Could we add \a as an escape sequence for bell?

[David Alayachew]

Woah, thanks.

So, in your second example, it's literally complaining because, as far as
the Java compiler is concerned, I typed in a literal new line in between
the single quotes, right? Like this?

System.out.println('
');

Correct?

Very important context, ty vm.

So, \7 is fine because that actually is an escape sequence. Much like \n
and friends.

But \uXXXX gets turned into the literal bytes, which means that something
like a new line gets treated as if I literally pressed the new line button
on my keyboard, which means that it's treated not as a new line character
in my string, but as a new line character in my source file itself lol.

Ty vm.


On Mon, Oct 27, 2025, 9:44 AM Pavel Rappo <pavel.rappo at gmail.com> wrote:

> Correcting a typo*:
>
>     jshell> System.out.println('\u000A')
>     |  Error:
>     |  illegal line end in character literal
>     |  System.out.println('\u000A')
>     |
>
>
> On Mon, Oct 27, 2025 at 1:32 PM Pavel Rappo <pavel.rappo at gmail.com> wrote:
> >
> > A word of caution. While in this use case the difference is probably
> > non-essential, Unicode escapes (e.g. \u0007) are __not__ a kind of
> > escape sequences (e.g. \7). The former are translated into raw bytes
> > __before__ the compiler goes any further. The latter are recognised by
> > the compiler only in context of character literals, strings, or text
> > blocks.
> >
> > To illustrate the difference, let's consider "line feed" (0xA):
> >
> >     jshell> System.out.println('\n')
> >
> >
> >
> >     jshell> System.out.println('\000A')
> >     |  Error:
> >     |  unclosed character literal
> >     |  System.out.println('\000A')
> >     |                     ^
> >
> > While the former is recognised within the context of a character
> > literal, the latter just breaks the source code in a similar way as if
> > the source code had the actual line feed in it.
> >
> > Unicode escapes allow you to simply input a Unicode character "by
> > reference". This is convenient in some cases, such as when your
> > environment cannot output these characters conveniently or display
> > them properly.
> >
> > -Pavel
> >
> > On Mon, Oct 27, 2025 at 12:56 PM David Alayachew
> > <davidalayachew at gmail.com> wrote:
> > >
> > > Ah, I misread the JLS Language Grammar!
> > >
> > > I was aware of \u0007, but not \7. I see now that that works. Then
> nevermind, that meets my needs just fine. No need for my suggestion.
> > >
> > > The 4 digit unicode is fine, a good escape hatch, but also easy to
> forget, since my brain interprets all 4 digits as significant. And char
> bell = 7; is also unideal. But a 1 digit escape works perfectly for me.
> Would have preferred \a, but \7 is more explicit and easier to look up.
> > >
> > > Ty vm!
> > >
> > > On Mon, Oct 27, 2025, 6:15 AM Andrew Dinn <adinn at redhat.com> wrote:
> > >>
> > >>
> > >>
> > >> On 26/10/2025 17:26, David Alayachew wrote:
> > >> > Also, here is the JLS 25 entry about escape sequences -- https://
> > >> > docs.oracle.com/javase/specs/jls/se25/html/jls-3.html#jls-3.10.7
> > >> > <
> https://docs.oracle.com/javase/specs/jls/se25/html/jls-3.html#jls-3.10.7>
> > >> >
> > >> > All I really want is for that to be added to the list, so that I
> can do
> > >> > it the same as I would in other languages. It sounds like an
> in-place
> > >> > replacement done by the compiler.
> > >>
> > >> What is wrong with using \u0007 or \7? (as documented in the html page
> > >> you cited).
> > >>
> > >> regards,
> > >>
> > >>
> > >> Andrew Dinn
> > >> -----------
> > >> Red Hat Distinguished Engineer
> > >> He/Him/His
> > >> IBM UK Limited
> > >> Registered in England and Wales with number 741598
> > >> Registered office: Building C, IBM Hursley Office, Hursley Park Road,
> > >> Winchester, Hampshire SO21 2JN
> > >>
>
>
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