Module:For loop

-- This module implements {{for loop}}.

local getArgs = require('Module:Arguments').getArgs
local yesno = require('Module:Yesno')
local p = {}

function p.main(frame)
 local args = getArgs(frame, {
  trim = false,
  removeBlanks = false
 })
 return p._main(args)
end

function p._main(args)
 local template = args['call'] or 'void'
 local calltemplates = yesno(args.substall or "", true) or not mw.isSubsting()
 local variableParam = args.pv
 variableParam = tonumber(variableParam) or variableParam or 1 -- fix for positional parameters
 local variableValPrefix = args.prefix or ''
 local variableValPostfix = args.postfix or ''
 local sep = args[1] or ''
 local constantArgs = p.getConstants(args)
 local variableVals = p.getVariableVals(args)

 local result = ''
 local addSeparator = false;
 for _, v in ipairs(variableVals) do
  v = mw.text.trim(v)
  if #v > 0 or not yesno(args.skipBlanks) then
   if addSeparator then
    result = result .. sep
   end
   addSeparator = true;
   local targs = constantArgs
   targs[variableParam] = variableValPrefix .. v .. variableValPostfix
   if calltemplates then
    local output = p.callTemplate(template, targs)
    if #mw.text.trim(output) == 0 then
     addSeparator = false
    end
    result = result .. output
   else
    local makeTemplate = require('Module:Template invocation').invocation
    result = result .. makeTemplate(template, targs)
   end
  end
 end
 return result
end

function p.getConstants(args)
 local constantArgNums = p.getArgNums(args, 'pc', 'n')
 local constantArgs = {}
 for _, num in ipairs(constantArgNums) do
  local keyArg = 'pc' .. tostring(num) .. 'n'
  local valArg = 'pc' .. tostring(num) .. 'v'
  local key = args[keyArg]
  key = tonumber(key) or key
  local value = args[valArg]
  constantArgs[key] = value
 end
 return constantArgs
end

function p.getVariableVals(args)
 local variableVals = {}
 if args.start or args.stop or args.by then
  if args[2] then
   error("Both start/stop/by and numbered parameters specified")
  end
  local start = tonumber(args.start or 1)
  local stop = tonumber(args.stop or 1)
  local by = tonumber(args.by or 1)
  for i = start, stop, by do
   variableVals [#variableVals + 1] = i
  end
 else
  for i, v in ipairs(args) do
   if i ~= 1 then
    variableVals[i - 1] = v
   end
  end
 end
 return variableVals
end

function p.getArgNums(args, prefix, suffix)
 -- Returns a table containing the numbers of the arguments that exist
 -- for the specified prefix and suffix.
 local nums = {}
 local pattern = '^' .. prefix .. '([1-9]%d*)' .. suffix .. '$'
 for k, _ in pairs(args) do
  local num = tostring(k):match(pattern)
  if num then
   nums[#nums + 1] = tonumber(num)
  end
 end
 table.sort(nums)
 return nums
end

function p.callTemplate(template, targs)
 return mw.getCurrentFrame():expandTemplate{title = template, args = targs}
end

return p