character syntax of linefeed?

character syntax of linefeed?

[Tobias C. Rittweiler]

Quoting 35.2.1 Table of Syntax Classes:

  -- Syntax class: whitespace character
     "Whitespace characters" (designated by ` ' or `-') separate symbols
     and words from each other.  [...]  Space, tab, newline and formfeed
     are classified as whitespace in almost all major modes.

However, if I open, say, an empty foo.el or foo.c file, press RET
and then M-: (list (string (char-before))
                   (string (char-syntax (char-before))))

I get ("
       " ">"), i.e. a syntax of type 'endcomment'.

This behaviour seems to go through 23,22, and 21, so it's definitively
not new. :-)

My question is, is the above paragraph just wrong? Can I count on it
being ">"? 

Additionally: It seems that CR has a syntax type of `symbol' since
version 22, but it was ">" on 21.

  -T.

Re: character syntax of linefeed?

[Andreas Schwab]

"Tobias C. Rittweiler" <tcr@freebits.de> writes:

> Quoting 35.2.1 Table of Syntax Classes:
>
>   -- Syntax class: whitespace character
>      "Whitespace characters" (designated by ` ' or `-') separate symbols
>      and words from each other.  [...]  Space, tab, newline and formfeed
>      are classified as whitespace in almost all major modes.
>
> However, if I open, say, an empty foo.el or foo.c file, press RET
> and then M-: (list (string (char-before))
>                    (string (char-syntax (char-before))))
>
> I get ("
>        " ">"), i.e. a syntax of type 'endcomment'.
>
> This behaviour seems to go through 23,22, and 21, so it's definitively
> not new. :-)
>
> My question is, is the above paragraph just wrong?

In which way does that contradict "almost all major modes"?

Andreas.

-- 
Andreas Schwab, schwab@linux-m68k.org
GPG Key fingerprint = 58CA 54C7 6D53 942B 1756  01D3 44D5 214B 8276 4ED5
"And now for something completely different."

Re: character syntax of linefeed?

[Tobias C. Rittweiler]

Andreas Schwab <schwab@linux-m68k.org> writes:

> "Tobias C. Rittweiler" <tcr@freebits.de> writes:
>
>> Quoting 35.2.1 Table of Syntax Classes:
>>
>>   -- Syntax class: whitespace character
>>      "Whitespace characters" (designated by ` ' or `-') separate symbols
>>      and words from each other.  [...]  Space, tab, newline and formfeed
>>      are classified as whitespace in almost all major modes.
>>
>> However, if I open, say, an empty foo.el or foo.c file, press RET
>> and then M-: (list (string (char-before))
>>                    (string (char-syntax (char-before))))
>>
>> I get ("
>>        " ">"), i.e. a syntax of type 'endcomment'.
>>
>> This behaviour seems to go through 23,22, and 21, so it's definitively
>> not new. :-)
>>
>> My question is, is the above paragraph just wrong?
>
> In which way does that contradict "almost all major modes"?

It seems to exclude most programming modes. If you can speak of "almost
all major modes" even though it excludes almost all programming modes,
probably depends on what you use Emacs for. Though I agree that "just
wrong" in my OP was worded too strong.

  -T.

Re: character syntax of linefeed?

[Stefan Monnier]

> However, if I open, say, an empty foo.el or foo.c file, press RET
> and then M-: (list (string (char-before))
>                    (string (char-syntax (char-before))))
> I get ("
>        " ">"), i.e. a syntax of type 'endcomment'.

Elisp has comments of the form ;...\n, so clearly LF needs to be an
end-comment marker.  The same will hold for any major mode where there
are comments that end at LF.

> Can I count on it being ">"? 

In Elisp mode, yes.  In general of course not: that's why we have
syntax-tables: so that its contents can be different in
different situations.


        Stefan

Re: character syntax of linefeed?

[A Soare]

> I get ("
>        " ">"), i.e. a syntax of type 'endcomment'.
> 
> This behaviour seems to go through 23,22, and 21, so it's definitively
> not new. 
> 
> My question is, is the above paragraph just wrong? Can I count on it
> being ">"? 

Emacs was conceived first of all to be convenient for lisp, and in lisp newline
means also end of comment.



Alin