Module:Chessboard mxn/Sandbox explained

local p =

function chessboard(args, size, rows, cols, rev, trans, lightdark, altprefix, letters, numbers, header, footer, align, clear) function colchar(col) return (col <= 26) and ("abcdefghijklmnopqrstuvwxyz"):sub(col, col) or ("abcdefghijklmnopqrstuvwxyz"):sub(math.floor((col-1)/26), math.floor((col-1)/26)) .. ("abcdefghijklmnopqrstuvwxyz"):sub(col-math.floor((col-1)/26)*26, col-math.floor((col-1)/26)*26) end function image_square(pc, row, col, size, t, flip, altprefix) local colornames = local piecenames = local symnames = local color = mw.ustring.gsub(pc, '^.*(%w)(%w).*$', '%2') or local piece = mw.ustring.gsub(pc, '^.*(%w)(%w).*$', '%1') or local alt = altprefix .. colchar(col) .. row .. ' ' if (colornames[color] and piecenames[piece]) then alt = alt .. colornames[color] .. ' ' .. piecenames[piece] else alt = alt .. (symnames[piece .. color] or piece .. ' ' .. color) end local ld = t and 't' or ((((row + col + flip) % 2)

0) and 'd' or 'l') return string.format('', piece, color, ld, size, size, alt, alt) end

function letters_row(rev, num_lt, num_rt, cols) local res = '' .. (num_lt and '' or ) .. '' for k = 1, cols do res = res .. colchar(rev and (cols - k + 1) or k) .. '' end res = res .. '' .. (num_lt and '' or ) .. '' return res end local letters_tp = letters:match('both') or letters:match('top') local letters_bt = letters:match('both') or letters:match('bottom') local numbers_lt = numbers:match('both') or numbers:match('left') local numbers_rt = numbers:match('both') or numbers:match('right') local width = cols * size + 2 local flip = lightdark and 1 or 0 if (numbers_lt) then width = width + 18 end if (numbers_rt) then width = width + 18 end

local b = local caption =

if (letters_tp) then b = b .. letters_row(rev, numbers_lt, numbers_rt, cols) .. '\n' end for trow = 1,rows do local row = rev and trow or (rows - trow + 1) b = b .. '' if (numbers_lt) then b = b .. '' .. row .. '' end for tcol = 1,cols do local col = rev and (cols - tcol + 1) or tcol local idx = cols*(rows - row) + col + 2 if (args[idx]

nil) then args[idx] = ' ' end local img = image_square(args[idx]:match('%w%w') or , row, col, size, trans, flip, altprefix) local bg = (((trow + tcol + flip) % 2)

0) and '#ffce9e' or '#d18b47' b = b .. '' .. img .. '' end if (numbers_rt) then b = b .. '' .. row .. '' end b = b .. '' end if (letters_bt) then b = b .. letters_row(rev, numbers_lt, numbers_rt, cols) .. '\n' end

if footer:match('^%s*$') then else caption = '

' .. footer .. '

\n' end b = '

'

if noframe then return b else return '

' .. '

' .. header .. '

' .. '\n

\n' .. b .. '\n' .. caption .. '

' end end

function convertFenToArgs(fen) -- converts FEN notation to an array of positions, offset by 2 local res = -- Loop over rows, which are delimited by / for srow in string.gmatch("/" .. fen, "/%w+") do srow = srow:gsub("/","") -- clean up row -- Loop over all letters and numbers in the row -- Since Lua regexes do not have the | operator, we have -- to spell things out local index = 1 local piece = "" -- Piece can also be empty squares local place = 0 local pstart = 0 local pend = 0 local length = srow:len while index <= length do -- Look for a number. Can have multiple digits pstart, pend = srow:find("%d+", index) if pstart

index then piece = srow:sub(pstart, pend) index = pend + 1 for k=1,tonumber(piece) do table.insert(res,' ') end else -- If number not found, look for a letter (piece on board) pstart = srow:find("%a",index) if pstart

index then piece = srow:sub(pstart, pstart) index = pstart + 1 -- l: White (light); d: Black (dark) local color = piece:match('%u') and 'l' or 'd' piece = piece:lower table.insert(res, piece .. color) else index = length + 1 -- Break loop end end end end return resend

function p.board(frame) local args = frame.args local pargs = frame:getParent.args local size = (args.size or pargs.size) or '26' local reverse = (args.reverse or pargs.reverse or ):lower

"true" local trans = (args.transparent or pargs.transparent or ):lower

"true" local lightdark = (args.lightdark or pargs.lightdark or ):lower

"swap" local altprefix = args.altprefix or pargs.altprefix or local rows = args.rows or pargs.rows or 8 local cols = args.cols or pargs.cols or 8 local letters = (args.letters or pargs.letters or 'both'):lower local numbers = (args.numbers or pargs.numbers or 'both'):lower local header = mw.ustring.gsub(args[2] or pargs[2] or , '^%s*(.-)%s*$', '%1') local footer = args[3 + rows*cols] or pargs[3 + rows*cols] or local align = (args[1] or pargs[1] or 'tright'):lower local clear = (args.clear or pargs.clear) or (align:match('tright') and 'right' or 'none') local noframe = (args.noframe or pargs.noframe or ):lower

"true" local fen = args.fen or pargs.fen

size = mw.ustring.match(size, '[%d]+') or '26' -- remove px from size if (fen) then align = (args.align or pargs.align or 'tright'):lower clear = (args.clear or pargs.clear) or (align:match('tright') and 'right' or 'none') header = args.header or pargs.header or footer = args.footer or pargs.footer or return chessboard(convertFenToArgs(fen), size, rows, cols, reverse, trans, lightdark, altprefix, letters, numbers, header, footer, align, clear, noframe) end if args[3] then return chessboard(args, size, rows, cols, reverse, trans, lightdark, altprefix, letters, numbers, header, footer, align, clear, noframe) else return chessboard(pargs, size, rows, cols, reverse, trans, lightdark, altprefix, letters, numbers, header, footer, align, clear, noframe) end end

return p