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Module:Namespace detect

Permanently protected module
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This is an old revision of this page, as edited by Mr. Stradivarius (talk | contribs) at 14:10, 24 June 2013 (undo - on second thoughts, these failure modes are pretty arbitrary (bad titles actually default to "talk"), so changing them to both default to "other" is probably for the best). The present address (URL) is a permanent link to this revision, which may differ significantly from the current revision.

----------------------------------------------------------------------
--                                                                  --
--                        NAMESPACE DETECT                          --
--                                                                  --
--      This module implements the {{namespace detect}} template    --
--      in Lua, with a few improvements: all namespaces and all     --
--      namespace aliases are supported, and namespace names are    --
--      detected automatically for the local wiki. Function names   --
--      can be configured for different wikis by altering the       --
--      values in the "cfg" table.                                  --
--                                                                  --
----------------------------------------------------------------------

----------------------------------------------------------------------
--                      Configuration data                          --
--      Language-specific parameter names can be set here.          --
----------------------------------------------------------------------

local cfg = {}

-- The name for the parameter to display content for the main namespace:
cfg.main = 'main'

-- The name for the parameter to display content in talk namespaces:
cfg.talk = 'talk'

-- The name for the parameter to display content for "other" namespaces
-- (namespaces for which parameters have not been specified, or for when
-- cfg.demospace is set to cfg.other):
cfg.other = 'other'

-- The name for the parameter to set a demonstration namespace:
cfg.demospace = 'demospace'

-- The name for the parameter to set a specific page to compare:
cfg.page = 'page'

-- The header for the namespace column in the wikitable containing the 
-- list of possible subject-space parameters.
cfg.wikitableNamespaceHeader = 'Namespace'

-- The header for the wikitable containing the list of possible
-- subject-space parameters.
cfg.wikitableAliasesHeader = 'Aliases'

----------------------------------------------------------------------
--                     End configuration data                       --
----------------------------------------------------------------------

-- Specify variables available to the whole module
local p = {}
local args = {}

-- Get the page object. This will return the page object for the page
-- specified, or nil if there are errors in the title or if the
-- expensive function count has been exceeded.
local function getPageObject()
    -- Get the title object for args.page if it is specified. Otherwise
    -- get the title object for the current page.
    if args[cfg.page] then
        -- Get the page object, passing the function through pcall 
        -- in case we are over the expensive function count limit.
        local noError, pageObject = pcall(mw.title.new, args[cfg.page])
        if not noError then
            return nil
        else
            return pageObject
        end
    else
        return mw.title.getCurrentTitle()
    end    
end

-- Detects the namespace for a page object.
local function detectNamespace(pageObject)
    if pageObject.isTalkPage then
        -- Returns the value of cfg.talk or the local "Talk" namespace name. 
        return cfg.talk or mw.site.namespaces[1].name
    else
        return pageObject.nsText
    end
end

-- Gets the namespace name to compare to the arguments. The returned value
-- is lower-case.
local function getNamespace()
    local ret
    if args[cfg.demospace] then
        -- Handle "demospace = main" properly.
        if mw.ustring.lower( args[cfg.demospace] ) == cfg.main then
            ret = mw.site.namespaces[0].name
        else
            ret = args[cfg.demospace]
        end
    else
        local pageObject = getPageObject()
        if pageObject then
            ret = detectNamespace( getPageObject() )
        else
            return nil -- return nil if the page object doesn't exist.
        end
    end
    return mw.ustring.lower(ret)
end

-- Compare the namespace found with the parameters that have been
-- specified, and return content of the appropriate parameter.
local function compare()
    local namespace = getNamespace()
    
    -- First, compare mainspace parameters.
    if namespace == mw.site.namespaces[0].name and args[cfg.main] then
        return args[cfg.main]
    end
    
    -- Next, compare parameters for non-main namespaces.
    for nsid, ns in pairs( mw.site.namespaces ) do
        local nsname = mw.ustring.lower( ns.name )
        local canonicalName = mw.ustring.lower( ns.canonicalName )
        -- Check the namespace, and ignore main namespace values.
        if nsid ~= 0 and nsname == namespace then
            -- Check local namespace name.
            if args[nsname] then
                return args[nsname]
            -- Check canonical namespace name.
            elseif args[canonicalName] then
                return args[canonicalName]
            else
                -- Check alias names.
                for _, alias in ipairs( ns.aliases ) do
                    local aliasArg = args[ mw.ustring.lower( alias ) ]
                    if aliasArg then
                        return aliasArg
                    end
                end
            end
        end
    end
    
    -- Finally, return parameters for other namespaces. This happens if
    -- there was no text specified for the namespace that was detected
    -- or if the demospace parameter is not a valid namespace. Note that
    -- the parameter for the detected namespace must be completely
    -- absent for this to happen, not merely blank.
    if args[cfg.other] then
        return args[cfg.other]
    end
end

-- Process the arguments.
function p.main(frame)
    -- If called via #invoke, use the args passed into the invoking
    -- template, or the args passed to #invoke if any exist. Otherwise
    -- assume args are being passed directly in.
    local origArgs
    if frame == mw.getCurrentFrame() then
        origArgs = frame:getParent().args
        for k, v in pairs( frame.args ) do
            origArgs = frame.args
            break
        end
    else
        origArgs = frame
    end
    
    -- Trim whitespace and remove blank arguments for demospace and 
    -- page parameters.
    for k, v in pairs(origArgs) do
        v = mw.text.trim(v) -- Trim whitespace.
        if k == cfg.demospace or k == cfg.page then
            if v ~= '' then
                args[k] = v
            end
        else
            args[k] = v
        end
    end
    
    return compare()
end

-- Create a wikitable of all possible namespace parameters.
function p.table()
    -- Start the wikitable.
    local ret = '{| class="wikitable"'
        .. '\n|-'
        .. '\n! ' .. cfg.wikitableNamespaceHeader
        .. '\n! ' .. cfg.wikitableAliasesHeader
    
    -- Generate the row for the main namespace.
    ret = ret .. '\n|-'
        .. '\n| ' .. cfg.main
        .. '\n|'
    
    -- Generate the other wikitable rows.
    for nsid, ns in pairs( mw.site.subjectNamespaces ) do
        if nsid ~= 0 then -- Ignore the main namespace, as it is set in cfg.
            local name = '<code>' .. mw.ustring.lower( ns.name ) .. '</code>'
            local aliases = {}
            if ns.canonicalName ~= ns.name then
                table.insert( aliases, '<code>' .. mw.ustring.lower( ns.canonicalName ) .. '</code>' )
            end
            for _, v in ipairs( ns.aliases ) do
                table.insert( aliases, '<code>' .. mw.ustring.lower(v) .. '</code>' )
            end
            ret = ret .. '\n|-'
                .. '\n| ' .. name
                .. '\n| ' .. table.concat( aliases, ', ' )
        end
    end
    
    -- End the wikitable.
    ret = ret .. '\n|-'
        .. '\n|}'
    
    return ret
end

return p