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Groups > comp.lang.java.programmer > #20334

Re: Unicode escapes and String literals?

Newsgroups comp.lang.java.programmer
Date 2012-12-14 15:16 -0800
References <kad3d6$eoo$1@dont-email.me> <kad4io$see$1@news2.informatik.uni-stuttgart.de> <kad7rb$btq$1@dont-email.me> <8d054b85-a6ed-4bab-a8a9-81e967a84fda@googlegroups.com> <0camc85sbkqmmgic2r05toov7p65c0hoi1@4ax.com>
Message-ID <7db64abf-3fdd-412b-8af6-11b6e0a7231c@googlegroups.com> (permalink)
Subject Re: Unicode escapes and String literals?
From Lew <lewbloch@gmail.com>

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rossum wrote:
> Lew wrote:
>>>>>  if you create a String with \u0066\u0065\u0064 in it
>>
>>Exactly how?
> 
> StringBuilder sb = new StringBuilder(18);
>   sb.append('\\');
>   sb.append("u0066");
>   sb.append('\\');
>   sb.append("u0065");
>   sb.append('\\');
>   sb.append("u0064");
>         
>   String ss = sb.toString();
>   System.out.println(ss);
> 
> Produces: \u0066\u0065\u0064
> 
> Which still leaves the question why?

This has been explained to death upthread already.

Those are not Unicode escapes, that's why.

You have created the String literal that comprises backslashes, the letter "u" and 
various digits. That happens at runtime.

There is no way for the pre-compiler to see those and convert them.

That code sequence is exactly equivalent to this one:

  StringBuilder sb = new StringBuilder(\u0031\u0038); 
  sb.append('\u005c\u005c\u0027)\u003b 
  sb.append("\u0075\u0030\u0030\u0036\u0036"); 
  sb.append('\u005c\u005c\u0027)\u003b 
  sb.append("u006\u0035\u0022); 
  sb.append('\u005c\u005c\u0027)\u003b 
  sb.append(\u0022\u00750064"); 

Unicode escape sequence processing is a pre-compiler operation, not a compiler 
operation and not a run-time operation. 

To do what you want you have to parse the string and convert it yourself.

-- 
Lew

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Thread

Unicode escapes and String literals? Knute Johnson <nospam@knutejohnson.com> - 2012-12-13 09:31 -0800
  Re: Unicode escapes and String literals? Thomas Richter <thor@math.tu-berlin.de> - 2012-12-13 18:51 +0100
    Re: Unicode escapes and String literals? Knute Johnson <nospam@knutejohnson.com> - 2012-12-13 10:47 -0800
      Re: Unicode escapes and String literals? Lew <lewbloch@gmail.com> - 2012-12-13 11:41 -0800
        Re: Unicode escapes and String literals? rossum <rossum48@coldmail.com> - 2012-12-14 13:32 +0000
          Re: Unicode escapes and String literals? Lew <lewbloch@gmail.com> - 2012-12-14 15:16 -0800
      Re: Unicode escapes and String literals? markspace <-@.> - 2012-12-13 12:58 -0800
        Re: Unicode escapes and String literals? David Lamb <dalamb@cs.queensu.ca> - 2012-12-13 16:21 -0500
          Re: Unicode escapes and String literals? markspace <-@.> - 2012-12-13 14:00 -0800
            Re: Unicode escapes and String literals? David Lamb <dalamb@cs.queensu.ca> - 2012-12-13 17:17 -0500
            Re: Unicode escapes and String literals? David Lamb <dalamb@cs.queensu.ca> - 2012-12-13 17:19 -0500
            Re: Unicode escapes and String literals? Lew <lewbloch@gmail.com> - 2012-12-13 17:11 -0800
          Re: Unicode escapes and String literals? Arne Vajhøj <arne@vajhoej.dk> - 2012-12-13 19:38 -0500
  Re: Unicode escapes and String literals? Daniel Pitts <newsgroup.nospam@virtualinfinity.net> - 2012-12-13 11:46 -0800
    Re: Unicode escapes and String literals? Daniel Pitts <newsgroup.nospam@virtualinfinity.net> - 2012-12-13 11:49 -0800
    Re: Unicode escapes and String literals? Knute Johnson <nospam@knutejohnson.com> - 2012-12-13 14:55 -0800
      Re: Unicode escapes and String literals? markspace <-@.> - 2012-12-13 15:32 -0800
  Re: Unicode escapes and String literals? Arne Vajhøj <arne@vajhoej.dk> - 2012-12-13 18:09 -0500
    Re: Unicode escapes and String literals? Daniel Pitts <newsgroup.nospam@virtualinfinity.net> - 2012-12-13 15:52 -0800
      Re: Unicode escapes and String literals? Arne Vajhøj <arne@vajhoej.dk> - 2012-12-13 19:40 -0500
    Re: Unicode escapes and String literals? Knute Johnson <nospam@knutejohnson.com> - 2012-12-13 16:11 -0800
      Re: Unicode escapes and String literals? Arne Vajhøj <arne@vajhoej.dk> - 2012-12-13 19:43 -0500
        Re: Unicode escapes and String literals? Knute Johnson <nospam@knutejohnson.com> - 2012-12-13 17:08 -0800
  Re: Unicode escapes and String literals? Roedy Green <see_website@mindprod.com.invalid> - 2012-12-14 02:28 -0800
    Re: Unicode escapes and String literals? Arne Vajhøj <arne@vajhoej.dk> - 2012-12-14 21:05 -0500
  Re: Unicode escapes and String literals? Roedy Green <see_website@mindprod.com.invalid> - 2012-12-17 02:42 -0800

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