index.js 4.2 KB

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  1. var concatMap = require('concat-map');
  2. var balanced = require('balanced-match');
  3. module.exports = expandTop;
  4. var escSlash = '\0SLASH'+Math.random()+'\0';
  5. var escOpen = '\0OPEN'+Math.random()+'\0';
  6. var escClose = '\0CLOSE'+Math.random()+'\0';
  7. var escComma = '\0COMMA'+Math.random()+'\0';
  8. var escPeriod = '\0PERIOD'+Math.random()+'\0';
  9. function numeric(str) {
  10. return parseInt(str, 10) == str
  11. ? parseInt(str, 10)
  12. : str.charCodeAt(0);
  13. }
  14. function escapeBraces(str) {
  15. return str.split('\\\\').join(escSlash)
  16. .split('\\{').join(escOpen)
  17. .split('\\}').join(escClose)
  18. .split('\\,').join(escComma)
  19. .split('\\.').join(escPeriod);
  20. }
  21. function unescapeBraces(str) {
  22. return str.split(escSlash).join('\\')
  23. .split(escOpen).join('{')
  24. .split(escClose).join('}')
  25. .split(escComma).join(',')
  26. .split(escPeriod).join('.');
  27. }
  28. // Basically just str.split(","), but handling cases
  29. // where we have nested braced sections, which should be
  30. // treated as individual members, like {a,{b,c},d}
  31. function parseCommaParts(str) {
  32. if (!str)
  33. return [''];
  34. var parts = [];
  35. var m = balanced('{', '}', str);
  36. if (!m)
  37. return str.split(',');
  38. var pre = m.pre;
  39. var body = m.body;
  40. var post = m.post;
  41. var p = pre.split(',');
  42. p[p.length-1] += '{' + body + '}';
  43. var postParts = parseCommaParts(post);
  44. if (post.length) {
  45. p[p.length-1] += postParts.shift();
  46. p.push.apply(p, postParts);
  47. }
  48. parts.push.apply(parts, p);
  49. return parts;
  50. }
  51. function expandTop(str) {
  52. if (!str)
  53. return [];
  54. return expand(escapeBraces(str), true).map(unescapeBraces);
  55. }
  56. function identity(e) {
  57. return e;
  58. }
  59. function embrace(str) {
  60. return '{' + str + '}';
  61. }
  62. function isPadded(el) {
  63. return /^-?0\d/.test(el);
  64. }
  65. function lte(i, y) {
  66. return i <= y;
  67. }
  68. function gte(i, y) {
  69. return i >= y;
  70. }
  71. function expand(str, isTop) {
  72. var expansions = [];
  73. var m = balanced('{', '}', str);
  74. if (!m || /\$$/.test(m.pre)) return [str];
  75. var isNumericSequence = /^-?\d+\.\.-?\d+(?:\.\.-?\d+)?$/.test(m.body);
  76. var isAlphaSequence = /^[a-zA-Z]\.\.[a-zA-Z](?:\.\.-?\d+)?$/.test(m.body);
  77. var isSequence = isNumericSequence || isAlphaSequence;
  78. var isOptions = /^(.*,)+(.+)?$/.test(m.body);
  79. if (!isSequence && !isOptions) {
  80. // {a},b}
  81. if (m.post.match(/,.*}/)) {
  82. str = m.pre + '{' + m.body + escClose + m.post;
  83. return expand(str);
  84. }
  85. return [str];
  86. }
  87. var n;
  88. if (isSequence) {
  89. n = m.body.split(/\.\./);
  90. } else {
  91. n = parseCommaParts(m.body);
  92. if (n.length === 1) {
  93. // x{{a,b}}y ==> x{a}y x{b}y
  94. n = expand(n[0], false).map(embrace);
  95. if (n.length === 1) {
  96. var post = m.post.length
  97. ? expand(m.post, false)
  98. : [''];
  99. return post.map(function(p) {
  100. return m.pre + n[0] + p;
  101. });
  102. }
  103. }
  104. }
  105. // at this point, n is the parts, and we know it's not a comma set
  106. // with a single entry.
  107. // no need to expand pre, since it is guaranteed to be free of brace-sets
  108. var pre = m.pre;
  109. var post = m.post.length
  110. ? expand(m.post, false)
  111. : [''];
  112. var N;
  113. if (isSequence) {
  114. var x = numeric(n[0]);
  115. var y = numeric(n[1]);
  116. var width = Math.max(n[0].length, n[1].length)
  117. var incr = n.length == 3
  118. ? Math.abs(numeric(n[2]))
  119. : 1;
  120. var test = lte;
  121. var reverse = y < x;
  122. if (reverse) {
  123. incr *= -1;
  124. test = gte;
  125. }
  126. var pad = n.some(isPadded);
  127. N = [];
  128. for (var i = x; test(i, y); i += incr) {
  129. var c;
  130. if (isAlphaSequence) {
  131. c = String.fromCharCode(i);
  132. if (c === '\\')
  133. c = '';
  134. } else {
  135. c = String(i);
  136. if (pad) {
  137. var need = width - c.length;
  138. if (need > 0) {
  139. var z = new Array(need + 1).join('0');
  140. if (i < 0)
  141. c = '-' + z + c.slice(1);
  142. else
  143. c = z + c;
  144. }
  145. }
  146. }
  147. N.push(c);
  148. }
  149. } else {
  150. N = concatMap(n, function(el) { return expand(el, false) });
  151. }
  152. for (var j = 0; j < N.length; j++) {
  153. for (var k = 0; k < post.length; k++) {
  154. var expansion = pre + N[j] + post[k];
  155. if (!isTop || isSequence || expansion)
  156. expansions.push(expansion);
  157. }
  158. }
  159. return expansions;
  160. }