# 模組:Gapnum

```local p = {}

local getArgs

function p.main(frame)
if not getArgs then
getArgs = require('Module:Arguments').getArgs
end

local args = getArgs(frame, {wrappers = 'Template:Gapnum'})
local n = args[1]

if not n then
error('需要参数1')
elseif not tonumber(n) and not tonumber(n, 36) then -- Validates any number with base ≤ 36
error('无法将"' .. args[1] .. '"转换为数字')
end

local gap = args.gap
local precision = tonumber(args.prec)

return p.gaps(n,{gap=gap,prec=precision})
end

-- Not named p._main so that it has a better function name when required by Module:Val
function p.gaps(n,tbl)
local nstr = tostring(n)
if not tbl then
tbl = {}
end
local gap = tbl.gap or '.25em'

local int_part, frac_part = p.groups(n,tbl.prec)

local ret = mw.html.create('span')
:css('white-space','nowrap')
-- No gap necessary on first group
:wikitext(table.remove(int_part,1))

-- Build int part
for _, v in ipairs(int_part) do
ret:tag('span')
:css('margin-left',gap)
:wikitext(v)
end

if frac_part then
-- The first group after the decimal shouldn't have a gap
ret:wikitext('.' .. table.remove(frac_part,1))
-- Build frac part
for _, v in ipairs(frac_part) do
ret:tag('span')
:css('margin-left',gap)
:wikitext(v)
end
end

return ret
end

-- Creates tables where each element is a different group of the number
function p.groups(num,precision)
local nstr = tostring(num)
if not precision then
precision = -1
end

local decimalloc = nstr:find('.', 1, true)
local int_part, frac_part
if decimalloc == nil then
int_part = nstr
else
int_part = nstr:sub(1, decimalloc-1)
frac_part = nstr:sub(decimalloc + 1)
end
-- only define ret_i as an empty table, let ret_d stay nil
local ret_i,ret_d = {}
-- Loop to handle most of the groupings; from right to left, so that if a group has less than 3 members, it will be the first group
while int_part:len() > 3 do
-- Insert in first spot, since we're moving backwards
table.insert(ret_i,1,int_part:sub(-3))
int_part = int_part:sub(1,-4)
end
-- handle any left over numbers
if int_part:len() > 0 then
table.insert(ret_i,1,int_part)
end

if precision ~= 0 and frac_part then
ret_d = {}
if precision == -1 then
precision = frac_part:len()
end
-- Reduce the length of the string if required precision is less than actual precision
-- OR
-- Increase it (by adding 0s) if the required precision is more than actual
local offset = precision - frac_part:len()
if offset < 0 then
frac_part = frac_part:sub(1,precision)
elseif offset > 0 then
frac_part = frac_part .. string.rep('0', offset)
end

-- Allow groups of 3 or 2 (3 first)
for v in string.gmatch(frac_part,'%d%d%d?') do
table.insert(ret_d,v)
end
-- Preference for groups of 4 instead of groups of 1 at the end
if #frac_part % 3 == 1 then
if frac_part:len() == 1 then
ret_d = {frac_part}
else
local last_g = ret_d[#ret_d] or ''
last_g = last_g..frac_part:sub(-1)
ret_d[#ret_d] = last_g
end
end
end

return ret_i,ret_d
end

return p
```