In Harmony we should be able to make this even more beautiful using iterators
[1]:
If we add:
String.prototype.[iterator] = function() {
var s = this;
return {
index: 0,
next: function() {
if (this.index >= s.length) {
throw StopIteration;
}
let cp = s.codePointAt(index);
index += cp > 0xFFFF ? 2 : 1;
return cp;
}
}
}
clients can write:
for (codePoint of str) {
// do something with codePoint
}
Norbert
[1] http://wiki.ecmascript.org/doku.php?id=harmony:iterators
On Mar 16, 2012, at 17:04 , Jonas Höglund wrote:
> On Sat, 17 Mar 2012 00:23:25 +0100, Mark Davis ☕ <[email protected]>
> wrote:
>
>> Whew, a lot of work, Norbert. Looks quite good. My one question is whether
>> it is worth having a mechanism for iteration.
>>
>> OLD CODE
>> for (int i = 0; i < s.length(); ++) {
>> var x = s.charAt(i);
>> // do something with x
>> }
>>
>> Using your mechanism, one would write:
>>
>> NEW CODE
>> for (int i = 0; i < s.length(); ++) {
>> var x = s.codePointAt(i);
>> // do something with x
>> if (x > 0xFFFF) {
>> ++i;
>> }
>> }
>>
>> In Java, for example, I *really* wish you could write:
>>
>> DESIRED
>>
>> for (int codepoint : s) {
>> // do something with x
>> }
>>
>> However, maybe this kind of iteration is rare enough in ES that it suffices
>> to document the pattern under NEW CODE.
>>
>
> That's the beauty of ECMAScript; it's extensible. :-)
>
> String.prototype.forEachCodePoint = function(fun) {
> for (var i=0; i<s.length; i++) {
> var x = s.codePointAt(i)
> fun(x, s)
> if (x > 0xFFFF) { ++i }
> }
> }
>
> "hello".forEachCodepoint(function(x) {
> // do something with x
> })
>
>> Thanks for all your work!
>>
>>
>>> proposal for upgrading ECMAScript to a Unicode version released in this
>> century
>>
>> This was amusing; could have said "this millennium" ;-)
>> ------------------------------
>> Mark <https://plus.google.com/114199149796022210033>
>> *
>> *
>> *— Il meglio è l’inimico del bene —*
>> **
>>
>
> Jonas
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