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Groups > comp.lang.java.programmer > #39450

Re: Character.isIdentifierIgnorable

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On 4/25/20 1:01 PM, Arne Vajhøj wrote:
> On 4/25/2020 12:57 PM, Arne Vajhøj wrote:
>> On 4/24/2020 11:36 PM, Jeff Higgins wrote:
>>> On 4/24/20 10:24 PM, Arne Vajhøj wrote:
>>>> On 4/24/2020 8:37 PM, Jeff Higgins wrote:
>>>>> On 4/24/20 8:29 PM, Arne Vajhøj wrote:
>>>>>> I think we are in the far out corners of the language.
>>>>>>
>>>>> Well, yeah, but still.
>>>>> And still leaves me questioning motivation for ignorable chars.
>>>>
>>>> We would need to find someone working at SUN back in the mid 90's
>>>> to know.
>>>>
>>>> If I were to guess then somebody got the "smart" idea that
>>>> the language should not distinguish between names where
>>>> the difference could not be seen when type'd/cat'ed and
>>>> then someone else later added the \uXXXX feature.
>>>>
>>> Maybe not that far back.
>>>
>>> from JLS-3.8 for JavaSE 9
>>> Two identifiers are the same only if they are identical, that is, 
>>> have the same
>>> Unicode character for each letter or digit. Identifiers that have the 
>>> same external
>>> appearance may yet be different.
>>>
>>> from JLS-3.8 for JavaSE 10
>>> Two identifiers are the same only if, after ignoring characters that are
>>> ignorable, the identifiers have the same Unicode character for each 
>>> letter
>>> or digit. An ignorable character is a character for which the method
>>> Character.isIdentifierIgnorable(int) returns true. Identifiers that 
>>> have the
>>> same external appearance may yet be different.
>>
>> But Java 8 javac did ignore them??
> 
> So does Java 7 javac.
> 
> Java 6 javac gives me an error when trying to create the class file,
> which likely means that it is not ignoring these characters.
> 
Thanks. I don't have earlier than 8 easily available.
Was wondering.

I was wondering when Character,isIdentifierIgnorable(int codepoint)
became available. The earliest javadoc that i can find is 5 and is
available there. A Sun press release from 1997 features
"Global language support based on Unicode 2.0 standards" so maybe
available from then?

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Thread

Character.isIdentifierIgnorable Jeff Higgins <invalid@invalid.org> - 2020-04-24 18:46 -0400
  Re: Character.isIdentifierIgnorable Arne Vajhøj <arne@vajhoej.dk> - 2020-04-24 18:54 -0400
    Re: Character.isIdentifierIgnorable Martin Gregorie <martin@mydomain.invalid> - 2020-04-24 23:07 +0000
    Re: Character.isIdentifierIgnorable Jeff Higgins <invalid@invalid.org> - 2020-04-24 20:12 -0400
      Re: Character.isIdentifierIgnorable Arne Vajhøj <arne@vajhoej.dk> - 2020-04-24 20:29 -0400
        Re: Character.isIdentifierIgnorable Jeff Higgins <invalid@invalid.org> - 2020-04-24 20:37 -0400
          Re: Character.isIdentifierIgnorable Arne Vajhøj <arne@vajhoej.dk> - 2020-04-24 22:24 -0400
            Re: Character.isIdentifierIgnorable Jeff Higgins <invalid@invalid.org> - 2020-04-24 23:36 -0400
              Re: Character.isIdentifierIgnorable Arne Vajhøj <arne@vajhoej.dk> - 2020-04-25 12:57 -0400
                Re: Character.isIdentifierIgnorable Arne Vajhøj <arne@vajhoej.dk> - 2020-04-25 13:01 -0400
                Re: Character.isIdentifierIgnorable Jeff Higgins <invalid@invalid.org> - 2020-04-25 13:39 -0400
                Re: Character.isIdentifierIgnorable Arne Vajhøj <arne@vajhoej.dk> - 2020-04-25 13:51 -0400
                Re: Character.isIdentifierIgnorable Jeff Higgins <invalid@invalid.org> - 2020-04-25 14:36 -0400
            Re: Character.isIdentifierIgnorable Jeff Higgins <invalid@invalid.org> - 2020-04-24 23:41 -0400
    Re: Character.isIdentifierIgnorable Jeff Higgins <invalid@invalid.org> - 2020-04-24 20:25 -0400
      Re: Character.isIdentifierIgnorable Arne Vajhøj <arne@vajhoej.dk> - 2020-04-24 20:32 -0400
        Re: Character.isIdentifierIgnorable Jeff Higgins <invalid@invalid.org> - 2020-04-24 20:42 -0400
          Re: Character.isIdentifierIgnorable Jeff Higgins <invalid@invalid.org> - 2020-04-25 09:53 -0400
            Re: Character.isIdentifierIgnorable Arne Vajhøj <arne@vajhoej.dk> - 2020-04-25 12:55 -0400
              Re: Character.isIdentifierIgnorable Jeff Higgins <invalid@invalid.org> - 2020-04-25 13:43 -0400

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