Module:TableTools

    From FOSSBotsWiki

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

    --[[
    ------------------------------------------------------------------------------------
    --                               TableTools                                       --
    --                                                                                --
    -- This module includes a number of functions for dealing with Lua tables.        --
    -- It is a meta-module, meant to be called from other Lua modules, and should     --
    -- not be called directly from #invoke.                                           --
    ------------------------------------------------------------------------------------
    --]]
    
    local libraryUtil = require('libraryUtil')
    
    local p = {}
    
    -- Define often-used variables and functions.
    local floor = math.floor
    local infinity = math.huge
    local checkType = libraryUtil.checkType
    local checkTypeMulti = libraryUtil.checkTypeMulti
    
    --[[
    ------------------------------------------------------------------------------------
    -- isPositiveInteger
    --
    -- This function returns true if the given value is a positive integer, and false
    -- if not. Although it doesn't operate on tables, it is included here as it is
    -- useful for determining whether a given table key is in the array part or the
    -- hash part of a table.
    ------------------------------------------------------------------------------------
    --]]
    function p.isPositiveInteger(v)
    	return type(v) == 'number' and v >= 1 and floor(v) == v and v < infinity
    end
    
    --[[
    ------------------------------------------------------------------------------------
    -- isNan
    --
    -- This function returns true if the given number is a NaN value, and false
    -- if not. Although it doesn't operate on tables, it is included here as it is
    -- useful for determining whether a value can be a valid table key. Lua will
    -- generate an error if a NaN is used as a table key.
    ------------------------------------------------------------------------------------
    --]]
    function p.isNan(v)
    	return type(v) == 'number' and tostring(v) == '-nan'
    end
    
    --[[
    ------------------------------------------------------------------------------------
    -- shallowClone
    --
    -- This returns a clone of a table. The value returned is a new table, but all
    -- subtables and functions are shared. Metamethods are respected, but the returned
    -- table will have no metatable of its own.
    ------------------------------------------------------------------------------------
    --]]
    function p.shallowClone(t)
    	local ret = {}
    	for k, v in pairs(t) do
    		ret[k] = v
    	end
    	return ret
    end
    
    --[[
    ------------------------------------------------------------------------------------
    -- removeDuplicates
    --
    -- This removes duplicate values from an array. Non-positive-integer keys are
    -- ignored. The earliest value is kept, and all subsequent duplicate values are
    -- removed, but otherwise the array order is unchanged.
    ------------------------------------------------------------------------------------
    --]]
    function p.removeDuplicates(t)
    	checkType('removeDuplicates', 1, t, 'table')
    	local isNan = p.isNan
    	local ret, exists = {}, {}
    	for i, v in ipairs(t) do
    		if isNan(v) then
    			-- NaNs can't be table keys, and they are also unique, so we don't need to check existence.
    			ret[#ret + 1] = v
    		else
    			if not exists[v] then
    				ret[#ret + 1] = v
    				exists[v] = true
    			end
    		end	
    	end
    	return ret
    end			
    
    --[[
    ------------------------------------------------------------------------------------
    -- numKeys
    --
    -- This takes a table and returns an array containing the numbers of any numerical
    -- keys that have non-nil values, sorted in numerical order.
    ------------------------------------------------------------------------------------
    --]]
    function p.numKeys(t)
    	checkType('numKeys', 1, t, 'table')
    	local isPositiveInteger = p.isPositiveInteger
    	local nums = {}
    	for k, v in pairs(t) do
    		if isPositiveInteger(k) then
    			nums[#nums + 1] = k
    		end
    	end
    	table.sort(nums)
    	return nums
    end
    
    --[[
    ------------------------------------------------------------------------------------
    -- affixNums
    --
    -- This takes a table and returns an array containing the numbers of keys with the
    -- specified prefix and suffix. For example, for the table
    -- {a1 = 'foo', a3 = 'bar', a6 = 'baz'} and the prefix "a", affixNums will
    -- return {1, 3, 6}.
    ------------------------------------------------------------------------------------
    --]]
    function p.affixNums(t, prefix, suffix)
    	checkType('affixNums', 1, t, 'table')
    	checkType('affixNums', 2, prefix, 'string', true)
    	checkType('affixNums', 3, suffix, 'string', true)
    
    	local function cleanPattern(s)
    		-- Cleans a pattern so that the magic characters ()%.[]*+-?^$ are interpreted literally.
    		return s:gsub('([%(%)%%%.%[%]%*%+%-%?%^%$])', '%%%1')
    	end
    
    	prefix = prefix or ''
    	suffix = suffix or ''
    	prefix = cleanPattern(prefix)
    	suffix = cleanPattern(suffix)
    	local pattern = '^' .. prefix .. '([1-9]%d*)' .. suffix .. '$'
    
    	local nums = {}
    	for k, v in pairs(t) do
    		if type(k) == 'string' then			
    			local num = mw.ustring.match(k, pattern)
    			if num then
    				nums[#nums + 1] = tonumber(num)
    			end
    		end
    	end
    	table.sort(nums)
    	return nums
    end
    
    --[[
    ------------------------------------------------------------------------------------
    -- numData
    --
    -- Given a table with keys like ("foo1", "bar1", "foo2", "baz2"), returns a table
    -- of subtables in the format 
    -- { [1] = {foo = 'text', bar = 'text'}, [2] = {foo = 'text', baz = 'text'} }
    -- Keys that don't end with an integer are stored in a subtable named "other".
    -- The compress option compresses the table so that it can be iterated over with
    -- ipairs.
    ------------------------------------------------------------------------------------
    --]]
    function p.numData(t, compress)
    	checkType('numData', 1, t, 'table')
    	checkType('numData', 2, compress, 'boolean', true)
    	local ret = {}
    	for k, v in pairs(t) do
    		local prefix, num = mw.ustring.match(tostring(k), '^([^0-9]*)([1-9][0-9]*)$')
    		if num then
    			num = tonumber(num)
    			local subtable = ret[num] or {}
    			if prefix == '' then
    				-- Positional parameters match the blank string; put them at the start of the subtable instead.
    				prefix = 1
    			end
    			subtable[prefix] = v
    			ret[num] = subtable
    		else
    			local subtable = ret.other or {}
    			subtable[k] = v
    			ret.other = subtable
    		end
    	end
    	if compress then
    		local other = ret.other
    		ret = p.compressSparseArray(ret)
    		ret.other = other
    	end
    	return ret
    end
    
    --[[
    ------------------------------------------------------------------------------------
    -- compressSparseArray
    --
    -- This takes an array with one or more nil values, and removes the nil values
    -- while preserving the order, so that the array can be safely traversed with
    -- ipairs.
    ------------------------------------------------------------------------------------
    --]]
    function p.compressSparseArray(t)
    	checkType('compressSparseArray', 1, t, 'table')
    	local ret = {}
    	local nums = p.numKeys(t)
    	for _, num in ipairs(nums) do
    		ret[#ret + 1] = t[num]
    	end
    	return ret
    end
    
    --[[
    ------------------------------------------------------------------------------------
    -- sparseIpairs
    --
    -- This is an iterator for sparse arrays. It can be used like ipairs, but can
    -- handle nil values.
    ------------------------------------------------------------------------------------
    --]]
    function p.sparseIpairs(t)
    	checkType('sparseIpairs', 1, t, 'table')
    	local nums = p.numKeys(t)
    	local i = 0
    	local lim = #nums
    	return function ()
    		i = i + 1
    		if i <= lim then
    			local key = nums[i]
    			return key, t[key]
    		else
    			return nil, nil
    		end
    	end
    end
    
    --[[
    ------------------------------------------------------------------------------------
    -- size
    --
    -- This returns the size of a key/value pair table. It will also work on arrays,
    -- but for arrays it is more efficient to use the # operator.
    ------------------------------------------------------------------------------------
    --]]
    
    function p.size(t)
    	checkType('size', 1, t, 'table')
    	local i = 0
    	for k in pairs(t) do
    		i = i + 1
    	end
    	return i
    end
    
    
    local function defaultKeySort(item1, item2)
    	-- "number" < "string", so numbers will be sorted before strings.
    	local type1, type2 = type(item1), type(item2)
    	if type1 ~= type2 then
    		return type1 < type2
    	else -- This will fail with table, boolean, function.
    		return item1 < item2
    	end
    end
    
    --[[
    	Returns a list of the keys in a table, sorted using either a default
    	comparison function or a custom keySort function.
    ]]
    function p.keysToList(t, keySort, checked)
    	if not checked then
    		checkType('keysToList', 1, t, 'table')
    		checkTypeMulti('keysToList', 2, keySort, { 'function', 'boolean', 'nil' })
    	end
    	
    	local list = {}
    	local index = 1
    	for key, value in pairs(t) do
    		list[index] = key
    		index = index + 1
    	end
    	
    	if keySort ~= false then
    		keySort = type(keySort) == 'function' and keySort or defaultKeySort
    		
    		table.sort(list, keySort)
    	end
    	
    	return list
    end
    
    --[[
    	Iterates through a table, with the keys sorted using the keysToList function.
    	If there are only numerical keys, sparseIpairs is probably more efficient.
    ]]
    function p.sortedPairs(t, keySort)
    	checkType('sortedPairs', 1, t, 'table')
    	checkType('sortedPairs', 2, keySort, 'function', true)
    	
    	local list = p.keysToList(t, keySort, true)
    	
    	local i = 0
    	return function()
    		i = i + 1
    		local key = list[i]
    		if key ~= nil then
    			return key, t[key]
    		else
    			return nil, nil
    		end
    	end
    end
    
    --[[
    	Returns true if all keys in the table are consecutive integers starting at 1.
    --]]
    function p.isArray(t)
    	checkType("isArray", 1, t, "table")
    	
    	local i = 0
    	for k, v in pairs(t) do
    		i = i + 1
    		if t[i] == nil then
    			return false
    		end
    	end
    	return true
    end
    
    -- { "a", "b", "c" } -> { a = 1, b = 2, c = 3 }
    function p.invert(array)
    	checkType("invert", 1, array, "table")
    	
    	local map = {}
    	for i, v in ipairs(array) do
    		map[v] = i
    	end
    	
    	return map
    end
    
    --[[
    	{ "a", "b", "c" } -> { ["a"] = true, ["b"] = true, ["c"] = true }
    --]]
    function p.listToSet(t)
    	checkType("listToSet", 1, t, "table")
    	
    	local set = {}
    	for _, item in ipairs(t) do
    		set[item] = true
    	end
    	
    	return set
    end
    
    --[[
    	Recursive deep copy function.
    	Preserves identities of subtables.
    	
    ]]
    local function _deepCopy(orig, includeMetatable, already_seen)
    	-- Stores copies of tables indexed by the original table.
    	already_seen = already_seen or {}
    	
    	local copy = already_seen[orig]
    	if copy ~= nil then
    		return copy
    	end
    	
    	if type(orig) == 'table' then
    		copy = {}
    		for orig_key, orig_value in pairs(orig) do
    			copy[deepcopy(orig_key, includeMetatable, already_seen)] = deepcopy(orig_value, includeMetatable, already_seen)
    		end
    		already_seen[orig] = copy
    		
    		if includeMetatable then
    			local mt = getmetatable(orig)
    			if mt ~= nil then
    				local mt_copy = deepcopy(mt, includeMetatable, already_seen)
    				setmetatable(copy, mt_copy)
    				already_seen[mt] = mt_copy
    			end
    		end
    	else -- number, string, boolean, etc
    		copy = orig
    	end
    	return copy
    end
    
    function p.deepCopy(orig, noMetatable, already_seen)
    	checkType("deepCopy", 3, already_seen, "table", true)
    	
    	return _deepCopy(orig, not noMetatable, already_seen)
    end
    
    --[[
    	Concatenates all values in the table that are indexed by a number, in order.
    	sparseConcat{ a, nil, c, d }  =>  "acd"
    	sparseConcat{ nil, b, c, d }  =>  "bcd"
    ]]
    function p.sparseConcat(t, sep, i, j)
    	local list = {}
    	
    	local list_i = 0
    	for _, v in p.sparseIpairs(t) do
    		list_i = list_i + 1
    		list[list_i] = v
    	end
    	
    	return table.concat(list, sep, i, j)
    end
    
    --[[
    -- Finds the length of an array, or of a quasi-array with keys such
    -- as "data1", "data2", etc., using an exponential search algorithm. 
    -- It is similar to the operator #, but may return
    -- a different value when there are gaps in the array portion of the table.
    -- Intended to be used on data loaded with mw.loadData. For other tables, use #.
    -- Note: #frame.args in frame object always be set to 0, regardless of 
    -- the number of unnamed template parameters, so use this function for
    -- frame.args.
    --]]
    
    function p.length(t, prefix)
    	-- requiring module inline so that [[Module:Exponential search]]
    	-- which is only needed by this one function
    	-- doesn't get millions of transclusions
    	local expSearch = require("Module:Exponential search")
    	checkType('length', 1, t, 'table')
    	checkType('length', 2, prefix, 'string', true)
    	return expSearch(function(i)
    		local key
    		if prefix then
    			key = prefix .. tostring(i)
    		else
    			key = i
    		end
    		return t[key] ~= nil
    	end) or 0
    end
    function p.inArray(arr, valueToFind)
    	checkType("inArray", 1, arr, "table")
    	
    	-- if valueToFind is nil, error?
    	
    	for _, v in ipairs(arr) do
    		if v == valueToFind then
    			return true
    		end
    	end
    	
    	return false
    end
    
    return p