Module:Format ISBN
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Documentation for this module may be created at Module:Format ISBN/doc
require ('strict'); local data = mw.loadData ('Module:Format ISBN/data'); -- fetch separator positioning data local hyphen_pos_t = data.hyphen_pos_t; -- the hyphen positioning data k/v table local index_t = data.index_t; -- an index sequence into the hyphen positioning data table; used by binary_search() local idx_count = data.count; -- from count = #index_t; in ~/data; used by binary_search() --[[--------------------------< B I N A R Y _ S E A R C H >---------------------------------------------------- do a binary search for the hyphen positioning data for <target_isbn> in <hyphen_pos_t> using its index sequence <index_t>. accepts one input <target_isbn> (a string) which it converts to a number returns index into <hyphen_pos_t> as a number when proper formatting is found; nil else ]] local function binary_search (target_isbn) target_isbn = tonumber (target_isbn); -- convert to number because index_t[x] values are numbers if (index_t[1] >= target_isbn) or (index_t[idx_count] < target_isbn) then -- invalid; out of range; 9780000000000 to whatever the last value is return; -- TODO: return something meaningful? end local idx_bot = 1; -- initialize to index 1 (first element in <index_t>) local idx_top = idx_count; -- initialize to index of last element in <index_t> while idx_bot ~= idx_top do local idx_mid = math.ceil ((idx_bot + idx_top) / 2); -- get the mid-point in the index sequence if index_t[idx_mid] >= target_isbn then -- when mid-point index value is greater than or equal to the target isbn if index_t[idx_mid-1] < target_isbn then -- and when the preceding <index_t> value is less than the target isbn return index_t[idx_mid]; -- we found the correct mapping for <target> isbn; return index into <hyphen_pos_t> end idx_top = idx_mid - 1; -- adjust <idx_top> else idx_bot = idx_mid; -- adjust <idx_bot> end end mw.logObject ('didn\'t find formatting for isbn: ' .. target_isbn); -- just in case for the nonce end --[[--------------------------< C O N V E R T _ T O _ I S B N 1 0 >-------------------------------------------- convert 13-digit isbn to 10-digit isbn; removes 978 GS1 prefix and recalculates the check digit takes a single input; the 13-digit isbn as a string without separators assumes that the GS1 prefix is 978; there is no mapping between isbn10 and 979-prefixed isbn13. calling functions are required to ensure that <isbn13> is a properly formed string of 13 digits (no separators) that begins with 978. ]] local function convert_to_isbn10 (isbn13) local isbn9 = isbn13:sub (4, 12); -- get the 9 digits of <isbn13> that follow the '978' GS1 prefix (drop the check digit) local check = 0; -- initialize the check digit calculation local i = 1; -- index for j=10, 2, -1 do -- <j> is weighting for each of the 9 digits; counting down, left to right check = check + tonumber (isbn9:sub (i, i)) * j; -- accumulate the sum the weighted-digit-products i = i + 1; -- bump the index end check = check % 11; -- remainder of the weighted-digit-products divided by 11 if 0 == check then return isbn9 .. '0'; -- special case else check = 11 - check; -- calculate the check digit return isbn9 .. ((10 == check) and 'X' or check); -- when <check> is ten, use 'X'; <check> else end end --[[--------------------------< C O N V E R T _ T O _ I S B N 1 3 >-------------------------------------------- convert 10-digit isbn to 13-digit isbn; adds 978 GS1 prefix and recalculates the check digit takes a single input; the 10-digit isbn as a string (no separators) ]] local function convert_to_isbn13 (isbn10) local isbn12 = '978'.. isbn10:sub(1, 9); -- concatenate '978' with first 9 digits of <isbn10> (drop the check digit) local check = 0; -- initialize the check digit calculation for i=1, 12 do -- for the first 12 digits ('978' and 9 others) check = check + tonumber (isbn12:sub (i, i)) * (3 - (i % 2) * 2); -- accumulate checksum end return isbn12 .. ((10 - (check % 10)) %10); -- extract check digit from checksum; append and done end --[[--------------------------< _ F O R M A T _ I S B N >------------------------------------------------------ Module entry point when require()'d into another module takes five inputs: <isbn_str> – isbn as a string <show_err_msg>: boolean: when true, shows error message returned from check_isbn(); no message else <separator>: boolean: when true, use space character as separator; hyphen else <template_name>: supplied by the template for use in error messaging <output_format>: a value of 10 or 13 dictates the format of the output; other values ignored returns formatted sbn, isbn10, or isbn13 (whichever was the input or per |out=) on success; initial <isbn_str> else ]] local function _format_isbn (isbn_str, show_err_msg, separator, output_format, template_name) if (not isbn_str) or ('' == isbn_str) then return ''; -- empty or nil input? empty output end local isbn_str_raw = isbn_str; -- this will be the return value if unable to format isbn_str = isbn_str:gsub ('[^%dX]', ''); -- strip all formatting (spaces and hyphens) from the isbn/sbn local flags = {}; -- a convenient place for flag stuff if '13' == output_format then -- set a flag for output format; ignored when <isbn_str> is an sbn flags.out13 = true; elseif '10' == output_format then flags.out10 = true; end if 9 == #isbn_str then -- looks like an sbn? isbn_str = '0' .. isbn_str; -- convert to isbn10 flags.sbn = true; -- set a flag end local err_msg = require ("Module:Check isxn").check_isbn ({args={isbn_str, template_name=template_name}}); -- does <isbn_str> 'look' like a valid isbn? does not check ranging if '' ~= err_msg then -- when there is an error message if show_err_msg then -- and we are showing error messages return isbn_str_raw, err_msg; -- return our input and the message else return isbn_str_raw; -- not showing error messages; return our input without the message end end if 13 == #isbn_str and flags.out10 then -- if isbn13 but we want an isbn10 output flags.isbn10_check_digit = (convert_to_isbn10 (isbn_str)):sub (-1); -- calculate and extract the isbn10 check digit for later end if 10 == #isbn_str then -- if isbn10 or sbn flags.isbn10_check_digit = isbn_str:sub (-1); -- extract the check digit for later isbn_str = convert_to_isbn13 (isbn_str); -- convert isbn10 to isbn13 for formatting end local index = binary_search (isbn_str); -- look for the formatting that applies to <isbn_str> if index then -- if found local format_t = hyphen_pos_t[index]; -- get the formatting sequence local result_t = {isbn_str:sub (1, 3)}; -- init <result_t> with prefix; the GS1 prefix element ('978' or '979') local digit_ptr = 4; -- initialize to point at registration group element for _, n in ipairs (format_t) do -- loop through the formatting sequence to build a sequence of isbn13 elements table.insert (result_t, isbn_str:sub (digit_ptr, digit_ptr+n-1)); -- add the digits from <isbn_str>[<digit_ptr>] to <isbn_str>[<digit_ptr+n-1>] to <result_t> sequence digit_ptr = digit_ptr + n; -- advance the digit pointer end table.insert (result_t, isbn_str:sub (13)); -- and add the check digit element to <result_t> isbn_str = table.concat (result_t, separator and ' ' or '-'); -- assemble formatted <isbn_str> with space or hyphen (default) separators if flags.isbn10_check_digit then -- if we saved the check digit from an sbn or isbn10 if flags.sbn then -- when input is an sbn isbn_str = isbn_str:gsub ('^978%-0%-', ''):gsub ('%d$', flags.isbn10_check_digit); -- remove GS1 prefix element and registration group element; restore check digit else -- when input is an isbn10 if not flags.out13 then isbn_str = isbn_str:gsub ('^978%-', ''):gsub ('%d$', flags.isbn10_check_digit); -- remove GS1 prefix element; restore check digit end end end return isbn_str; -- return formatted <isbn_str> end return isbn_str_raw; -- should never actually be reached; but, if we do, return original input string end --[[--------------------------< F O R M A T _ P L A I N >------------------------------------------------------ plain text output: no linking to Special:BookSources no error message output – on error, return input; for use in cs1|2 template |isbn= params, no point in causing confusion due to multiple error messages |separator=space – render formatted ISBN with spaces instead of hyphens |out= – takes either of 10 or 13 to specify the output format if different from the default {{#invoke:format isbn|format_plain}} ]] local function format_plain (frame) local args_t = require ('Module:Arguments').getArgs (frame); -- get template and invoke parameters local isbn_str = args_t[1]; local separator = 'space' == args_t.separator; -- boolean: when true use space separator; hyphen else local output_format = args_t.out; -- 10 or 13 to convert input format to the other for output return _format_isbn (isbn_str, nil, separator, output_format); -- no error messaging end --[[--------------------------< F O R M A T _ L I N K >-------------------------------------------------------- linked text output: links to Special:BookSources |suppress-errors=yes – suppress error messages |separator=space – render formatted ISBN with spaces instead of hyphens |out= – takes either of 10 or 13 to specify the output format if different from the default {{#invoke:format isbn|format_linked|template=Format ISBN link}} ]] local function format_linked (frame) local args_t = require ('Module:Arguments').getArgs (frame); -- get template and invoke parameters local isbn_str = args_t[1]; local show_err_msg = 'yes' ~= args_t['suppress-errors']; -- always show errors unless |suppress-errors=yes local separator = 'space' == args_t.separator; -- boolean: when true use space separator; hyphen else local output_format = args_t.out; -- 10 or 13 to convert input format to the other for output local formatted_isbn_str, err_msg = _format_isbn (isbn_str, show_err_msg, separator, output_format, args_t.template_name); -- show error messages unless suppressed if err_msg then return formatted_isbn_str .. ' ' .. err_msg; -- return unformatted, unlinked isbn and error message else return '[[Special:BookSources/' ..isbn_str .. '|' .. formatted_isbn_str ..']]'; -- return formatted and linked isbn end end --[[--------------------------< E X P O R T S >---------------------------------------------------------------- ]] return { format_plain = format_plain, -- template entry points format_linked = format_linked, _format_isbn = _format_isbn, -- entry point when this module require()'d into another module }