Add split function to LineSplitter class in dart:convert.

Add split function to LineSplitter class in dart:convert.

The split function returns a lazy iterable of the lines, unlike the convert
function which returns a list.
This makes the function usable on large strings where not all of the lines
are needed.

Closes https://github.com/dart-lang/sdk/issues/23837

R=kevmoo@google.com

Committed: https://github.com/dart-lang/sdk/commit/4ee62465568ecad211b37494b3b9d1fd9661435e

[Lasse Reichstein Nielsen, 2015-07-14 10:07:27]

lrn@google.com changed reviewers:
+ kevmoo@google.com

[Lasse Reichstein Nielsen, 2015-07-14 10:07:28]

The original was far too complex to begin with. I think this is better.

[Lasse Reichstein Nielsen, 2015-07-14 11:30:50]

https://codereview.chromium.org/1240623002/diff/1/sdk/lib/convert/line_splitt...
File sdk/lib/convert/line_splitter.dart (right):

https://codereview.chromium.org/1240623002/diff/1/sdk/lib/convert/line_splitt...
sdk/lib/convert/line_splitter.dart:35: int previousChar = char;
I could add "previousChar = char" to the increment part of the for-loop, but I
think it might break optimizations that depend on an integer increment loop
being simple.

It could be:
  for (int char, previousChar, i = start; i < end; previousChar = char, i++) {
but it's probably not as efficient.

[kevmoo, 2015-07-14 13:35:35]

I"ll take it. :-)

Please update the changelog.

LGTM

[kevmoo, 2015-07-14 13:36:23]

On 2015/07/14 13:35:35, kevmoo wrote:
> I"ll take it. :-)
> 
> Please update the changelog.
> 
> LGTM

also: if you use the CLOSES [link to issue] syntax, github will close the issue
for you

[Lasse Reichstein Nielsen, 2015-07-15 10:26:29]

Committed patchset #2 (id:20001) manually as
4ee62465568ecad211b37494b3b9d1fd9661435e (presubmit successful).

[floitsch, 2015-08-20 13:17:41]

floitsch@google.com changed reviewers:
+ floitsch@google.com

[floitsch, 2015-08-20 13:17:41]

DBC.

https://codereview.chromium.org/1240623002/diff/20001/sdk/lib/convert/line_sp...
File sdk/lib/convert/line_splitter.dart (right):

https://codereview.chromium.org/1240623002/diff/20001/sdk/lib/convert/line_sp...
sdk/lib/convert/line_splitter.dart:30: static Iterable<String> split(String
lines, [int start = 0, int end]) sync* {
Generally we try to keep types in the core libraries, if we have them.
I would prefer returning an Iterable<String> instead of an Iterable<dynamic>.
That said, the complexity must be worth it...

[Lasse Reichstein Nielsen, 2015-08-20 14:00:31]

https://codereview.chromium.org/1240623002/diff/20001/sdk/lib/convert/line_sp...
File sdk/lib/convert/line_splitter.dart (right):

https://codereview.chromium.org/1240623002/diff/20001/sdk/lib/convert/line_sp...
sdk/lib/convert/line_splitter.dart:30: static Iterable<String> split(String
lines, [int start = 0, int end]) sync* {
I'd rather we had added "sync*<int>" like we asked for from the very beginning.