RFR - JDK-8202442 - String::unescape (Code Review)

[Jonathan Gibbons]

If you're making the change, then you might add a test case based on 
Jan's suggestion, testing

     "\u005ct".equals(`\u005ct`.unescape())

-- Jon


On 9/19/18 7:40 AM, Jim Laskey wrote:
> I see and good point.  I think Jon is correct.  If you are using the JLS as the basis of your argument, then you better damn well stick to the JLS.
>
> I’ll make the changes.
>
> Cheers,
>
> — Jim
>
>
>> On Sep 19, 2018, at 11:10 AM, Jan Lahoda <jan.lahoda at oracle.com> wrote:
>>
>> I guess Jon's comment was that (per JLS) the outcome of unicode unescapes can then participate in the escape sequences in String literals. So, this:
>> "\u005ct"
>>
>> is (as far as I know) a single character-literal (a tab), while it seems that
>> `\u005ct`.unescape()
>>
>> is two characters:
>> \t
>>
>> Not sure if that's an intent or not.
>>
>> Jan
>>
>> On 18.9.2018 20:55, Jim Laskey wrote:
>>> The intent, of course, is to offset the raw string literals non-translation of Unicode escapes and escape sequences. That is, have the multi-line cake and eat the escapes too.
>>>
>>> So a developer could have
>>>
>>> 	String s = `
>>>                     \t\tTitle
>>>                     \t\t\tbody
>>> 		   ...
>>>
>>>                     `.align().escape();
>>>
>>> to have tabs inserted in the string.
>>>
>>> "\\" "\u005c\u005c" and `\` all translate to the same string. `\u005c` translates to "\\u005c”. `\u005c`.unescape() thustranslates to be the same as "\\”, "\u005c\u005c" and `\`.
>>>
>>> Cheers,
>>>
>>> — Jim
>>>
>>>
>>>
>>>> On Sep 18, 2018, at 3:33 PM, Jonathan Gibbons <jonathan.gibbons at oracle.com> wrote:
>>>>
>>>> Jim,
>>>>
>>>> In JLS, and hence javac, Unicode escape handling happens early on at a low level, before string escape handling. This means that it is technically possible to write string escape sequences in terms of Unicode escapes.
>>>>
>>>> I'm not suggesting you should do the same here, but you should be aware of the difference, compared to javac behavior.
>>>>
>>>> -- Jon
>>>>
>>>>
>>>> On 9/18/18 10:51 AM, Jim Laskey wrote:
>>>>> Please review the code for String::unescape. Used to translate escape sequences in a string, typically in a raw string literal, into characters represented by those escapes.
>>>>>
>>>>> webrev: http://cr.openjdk.java.net/~jlaskey/8202442/webrev/index.html
>>>>> jbs: https://bugs.openjdk.java.net/browse/JDK-8202442
>>>>> csr: https://bugs.openjdk.java.net/browse/JDK-8202443
>>>>>
>>>>> Cheers,
>>>>>
>>>>> — Jim
>>>>>