Module:File link

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

-- This module provides a library for formatting file wikilinks.

local yesno = require('Module:Yesno')
local checkType = require('libraryUtil').checkType

local p = {}

function p._main(args)
  checkType('_main', 1, args, 'table')

  -- This is basically libraryUtil.checkTypeForNamedArg, but we are rolling our
  -- own function to get the right error level.
  local function checkArg(key, val, level)
    if type(val) ~= 'string' then
      error(string.format(
        "type error in '%s' parameter of '_main' (expected string, got %s)",
        key, type(val)
      ), level)
    end
  end

  local ret = {}

  -- Adds a positional parameter to the buffer.
  local function addPositional(key)
    local val = args[key]
    if not val then
      return nil
    end
    checkArg(key, val, 4)
    ret[#ret + 1] = val
  end

  -- Adds a named parameter to the buffer. We assume that the parameter name
  -- is the same as the argument key.
  local function addNamed(key)
    local val = args[key]
    if not val then
      return nil
    end
    checkArg(key, val, 4)
    ret[#ret + 1] = key .. '=' .. val
  end

  -- Filename
  checkArg('file', args.file, 3)
  ret[#ret + 1] = 'File:' .. args.file

  -- Format
  if args.format then
    checkArg('format', args.format)
    if args.formatfile then
      checkArg('formatfile', args.formatfile)
      ret[#ret + 1] = args.format .. '=' .. args.formatfile
    else
      ret[#ret + 1] = args.format
    end
  end

  -- Border
  if yesno(args.border) then
    ret[#ret + 1] = 'border'
  end

  addPositional('location')
  addPositional('alignment')
  addPositional('size')
  addNamed('upright')
  addNamed('link')
  addNamed('alt')
  addNamed('page')
  addNamed('class')
  addNamed('lang')
  addNamed('start')
  addNamed('end')
  addNamed('thumbtime')
  addPositional('caption')

  return string.format('[[%s]]', table.concat(ret, '|'))
end

function p.main(frame)
  local origArgs = require('Module:Arguments').getArgs(frame, {
    wrappers = 'Template:File link'
  })
  if not origArgs.file then
    error("'file' parameter missing from [[Template:File link]]", 0)
  end

  -- Copy the arguments that were passed to a new table to avoid looking up
  -- every possible parameter in the frame object.
  local args = {}
  for k, v in pairs(origArgs) do
    -- Make _BLANK a special argument to add a blank parameter. For use in
    -- conditional templates etc. it is useful for blank arguments to be
    -- ignored, but we still need a way to specify them so that we can do
    -- things like [[File:Example.png|link=]].
    if v == '_BLANK' then
      v = ''
    end
    args[k] = v
  end
  return p._main(args)
end

return p