1 // sprintf() for JavaScript 0.7-beta1
2 // http://www.diveintojavascript.com/projects/javascript-sprintf
4 // Copyright (c) Alexandru Marasteanu <alexaholic [at) gmail (dot] com>
5 // All rights reserved.
6 var strRepeat = require('./helper/strRepeat');
7 var toString = Object.prototype.toString;
8 var sprintf = (function() {
9 function get_type(variable) {
10 return toString.call(variable).slice(8, -1).toLowerCase();
13 var str_repeat = strRepeat;
15 var str_format = function() {
16 if (!str_format.cache.hasOwnProperty(arguments[0])) {
17 str_format.cache[arguments[0]] = str_format.parse(arguments[0]);
19 return str_format.format.call(null, str_format.cache[arguments[0]], arguments);
22 str_format.format = function(parse_tree, argv) {
23 var cursor = 1, tree_length = parse_tree.length, node_type = '', arg, output = [], i, k, match, pad, pad_character, pad_length;
24 for (i = 0; i < tree_length; i++) {
25 node_type = get_type(parse_tree[i]);
26 if (node_type === 'string') {
27 output.push(parse_tree[i]);
29 else if (node_type === 'array') {
30 match = parse_tree[i]; // convenience purposes only
31 if (match[2]) { // keyword argument
33 for (k = 0; k < match[2].length; k++) {
34 if (!arg.hasOwnProperty(match[2][k])) {
35 throw new Error(sprintf('[_.sprintf] property "%s" does not exist', match[2][k]));
37 arg = arg[match[2][k]];
39 } else if (match[1]) { // positional argument (explicit)
42 else { // positional argument (implicit)
46 if (/[^s]/.test(match[8]) && (get_type(arg) != 'number')) {
47 throw new Error(sprintf('[_.sprintf] expecting number but found %s', get_type(arg)));
50 case 'b': arg = arg.toString(2); break;
51 case 'c': arg = String.fromCharCode(arg); break;
52 case 'd': arg = parseInt(arg, 10); break;
53 case 'e': arg = match[7] ? arg.toExponential(match[7]) : arg.toExponential(); break;
54 case 'f': arg = match[7] ? parseFloat(arg).toFixed(match[7]) : parseFloat(arg); break;
55 case 'o': arg = arg.toString(8); break;
56 case 's': arg = ((arg = String(arg)) && match[7] ? arg.substring(0, match[7]) : arg); break;
57 case 'u': arg = Math.abs(arg); break;
58 case 'x': arg = arg.toString(16); break;
59 case 'X': arg = arg.toString(16).toUpperCase(); break;
61 arg = (/[def]/.test(match[8]) && match[3] && arg >= 0 ? '+'+ arg : arg);
62 pad_character = match[4] ? match[4] == '0' ? '0' : match[4].charAt(1) : ' ';
63 pad_length = match[6] - String(arg).length;
64 pad = match[6] ? str_repeat(pad_character, pad_length) : '';
65 output.push(match[5] ? arg + pad : pad + arg);
68 return output.join('');
71 str_format.cache = {};
73 str_format.parse = function(fmt) {
74 var _fmt = fmt, match = [], parse_tree = [], arg_names = 0;
76 if ((match = /^[^\x25]+/.exec(_fmt)) !== null) {
77 parse_tree.push(match[0]);
79 else if ((match = /^\x25{2}/.exec(_fmt)) !== null) {
82 else if ((match = /^\x25(?:([1-9]\d*)\$|\(([^\)]+)\))?(\+)?(0|'[^$])?(-)?(\d+)?(?:\.(\d+))?([b-fosuxX])/.exec(_fmt)) !== null) {
85 var field_list = [], replacement_field = match[2], field_match = [];
86 if ((field_match = /^([a-z_][a-z_\d]*)/i.exec(replacement_field)) !== null) {
87 field_list.push(field_match[1]);
88 while ((replacement_field = replacement_field.substring(field_match[0].length)) !== '') {
89 if ((field_match = /^\.([a-z_][a-z_\d]*)/i.exec(replacement_field)) !== null) {
90 field_list.push(field_match[1]);
92 else if ((field_match = /^\[(\d+)\]/.exec(replacement_field)) !== null) {
93 field_list.push(field_match[1]);
96 throw new Error('[_.sprintf] huh?');
101 throw new Error('[_.sprintf] huh?');
103 match[2] = field_list;
108 if (arg_names === 3) {
109 throw new Error('[_.sprintf] mixing positional and named placeholders is not (yet) supported');
111 parse_tree.push(match);
114 throw new Error('[_.sprintf] huh?');
116 _fmt = _fmt.substring(match[0].length);
124 module.exports = sprintf;