Difference between revisions of "Module:Yesno"

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(get arguments from the parent frame if the current frame doesn't have any)
(tweak logic to make it work like the actual template - the documentation was slightly wrong)
Line 1: Line 1:
 
local p = {}
 
local p = {}
+
 
 
function p.yesno(frame)
 
function p.yesno(frame)
+
 
 
     -- defaults
 
     -- defaults
 
     local retvals = {
 
     local retvals = {
Line 9: Line 9:
 
         ["¬"] = ""
 
         ["¬"] = ""
 
     }
 
     }
+
 
 
     -- 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.
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         end
 
         end
 
     end     
 
     end     
+
 
 
     val = args[1]
 
     val = args[1]
+
 
     -- According to the template docs, the input should be considered nil
+
     -- First deal with the case if val is nil, then deal with other cases.
    -- only when no params were provided. If any params at all were present,
+
     if val == nil then
    -- the value must be considered blank. A bit weird, if you ask me.
 
     if (val == nil and not any) or val == '¬' then
 
 
         return retvals['¬']
 
         return retvals['¬']
 
     end
 
     end
+
 
     val = (val or ''):lower()          -- Coerce to blank if nil; make lowercase.
+
     val = val:lower()          -- Coerce to blank if nil; make lowercase.
 
     val = val:match'^%s*(.*%S)' or ''  -- Trim whitespace.
 
     val = val:match'^%s*(.*%S)' or ''  -- Trim whitespace.
+
 
 
     if val == '' then
 
     if val == '' then
         return retvals['blank'] ~= nil and retvals['blank'] or retvals['no']
+
         return retvals['blank'] or retvals['no']
 
     elseif val == 'n' or val == 'no'  or val == '0' then
 
     elseif val == 'n' or val == 'no'  or val == '0' then
 
         return retvals['no']
 
         return retvals['no']
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     end
 
     end
 
end
 
end
+
 
 
return p
 
return p

Revision as of 10:18, 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]

    -- First deal with the case if val is nil, then deal with other cases.
    if val == nil then
        return retvals['¬']
    end

    val = val:lower()          -- Coerce to blank if nil; make lowercase.
    val = val:match'^%s*(.*%S)' or ''  -- Trim whitespace.

    if val == '' then
        return 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