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192 lines
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JavaScript

var concatMap = require('concat-map');
var balanced = require('balanced-match');
module.exports = expandTop;
var escSlash = '\0SLASH'+Math.random()+'\0';
var escOpen = '\0OPEN'+Math.random()+'\0';
var escClose = '\0CLOSE'+Math.random()+'\0';
var escComma = '\0COMMA'+Math.random()+'\0';
var escPeriod = '\0PERIOD'+Math.random()+'\0';
function numeric(str) {
return parseInt(str, 10) == str
? parseInt(str, 10)
: str.charCodeAt(0);
}
function escapeBraces(str) {
return str.split('\\\\').join(escSlash)
.split('\\{').join(escOpen)
.split('\\}').join(escClose)
.split('\\,').join(escComma)
.split('\\.').join(escPeriod);
}
function unescapeBraces(str) {
return str.split(escSlash).join('\\')
.split(escOpen).join('{')
.split(escClose).join('}')
.split(escComma).join(',')
.split(escPeriod).join('.');
}
// Basically just str.split(","), but handling cases
// where we have nested braced sections, which should be
// treated as individual members, like {a,{b,c},d}
function parseCommaParts(str) {
if (!str)
return [''];
var parts = [];
var m = balanced('{', '}', str);
if (!m)
return str.split(',');
var pre = m.pre;
var body = m.body;
var post = m.post;
var p = pre.split(',');
p[p.length-1] += '{' + body + '}';
var postParts = parseCommaParts(post);
if (post.length) {
p[p.length-1] += postParts.shift();
p.push.apply(p, postParts);
}
parts.push.apply(parts, p);
return parts;
}
function expandTop(str) {
if (!str)
return [];
return expand(escapeBraces(str), true).map(unescapeBraces);
}
function identity(e) {
return e;
}
function embrace(str) {
return '{' + str + '}';
}
function isPadded(el) {
return /^-?0\d/.test(el);
}
function lte(i, y) {
return i <= y;
}
function gte(i, y) {
return i >= y;
}
function expand(str, isTop) {
var expansions = [];
var m = balanced('{', '}', str);
if (!m || /\$$/.test(m.pre)) return [str];
var isNumericSequence = /^-?\d+\.\.-?\d+(?:\.\.-?\d+)?$/.test(m.body);
var isAlphaSequence = /^[a-zA-Z]\.\.[a-zA-Z](?:\.\.-?\d+)?$/.test(m.body);
var isSequence = isNumericSequence || isAlphaSequence;
var isOptions = /^(.*,)+(.+)?$/.test(m.body);
if (!isSequence && !isOptions) {
// {a},b}
if (m.post.match(/,.*\}/)) {
str = m.pre + '{' + m.body + escClose + m.post;
return expand(str);
}
return [str];
}
var n;
if (isSequence) {
n = m.body.split(/\.\./);
} else {
n = parseCommaParts(m.body);
if (n.length === 1) {
// x{{a,b}}y ==> x{a}y x{b}y
n = expand(n[0], false).map(embrace);
if (n.length === 1) {
var post = m.post.length
? expand(m.post, false)
: [''];
return post.map(function(p) {
return m.pre + n[0] + p;
});
}
}
}
// at this point, n is the parts, and we know it's not a comma set
// with a single entry.
// no need to expand pre, since it is guaranteed to be free of brace-sets
var pre = m.pre;
var post = m.post.length
? expand(m.post, false)
: [''];
var N;
if (isSequence) {
var x = numeric(n[0]);
var y = numeric(n[1]);
var width = Math.max(n[0].length, n[1].length)
var incr = n.length == 3
? Math.abs(numeric(n[2]))
: 1;
var test = lte;
var reverse = y < x;
if (reverse) {
incr *= -1;
test = gte;
}
var pad = n.some(isPadded);
N = [];
for (var i = x; test(i, y); i += incr) {
var c;
if (isAlphaSequence) {
c = String.fromCharCode(i);
if (c === '\\')
c = '';
} else {
c = String(i);
if (pad) {
var need = width - c.length;
if (need > 0) {
var z = new Array(need + 1).join('0');
if (i < 0)
c = '-' + z + c.slice(1);
else
c = z + c;
}
}
}
N.push(c);
}
} else {
N = concatMap(n, function(el) { return expand(el, false) });
}
for (var j = 0; j < N.length; j++) {
for (var k = 0; k < post.length; k++) {
var expansion = pre + N[j] + post[k];
if (!isTop || isSequence || expansion)
expansions.push(expansion);
}
}
return expansions;
}