Module:Yesno

मॉड्यूल बिबरनलेख[देखीं] [संपादन करीं] [इतिहास देखीं] [रिफ्रेश करीं]

This module provides a consistent interface for processing boolean or boolean-style string input. While Lua allows thetrueandfalseboolean 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 returnsnilvalues asnil,to allow for distinctions betweennilandfalse.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 ornil,it is possible to specify a default value to return.

Syntax

yesno(value,default)

valueis the value to be tested. Boolean input or boolean-style input (see below) always evaluates to eithertrueorfalse,andnilalways evaluates tonil.Other values evaluate todefault.

Usage

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.

localyesno=require('Module:Yesno')

Some input values always returntrue,and some always returnfalse.nilvalues always returnnil.

-- These always return true:
yesno('yes')
yesno('y')
yesno('true')
yesno('1')
yesno(1)
yesno(true)

-- These always return false:
yesno('no')
yesno('n')
yesno('false')
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 returnnilfor 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.

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

returnfunction(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'andval:lower()orval
ifval==nilthen
returnnil
elseifval==true
orval=='yes'
orval=='y'
orval=='true'
orval=='t'
orval=='on'
ortonumber(val)==1
then
returntrue
elseifval==false
orval=='no'
orval=='n'
orval=='false'
orval=='f'
orval=='off'
ortonumber(val)==0
then
returnfalse
else
returndefault
end
end