Difference between revisions of "Module:TableTools"

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-- This module includes a number of functions that can be useful when dealing with Lua tables.
+
--[[
 +
------------------------------------------------------------------------------------
 +
--                              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 = {}
 
local p = {}
Line 6: Line 16:
 
local floor = math.floor
 
local floor = math.floor
 
local infinity = math.huge
 
local infinity = math.huge
 +
local checkType = libraryUtil.checkType
  
 
--[[
 
--[[
-----------------------------------------------------------------------------------
+
------------------------------------------------------------------------------------
-- Helper functions
+
-- 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)
 +
if type(v) == 'number' and v >= 1 and floor(v) == v and v < infinity then
 +
return true
 +
else
 +
return false
 +
end
 +
end
  
local function isPositiveInteger(num)
+
--[[
-- Returns true if the given number is a positive integer, and false if not.
+
------------------------------------------------------------------------------------
if type(num) == 'number' and num >= 1 and floor(num) == num and num < infinity then
+
-- 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)
 +
if type(v) == 'number' and tostring(v) == '-nan' then
 
return true
 
return true
 
else
 
else
Line 23: Line 55:
  
 
--[[
 
--[[
-----------------------------------------------------------------------------------
+
------------------------------------------------------------------------------------
-- compressSparseArray
+
-- 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 an array with one or more nil values, and removes the nil values
+
-- This takes a table and returns an array containing the numbers of any numerical
-- while preserving the order, so that the array can be safely traversed with
+
-- keys that have non-nil values, sorted in numerical order.
-- ipairs.
+
------------------------------------------------------------------------------------
-----------------------------------------------------------------------------------
 
 
--]]
 
--]]
function p.compressSparseArray(t)
+
function p.numKeys(t)
local nums, ret = {}, {}
+
checkType('numKeys', 1, t, 'table')
 +
local isPositiveInteger = p.isPositiveInteger
 +
local nums = {}
 
for k, v in pairs(t) do
 
for k, v in pairs(t) do
 
if isPositiveInteger(k) then
 
if isPositiveInteger(k) then
Line 39: Line 116:
 
end
 
end
 
table.sort(nums)
 
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.
 +
s = s:gsub('([%(%)%%%.%[%]%*%+%-%?%^%$])', '%%%1')
 +
return s
 +
end
 +
 +
prefix = prefix or ''
 +
suffix = suffix or ''
 +
prefix = cleanPattern(prefix)
 +
suffix = cleanPattern(suffix)
 +
local pattern = '^' .. prefix .. '([1-9]%d*)' .. suffix .. '$'
 +
 +
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
 
for _, num in ipairs(nums) do
 
ret[#ret + 1] = t[num]
 
ret[#ret + 1] = t[num]
 
end
 
end
 
return ret
 
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
 
end
  
 
return p
 
return p

Latest revision as of 14:04, 9 February 2015

--[[


-- 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

--[[


-- 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) if type(v) == 'number' and v >= 1 and floor(v) == v and v < infinity then return true else return false end 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) if type(v) == 'number' and tostring(v) == '-nan' then return true else return false end 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. s = s:gsub('([%(%)%%%.%[%]%*%+%-%?%^%$])', '%%%1') return s 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

return p