Difference between revisions of "Module:Yesno"
(Add inline comments) |
(get arguments from the parent frame if the current frame doesn't have any) |
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Line 1: | Line 1: | ||
local p = {} | local p = {} | ||
− | function p.yesno( frame ) | + | function p.yesno(frame) |
-- defaults | -- defaults | ||
Line 12: | Line 12: | ||
-- Allow arguments to override defaults. | -- Allow arguments to override defaults. | ||
-- 'any' tracks the presence of any arguments at all. | -- 'any' tracks the presence of any arguments at all. | ||
+ | local args = frame.args | ||
local any = false | local any = false | ||
− | for k,v in pairs( | + | for k,v in pairs(args) do |
any = true | any = true | ||
retvals[k] = v | retvals[k] = v | ||
end | end | ||
+ | -- If there are no arguments, try and get them from the parent frame. | ||
+ | if any == false then | ||
+ | local pframe = frame:getParent() | ||
+ | args = pframe.args | ||
+ | for k,v in pairs(args) do | ||
+ | any = true | ||
+ | retvals[k] = v | ||
+ | end | ||
+ | end | ||
− | val = | + | val = args[1] |
-- According to the template docs, the input should be considered nil | -- According to the template docs, the input should be considered nil |
Revision as of 08:35, 23 March 2013
Lua error in Module:Message_box at line 171: attempt to call upvalue 'yesno' (a table value).
Lua error in Module:Message_box at line 171: attempt to call upvalue 'yesno' (a table value).Lua error in Module:Category_handler at line 76: attempt to call upvalue 'yesno' (a table value).
Lua error in Module:Message_box at line 171: attempt to call upvalue 'yesno' (a table value).
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
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
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.
local p = {}
function p.yesno(frame)
-- defaults
local retvals = {
yes = "yes",
no = "",
["¬"] = ""
}
-- Allow arguments to override defaults.
-- 'any' tracks the presence of any arguments at all.
local args = frame.args
local any = false
for k,v in pairs(args) do
any = true
retvals[k] = v
end
-- If there are no arguments, try and get them from the parent frame.
if any == false then
local pframe = frame:getParent()
args = pframe.args
for k,v in pairs(args) do
any = true
retvals[k] = v
end
end
val = args[1]
-- According to the template docs, the input should be considered nil
-- only when no params were provided. If any params at all were present,
-- the value must be considered blank. A bit weird, if you ask me.
if (val == nil and not any) or val == '¬' then
return retvals['¬']
end
val = (val or ''):lower() -- Coerce to blank if nil; make lowercase.
val = val:match'^%s*(.*%S)' or '' -- Trim whitespace.
if val == '' then
return retvals['blank'] ~= nil and retvals['blank'] or retvals['no']
elseif val == 'n' or val == 'no' or val == '0' then
return retvals['no']
elseif val == 'y' or val == 'yes' or val == '1' or retvals['def'] == nil then
return retvals['yes']
else
return retvals['def']
end
end
return p