__newindex = function(tb,key,value) SKIN:Bang('!SetOption',tb.__metername,key,value) end
metameter.__index = function(tb,key)
	if tb.__meter[key] then return function(...) return tb.__meter[key](tb.__meter,...) end
	else return tb.__meter:GetOption(key) end
end
metameters.__index = function(tb,key)
	meters[key]={} meters[key].__meter, meters[key].__metername = SKIN:GetMeter(key), key
	setmetatable(meters[key],metameter)
	return meters[key]
end
metameasure.__newindex = function(tb,key,value) SKIN:Bang('!SetOption',tb.__measurename,key,value) end
metameasure.__index = function(tb,key)
	if key == 'UpdateMeasure' then return function() SKIN:Bang('!UpdateMeasure',tb.__measurename) end
	elseif tb.__measure[key] then return function(...) return tb.__measure[key](tb.__measure,...) end
	else return tb.__measure:GetNumberOption(key,nil) or tb.__measure:GetOption(key) end
end
metameasures.__index = function(tb,key)
	measures[key]={} measures[key].__measure, measures[key].__measurename = SKIN:GetMeasure(key), key
	setmetatable(measures[key],metameasure)
	return measures[key]
end
metavariables.__index = function(tb,key) return SKIN:GetVariable(key) end
metavariables.__newindex = function(tb,key,value) SKIN:Bang('!SetVariable',key,value) end
meters,measures,variables = {},{},{}
setmetatable(meters,metameters) setmetatable(measures,metameasures) setmetatable(variables,metavariables)

Lua Rainmeter Metatables v3
Removed nested local metatables, ram usage down a lot

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local metameters = {}
local metameter = {}
metameter.__newindex = function(tb,key,value)
	SKIN:Bang('!SetOption',tb.__metername,key,value)
end
metameter.__index = function(tb,key)
	return tb.__meter:GetOption(key)
end
metameters.__index = function(tb,key)
	meters[key]={}
	meters[key].__meter = SKIN:GetMeter(key)
	meters[key].__metername = key
	setmetatable(meters[key],metameter)
	return meters[key]
end
meters = {}
setmetatable(meters,metameters)

local metameasures = {}
local metameasure = {}
metameasure.__newindex = function(tb,key,value)
	SKIN:Bang('!SetOption',tb.__measurename,key,value)
end
metameasure.__index = function(tb,key)
	if key == 'String' then
		return tb.__measure:GetStringValue()
	elseif key == 'Value' then
		return tonumber(tb.__measure:GetValue())
	elseif key == 'MinValue' then
		return tonumber(tb.__measure:GetMinValue())
	elseif key == 'MaxValue' then
		return tonumber(tb.__measure:GetMaxValue())
	elseif key == 'UpdateMeasure' then
		return function() SKIN:Bang('!UpdateMeasure',tb.__measurename) end
	else
		local t = tb.__measure:GetNumberOption(key,nil)
		return t or tb.__measure:GetOption(key)
	end
end
metameasures.__index = function(tb,key)
	measures[key]={}
	measures[key].__measure = SKIN:GetMeasure(key)
	measures[key].__measurename = key
	setmetatable(measures[key],metameasure)
	return measures[key]
end
measures = {}
setmetatable(measures,metameasures)

local metavariables = {}
metavariables.__index = function(tb,key)
	return SKIN:GetVariable(key)
end
metavariables.__newindex = function(tb,key,value)
	SKIN:Bang('!SetVariable',key,value)
end
variables = {}
setmetatable(variables,metavariables)

Lua Rainmeter Metatables v2

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local metameters = {}
metameters.__index = function(tb,key)
	meters[key]={}
	local metameter = {}
	metameter.__newindex = function(tb2,key2,value2)
		SKIN:Bang('!SetOption',key,key2,value2)
	end
	metameter.__index = function(tb2,key2)
		return SKIN:GetMeter(key):GetOption(key2)
	end
	setmetatable(meters[key],metameter)
	return meters[key]
end
meters = {}
setmetatable(meters,metameters)

local metameasures = {}
metameasures.__index = function(tb,key)
	measures[key]={}
	local metameasure = {}
	metameasure.__newindex = function(tb2,key2,value2)
		SKIN:Bang('!SetOption',key,key2,value2)
	end
	metameasure.__index = function(tb2,key2)
		if key2 == 'String' then
			return SKIN:GetMeasure(key):GetStringValue()
		elseif key2 == 'Value' then
			return tonumber(SKIN:GetMeasure(key):GetValue())
		elseif key2 == 'MinValue' then
			return tonumber(SKIN:GetMeasure(key):GetMinValue())
		elseif key2 == 'MaxValue' then
			return tonumber(SKIN:GetMeasure(key):GetMaxValue())
		elseif key2 == 'UpdateMeasure' then
			return function() SKIN:Bang('!UpdateMeasure',key) end
		else
			local t = SKIN:GetMeasure(key):GetNumberOption(key2,nil)
			return t or SKIN:GetMeasure(key):GetOption(key2)
		end
	end
	setmetatable(measures[key],metameasure)
	return measures[key]
end
measures = {}
setmetatable(measures,metameasures)

local metavariables = {}
metavariables.__index = function(tb,key)
	return SKIN:GetVariable(key)
end
metavariables.__newindex = function(tb,key,value)
	SKIN:Bang('!SetVariable',key,value)
end
variables = {}
setmetatable(variables,metavariables)

Lua Rainmeter Metatables v1

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local metameters = {}
metameters.__index = function(tb,key)
	meters[key]={}
	local metameter = {}
	metameter.__newindex = function(tb2,key2,value2)
		SKIN:Bang('!SetOption',key,key2,value2)
	end
	metameter.__index = function(tb2,key2)
		return tonumber(SKIN:GetMeter(key):GetOption(key2))
	end
	setmetatable(meters[key],metameter)
	return meters[key]
end
meters = {}
setmetatable(meters,metameters)

local metameasures = {}
metameasures.__index = function(tb,key)
	measures[key]={}
	local metameasure = {}
	metameasure.__newindex = function(tb2,key2,value2)
		SKIN:Bang('!SetOption',key,key2,value2)
	end
	metameasure.__index = function(tb2,key2)
		if key2 == 'String' then
			return SKIN:GetMeasure(key):GetStringValue()
		elseif key2 == 'Value' then
			return tonumber(SKIN:GetMeasure(key):GetValue())
		elseif key2 == 'MinValue' then
			return tonumber(SKIN:GetMeasure(key):GetMinValue())
		elseif key2 == 'MaxValue' then
			return tonumber(SKIN:GetMeasure(key):GetMaxValue())
		elseif key2 == 'UpdateMeasure' then
			return function() SKIN:Bang('!UpdateMeasure',key) end
		else
			return tonumber(SKIN:GetMeasure(key):GetOption(key2))
		end
	end
	setmetatable(measures[key],metameasure)
	return measures[key]
end
measures = {}
setmetatable(measures,metameasures)

local metavariables = {}
metavariables.__index = function(tb,key)
	return SKIN:GetVariable(key)
end
metavariables.__newindex = function(tb,key,value)
	SKIN:Bang('!SetVariable',key,value)
end
variables = {}
setmetatable(variables,metavariables)

[MerlinTheRed]

This is a really interesting and flexible way of doing some kind of object orientation in Lua. I wonder if it gets confusing if you don't do it right. Thanks for pointing out this Lua feature. And thanks for sharing your code. I assume one should put this in the Initialize() function of a script?

[ailia]

Yep, not much else to it.