Raw String Literal Library Support

[Xueming Shen]

On 3/13/18, 5:12 PM, Jonathan Bluett-Duncan wrote:
> Paul,
>
> AFAICT, one sort of behaviour which String.split() allows which
> Pattern.splitAsStream() and the proposed String.splits() don't is allowing
> a negative limit, e.g. String.split(string, -1).
>
> Over at http://errorprone.info/bugpattern/StringSplitter, they argue that a
> limit of -1 has less surprising behaviour than the default of 0, because
> e.g. "".split(":") produces [] (empty array), whereas ":".split(":")
> produces [""] (array with an empty string), which IMO is not consistent.
>
> This compares with ":".split(":", -1) and "".split(":", -1) which produce
> ["", ""] (array with two empty strings, each representing ends of `:`) and
> [] (empty array) respectively - more consistent IMO.
>
> Should String.splits(`\n|\r\n?`) follow the behaviour of String.split(...,
> 0) or String.split(..., -1)?  I'd personally argue for the latter.

While these look really confusing, but ":".split(":", n) and 
"".split(":", n) are really two
different scenario. One is for a matched delimiter and the other is a 
split with no
matched delimiter, in which the spec specifies clearly that it returns 
the original string,
in this case the empty string "". Arguably these two don't have to be 
"consistent".

Personally I think the returned list/array from string.split(regex, -1) 
might be kinda of
"surprising" for end user, in which it has a "trailing" empty string, as 
it appears to be
useless in most use scenario and you probably have to do some special 
deal with it.

-Sherman



>
> Cheers,
> Jonathan
>
> On 13 March 2018 at 23:22, Paul Sandoz<paul.sandoz at oracle.com>  wrote:
>
>>
>>> On Mar 13, 2018, at 3:49 PM, John Rose<john.r.rose at oracle.com>  wrote:
>>>
>>> On Mar 13, 2018, at 6:47 AM, Jim Laskey<james.laskey at oracle.com>  wrote:
>>>> …
>>>> A. Line support.
>>>>
>>>> public Stream<String>  lines()
>>>>
>>> Suggest factoring this as:
>>>
>>> public Stream<String>  splits(String regex) { }
>> +1
>>
>> This is a natural companion to the existing array returning method (as it
>> was the case on Pattern when we added splitAsStream), where one can use a
>> limit() operation to achieve the same effect as the limit parameter on the
>> array returning method.
>>
>>
>>> public Stream<String>  lines() { return splits(`\n|\r\n?`); }
>>>
>> See also Files/BufferedReader.lines. (Without going into details
>> Files.lines has some interesting optimizations.)
>>
>> Paul.