Module:Namespace detect

Documentation for this module may be created at Module:Namespace detect/doc

--[[
--------------------------------------------------------------------------------
--                                                                            --
--                            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. The     --
-- module can also use the corresponding subject namespace value if it is     --
-- used on a talk page. Parameter names can be configured for different wikis --
-- by altering the values in the "cfg" table in                               --
-- Module:Namespace detect/config.                                            --
--                                                                            --
--------------------------------------------------------------------------------
--]]

local data = mw.loadData('Module:Namespace detect/data')
local argKeys = data.argKeys
local cfg = data.cfg
local mappings = data.mappings

local yesno = require('Module:Yesno')
local mArguments -- Lazily initialise Module:Arguments
local mTableTools -- Lazily initilalise Module:TableTools
local ustringLower = mw.ustring.lower

local p = {}

local function fetchValue(t1, t2)
    -- Fetches a value from the table t1 for the first key in array t2 where
    -- a non-nil value of t1 exists.
    for i, key in ipairs(t2) do
        local value = t1[key]
        if value ~= nil then
            return value
        end
    end
    return nil
end

local function equalsArrayValue(t, value)
    -- Returns true if value equals a value in the array t. Otherwise
    -- returns false.
    for i, arrayValue in ipairs(t) do
        if value == arrayValue then
            return true
        end
    end
    return false
end

function p.getPageObject(page)
    -- Get the page object, passing the function through pcall in case of
    -- errors, e.g. being over the expensive function count limit.
    if page then
        local success, pageObject = pcall(mw.title.new, page)
        if success then
            return pageObject
        else
            return nil
        end
    else
        return mw.title.getCurrentTitle()
    end
end

-- Provided for backward compatibility with other modules
function p.getParamMappings()
    return mappings
end

local function getNamespace(args)
    -- This function gets the namespace name from the page object.
    local page = fetchValue(args, argKeys.demopage)
    if page == '' then
        page = nil
    end
    local demospace = fetchValue(args, argKeys.demospace)
    if demospace == '' then
        demospace = nil
    end
    local subjectns = fetchValue(args, argKeys.subjectns)
    local ret
    if demospace then
        -- Handle "demospace = main" properly.
        if equalsArrayValue(argKeys.main, ustringLower(demospace)) then
            ret = mw.site.namespaces[0].name
        else
            ret = demospace
        end
    else
        local pageObject = p.getPageObject(page)
        if pageObject then
            if pageObject.isTalkPage then
                -- Get the subject namespace if the option is set,
                -- otherwise use "talk".
                if yesno(subjectns) then
                    ret = mw.site.namespaces[pageObject.namespace].subject.name
                else
                    ret = 'talk'
                end
            else
                ret = pageObject.nsText
            end
        else
            return nil -- return nil if the page object doesn't exist.
        end
    end
    ret = ret:gsub('_', ' ')
    return ustringLower(ret)
end

function p._main(args)
    -- Check the parameters stored in the mappings table for any matches.
    local namespace = getNamespace(args) or 'other' -- "other" avoids nil table keys
    local params = mappings[namespace] or {}
    local ret = fetchValue(args, params)
    --[[
    -- If there were no matches, 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 ret == nil then
        ret = fetchValue(args, argKeys.other)
    end
    return ret
end

function p.main(frame)
    mArguments = require('Module:Arguments')
    local args = mArguments.getArgs(frame, {removeBlanks = false})
    local ret = p._main(args)
    return ret or ''
end

function p.table(frame)
    --[[
    -- Create a wikitable of all subject namespace parameters, for
    -- documentation purposes. The talk parameter is optional, in case it
    -- needs to be excluded in the documentation.
    --]]
    
    -- Load modules and initialise variables.
    mTableTools = require('Module:TableTools')
    local namespaces = mw.site.namespaces
    local cfg = data.cfg
    local useTalk = type(frame) == 'table'
        and type(frame.args) == 'table'
        and yesno(frame.args.talk) -- Whether to use the talk parameter.
    
    -- Get the header names.
    local function checkValue(value, default)
        if type(value) == 'string' then
            return value
        else
            return default
        end
    end
    local nsHeader = checkValue(cfg.wikitableNamespaceHeader, 'Namespace')
    local aliasesHeader = checkValue(cfg.wikitableAliasesHeader, 'Aliases')

    -- Put the namespaces in order.
    local mappingsOrdered = {}
    for nsname, params in pairs(mappings) do
        if useTalk or nsname ~= 'talk' then
            local nsid = namespaces[nsname].id
            -- Add 1, as the array must start with 1; nsid 0 would be lost otherwise.
            nsid = nsid + 1
            mappingsOrdered[nsid] = params
        end
    end
    mappingsOrdered = mTableTools.compressSparseArray(mappingsOrdered)

    -- Build the table.
    local ret = '{| class="wikitable"'
        .. '\n|-'
        .. '\n! ' .. nsHeader
        .. '\n! ' .. aliasesHeader
    for i, params in ipairs(mappingsOrdered) do
        for j, param in ipairs(params) do
            if j == 1 then
                ret = ret .. '\n|-'
                    .. '\n| <code>' .. param .. '</code>'
                    .. '\n| '
            elseif j == 2 then
                ret = ret .. '<code>' .. param .. '</code>'
            else
                ret = ret .. ', <code>' .. param .. '</code>'
            end
        end
    end
    ret = ret .. '\n|-'
        .. '\n|}'
    return ret
end

return p