Module:Yesno

From Dota 2 Wiki
Jump to: navigation, search

Documentation for Module:Yesno Jump to code ↴ [ edit | purge ]

Wikipedia icon.png
Documentation for this template is available at Module:Yesno on Wikipedia.

This module provides a consistent interface for processing boolean or boolean-style string input. While Lua allows the true and false boolean values, wikicode templates can only express boolean values through strings such as "yes", "no", etc. This module processes these kinds of strings and turns them into boolean input for Lua to process. It also returns nil values as nil, to allow for distinctions between nil and false. The module also accepts other Lua structures as input, i.e. booleans, numbers, tables, and functions. If it is passed input that it does not recognise as boolean or nil, it is possible to specify a default value to return.

Syntax[edit]

yesno(value, default)

value is the value to be tested. Boolean input or boolean-style input (see below) always evaluates to either true or false, and nil always evaluates to nil. Other values evaluate to default.

Usage[edit]

First, load the module. Note that it can only be loaded from other Lua modules, not from normal wiki pages. For normal wiki pages you can use {{yesno}} instead.

local yesno = require('Module:Yesno')

Some input values always return true, and some always return false. nil values always return nil.

-- These always return true:
yesno('yes')
yesno('y')
yesno('true')
yesno('t')
yesno('1')
yesno(1)
yesno(true)

-- These always return false:
yesno('no')
yesno('n')
yesno('false')
yesno('f')
yesno('0')
yesno(0)
yesno(false)

-- A nil value always returns nil:
yesno(nil)

String values are converted to lower case before they are matched:

-- These always return true:
yesno('Yes')
yesno('YES')
yesno('yEs')
yesno('Y')
yesno('tRuE')

-- These always return false:
yesno('No')
yesno('NO')
yesno('nO')
yesno('N')
yesno('fALsE')

You can specify a default value if yesno receives input other than that listed above. If you don't supply a default, the module will return nil for these inputs.

-- These return nil:
yesno('foo')
yesno({})
yesno(5)
yesno(function() return 'This is a function.' end)

-- These return true:
yesno('foo', true)
yesno({}, true)
yesno(5, true)
yesno(function() return 'This is a function.' end, true)

-- These return "bar":
yesno('foo', 'bar')
yesno({}, 'bar')
yesno(5, 'bar')
yesno(function() return 'This is a function.' end, 'bar')

Note that the blank string also functions this way:

yesno('')        -- Returns nil.
yesno('', true)  -- Returns true.
yesno('', 'bar') -- Returns "bar".

Although the blank string usually evaluates to false in wikitext, it evaluates to true in Lua. This module prefers the Lua behaviour over the wikitext behaviour. If treating the blank string as false is important for your module, you will need to remove blank arguments at an earlier stage of processing.

Tests[edit]

YesY All tests passed.

Name Expected Actual
YesY testBlankStringDefaultSet
YesY testBlankStringNoDefault
YesY testFalse
YesY testFalseDefaultPrecedence
YesY testFalseText
YesY testFalseTextCaps
YesY testFalseTextDefaultPrecedence
YesY testFunctionDefaultSet
YesY testFunctionNoDefault
YesY testN
YesY testNCaps
YesY testNDefaultPrecedence
YesY testNil
YesY testNilDefaultPrecedence
YesY testNo
YesY testNoCaps
YesY testNoDefaultPrecedence
YesY testNumberDefaultSet
YesY testNumberNoDefault
YesY testOne
YesY testOneDefaultPrecedence
YesY testOneText
YesY testOneTextConversion
YesY testOneTextDefaultPrecedence
YesY testStringDefaultSet
YesY testStringNoDefault
YesY testTableDefaultSet
YesY testTableNoDefault
YesY testTrue
YesY testTrueDefaultPrecedence
YesY testTrueText
YesY testTrueTextCaps
YesY testTrueTextDefaultPrecedence
YesY testY
YesY testYCaps
YesY testYDefaultPrecedence
YesY testYes
YesY testYesCaps
YesY testYesDefaultPrecedence
YesY testZero
YesY testZeroDefaultPrecedence
YesY testZeroText
YesY testZeroTextConversion
YesY testZeroTextDefaultPrecedence


-- Function allowing for consistent treatment of boolean-like wikitext input.
-- It works similarly to the template {{yesno}}.

return function (val, default)
	-- If your wiki uses non-ascii characters for any of "yes", "no", etc., you
	-- should replace "val:lower()" with "mw.ustring.lower(val)" in the
	-- following line.
	val = type(val) == 'string' and val:lower() or val
	if val == nil then
		return nil
	elseif val == true 
		or val == 'yes'
		or val == 'y'
		or val == 'true'
		or val == 't'
		or val == 'on'
		or tonumber(val) == 1
	then
		return true
	elseif val == false
		or val == 'no'
		or val == 'n'
		or val == 'false'
		or val == 'f'
		or val == 'off'
		or tonumber(val) == 0
	then
		return false
	else
		return default
	end
end