Module:LoadData/sandbox

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A more complex version of Module:Data with more options and the ability to select indexes with an inequality operator.

Usage

{{#invoke:LoadData|Module name|index1|2 lteq=index2 limit|...|}}

• Zeroth parameter is the name of the data module to read, without Module:, e.g. Example/data
• Next parameters, for an index N starting at one, are called |N= for the exact index you need, coerced to number if possible, |N lteq= to select the highest numerical index less than or equal to the argument, or |N gteq= for the opposite.
• |template= is a printf-style string to interpolate the resulting value(s) into, e.g. <b>%s</b>.
• |preprocess= is like |template= except that frame:preprocess is run on it; this makes e.g. template transclusions work.
• |if nil= is the string to return if the result is nil. Default is nil, which comes out as the empty string.

The above documentation is transcluded from Module:LoadData/doc. (edit | history)
Editors can experiment in this module's sandbox (edit | diff) and testcases (create) pages.
Add categories to the /doc subpage. Subpages of this module.

local p = {}

-- Finds the next key key <= or >= the given i.
-- operator is ±1
local function findItemRange(data, i, operator)
    local bestIndex = nil
    i = i * operator
    for k, v in pairs(data) do
    	local kop = type(k) == 'number' and k * operator
        if kop and kop <= i and (bestIndex == nil or kop > bestIndex * operator) then
        	bestIndex = k
        end
    end
    if bestIndex then return data[bestIndex] else return nil end
end

local function load(datamodule, frame)
	local args = frame.args
    local data = mw.loadData(datamodule)
    for i = 1, 20 do
        if args[i] then data = data[tonumber(args[i]) or args[i]]
        elseif args[i .. ' lteq'] then
            data = findItemRange(data, tonumber(args[i .. ' lteq']), 1)
        elseif args[i .. ' gteq'] then
            data = findItemRange(data, tonumber(args[i .. ' gteq']), -1)
        else break end
    end
    
    if data == nil then
    	return args['if_nil'] -- not a required argument, OK to return nil here.
    end
    
    if type(data) == 'table' then
    	-- Put the table into another table because the return value of loadData
    	-- is a "fake" table that only has certain metamethods.
    	local realdata = {}
    	for k, v in pairs(data) do
    		realdata[k] = v
    	end
    	data = realdata
    else
    	data = { data }
    end
    
    if args['template'] then
    	return mw.text.unstripNoWiki(args['template']):format(unpack(data))
    elseif args['preprocess'] then
    	return frame:preprocess(mw.text.unstripNoWiki(args['preprocess']):format(unpack(data)))
    else
    	return table.concat(data)
    end
end

return setmetatable({}, {
	__index = function(t, k)
		return function(frame)
			if k:sub(-5) == '.json' then
				return load(mw.text.jsonDecode(mw.title.new(k).getContent()), frame)
			else
			    return load(mw.loadData('Module:' .. k), frame)
			end
	    end
	end
})