Indenting Emacs Lisp only with tabs?

Indenting Emacs Lisp only with tabs?

[Elena]

Hello,

can you indent Emacs Lisp code only using tabs? I'd like to use a
proportional font, but that messes up indentation.

Thanks

Re: Indenting Emacs Lisp only with tabs?

[Peter Dyballa]

Am 02.09.2009 um 12:38 schrieb Elena:

> I'd like to use a proportional font, but that messes up indentation.


That's the trouble with proportional fonts...

--
Greetings

   Pete

Increase the size of your bike by at least *five* inches!

Re: Indenting Emacs Lisp only with tabs?

[Elena]

On 2 Set, 12:56, Peter Dyballa <Peter_Dyba...@Web.DE> wrote:
> Am 02.09.2009 um 12:38 schrieb Elena:
>
> > I'd like to use a proportional font, but that messes up indentation.
>
> That's the trouble with proportional fonts...

Well, that's a trouble with editors - like Emacs - where you can't
move characters with pixel precision.

However, if the indenting function does not try to overcome editor's
limitations by adding spaces to line things up, tabs work quite well.

IMO, proportional fonts are way more readable, and they save space.

Re: Indenting Emacs Lisp only with tabs?

[Helmut Eller]

* Elena [2009-09-02 15:11+0200] writes:

> On 2 Set, 12:56, Peter Dyballa <Peter_Dyba...@Web.DE> wrote:
>> Am 02.09.2009 um 12:38 schrieb Elena:
>>
>> > I'd like to use a proportional font, but that messes up indentation.
>>
>> That's the trouble with proportional fonts...
>
> Well, that's a trouble with editors - like Emacs - where you can't
> move characters with pixel precision.

To me it seems more like a limitation of text files.

> However, if the indenting function does not try to overcome editor's
> limitations by adding spaces to line things up, tabs work quite well.

You can set tab-width to 1 and the indent function will only insert
tabs.  It's more common though, to not use tabs at all by disabling
indent-tab-mode.

However, the indent function doesn't control how existing files are
displayed and that's the trouble with proportional fonts: code that uses
tabs and spaces looks messed up.

Helmut

Re: Indenting Emacs Lisp only with tabs?

[Elena]

On 2 Set, 13:35, Helmut Eller <eller.hel...@gmail.com> wrote:
> * Elena [2009-09-02 15:11+0200] writes:
>
> > On 2 Set, 12:56, Peter Dyballa <Peter_Dyba...@Web.DE> wrote:
> >> Am 02.09.2009 um 12:38 schrieb Elena:
>
> >> > I'd like to use a proportional font, but that messes up indentation.
>
> >> That's the trouble with proportional fonts...
>
> > Well, that's a trouble with editors - like Emacs - where you can't
> > move characters with pixel precision.
>
> To me it seems more like a limitation of text files.
>
> > However, if the indenting function does not try to overcome editor's
> > limitations by adding spaces to line things up, tabs work quite well.
>
> You can set tab-width to 1 and the indent function will only insert
> tabs.  It's more common though, to not use tabs at all by disabling
> indent-tab-mode.

That works, thanks.

Besides tab-width, I've set every variable in "Lisp indent" group to
4, 'lisp-indent-offset' and 'lisp-body-indent' to 4 too, and code now
gets indented as I wished.

Re: Indenting Emacs Lisp only with tabs?

[Oliver Scholz]

Helmut Eller <eller.helmut@gmail.com> writes:

> * Elena [2009-09-02 15:11+0200] writes:
>
>> On 2 Set, 12:56, Peter Dyballa <Peter_Dyba...@Web.DE> wrote:
>>> Am 02.09.2009 um 12:38 schrieb Elena:
>>>
>>> > I'd like to use a proportional font, but that messes up indentation.
>>>
>>> That's the trouble with proportional fonts...
>>
>> Well, that's a trouble with editors - like Emacs - where you can't
>> move characters with pixel precision.
>
> To me it seems more like a limitation of text files.
>
>> However, if the indenting function does not try to overcome editor's
>> limitations by adding spaces to line things up, tabs work quite well.
>
> You can set tab-width to 1 and the indent function will only insert
> tabs.  It's more common though, to not use tabs at all by disabling
> indent-tab-mode.

Not a good idea, though, if anybody else (including a future self which
uses a different editor) is ever supposed to read that code.

> However, the indent function doesn't control how existing files are
> displayed and that's the trouble with proportional fonts: code that uses
> tabs and spaces looks messed up.

I actually thought about this some time ago. I believe it would be
possible, not really complicated even, to fix this. Emacs could simply
put a display property with the value

`(space :align-to <number of whitespace chars from line beginning to first non-whitespace>)

on the leading space or tab characters on each line. And there you go:
proportional fonts with flawless indentation.

The only complication would be that font-lock does not naturally handle
the `display' property; but if my memory serves well, all the necessary
mechanics are in place and this would only be a minor obstacle.


    Oliver
-- 
16 Fructidor an 217 de la Révolution
Liberté, Egalité, Fraternité!

Re: Indenting Emacs Lisp only with tabs?

[Oliver Scholz]

Following up on myself ...

I don't follow the discussion on 'elastic tabstops'. Whatever makes one
happy, I guess.

However with regard to using proportional fonts for programming modes in
Emacs, I wrote:

[...]
> I actually thought about this some time ago. I believe it would be
> possible, not really complicated even, to fix this. Emacs could simply
> put a display property with the value
>
> `(space :align-to <number of whitespace chars from line beginning to first non-whitespace>)
>
> on the leading space or tab characters on each line. And there you go:
> proportional fonts with flawless indentation.
>
> The only complication would be that font-lock does not naturally handle
> the `display' property; but if my memory serves well, all the necessary
> mechanics are in place and this would only be a minor obstacle.

The proof-of-concept turns out to be quite trivial. I am putting it
here, in case anybody actually wants to play with it. The following
assumes that indentation consists only of space characters.


(defconst propindent-font-lock-keywords
  `(("^ +"
     (0 (progn (propindent-fix-whitespace (match-beginning 0) (match-end 0))
               nil)))))

(defun propindent-fix-whitespace (from to)
  (put-text-property from to 'display `(space :align-to ,(- to from))))

(defun propindent-spice-up-font-lock ()
  (add-to-list 'font-lock-extra-managed-props
               'display)
  (font-lock-add-keywords nil propindent-font-lock-keywords))


One Problem is, that this fixes indentation only relative to the
*beginning* of the previous line. So, if you have for instance a typical
`let' expression in Lisp, the clauses starting from the second one would
be lined up vertically, but the first one on line with the "let" would
not. To fix this, the function would have to check for the pixel
position of the corresponding character on the previous line and fix the
visible indentation accordingly. It seems that the :align-to property
may take a pixel value; unfortunately I am not aware of any way to check
for the pixel position of a character position in a window. There are
drawbacks, anyways: since proportional fonts in general take
considerably less horizontal space, fixing this would actually reduce
visible indentation.


    Oliver
-- 
18 Fructidor an 217 de la Révolution
Liberté, Egalité, Fraternité!

Re: Indenting Emacs Lisp only with tabs?

[Elena]

On 4 Set, 05:51, Oliver Scholz <alkibia...@gmx.de> wrote:
> There are
> drawbacks, anyways: since proportional fonts in general take
> considerably less horizontal space, fixing this would actually reduce
> visible indentation.

I've just incremented indentation width to work around that (from 4 to
8).

Re: Indenting Emacs Lisp only with tabs?

[Oliver Scholz]

Elena <egarrulo@gmail.com> writes:

> On 4 Set, 05:51, Oliver Scholz <alkibia...@gmx.de> wrote:
>> There are
>> drawbacks, anyways: since proportional fonts in general take
>> considerably less horizontal space, fixing this would actually reduce
>> visible indentation.
>
> I've just incremented indentation width to work around that (from 4 to
> 8).

Actually, I was just talking about the case of context-sensitive
aligning to the exact pixel position of a character on a previous line.
Such as the variable clauses in a `let' form in Lisp, or aligning
arguments to a function that are on different lines. Incrementing
indentation won't change anything there.

Whether it matters or not, I don't know. I'd like to have a function to
determin the pixel position of a character just so I could test whether
I like it or not.


    Oliver
-- 
18 Fructidor an 217 de la Révolution
Liberté, Egalité, Fraternité!

Re: Indenting Emacs Lisp only with tabs?

[Peter Dyballa]

Am 02.09.2009 um 15:11 schrieb Elena:

> Well, that's a trouble with editors - like Emacs - where you can't
> move characters with pixel precision.


You'd prefer to work in FontForge, xv, or GIMP?

--
Greetings

   Pete


"Evolution"            o           __o                     _o _
           °\___o      /0~         -\<,              ^\___ /=\\_/-%
oo~_______ /\ /\______/ \_________O/ O_______________o===>-->O--o____

Re: Indenting Emacs Lisp only with tabs?

[Elena]

On 2 Set, 14:06, Peter Dyballa <Peter_Dyba...@Web.DE> wrote:
> Am 02.09.2009 um 15:11 schrieb Elena:
>
> > Well, that's a trouble with editors - like Emacs - where you can't
> > move characters with pixel precision.
>
> You'd prefer to work in FontForge, xv, or GIMP?

Oh no! It's just that Emacs was born as a console editor, and
therefore shares console's limitations.

For a glimpse of indentation with pixel precision, look here (Java
plugin required):

http://nickgravgaard.com/elastictabstops/

Re: Indenting Emacs Lisp only with tabs?

[Peter Dyballa]

Am 02.09.2009 um 16:25 schrieb Elena:

> For a glimpse of indentation with pixel precision, look here (Java
> plugin required):
>
> http://nickgravgaard.com/elastictabstops/


Well, I can't see it! My browser shows non-proportional fonts and a  
precision of positioning around ten or more pixels horizontally. At  
least for me, this vast spacing is nothing precise.

--
Greetings

   Pete

One cannot live by television, video games, top ten CDs, and dumb  
movies alone.
				– Amiri Baraka, 1999

Re: Indenting Emacs Lisp only with tabs?

[Elena]

On 2 Set, 15:15, Peter Dyballa <Peter_Dyba...@Web.DE> wrote:
> Am 02.09.2009 um 16:25 schrieb Elena:
>
> > For a glimpse of indentation with pixel precision, look here (Java
> > plugin required):
>
> >http://nickgravgaard.com/elastictabstops/
>
> Well, I can't see it! My browser shows non-proportional fonts and a  
> precision of positioning around ten or more pixels horizontally. At  
> least for me, this vast spacing is nothing precise.

Maybe something is not working with your Java plugin.

Well, here, into the applet, this demo code:

struct ipc_perm
{
	key_t	key;
	ushort	uid;	/* owner euid and egid	*/
	ushort	gid;	/* group id	*/
	ushort	cuid;	/* creator euid and egid	*/
	cell-missing		/* for test purposes	*/
	ushort	mode;	/* access modes	*/
	ushort	seq;	/* sequence number	*/
};

shows with a proportional font and comments are _perfectly_ aligned.
If you add characters to a variable name, all comments move to the
right to keep themselves _perfectly_ aligned. That would be achievable
in Emacs only with a monospaced font.

Re: Indenting Emacs Lisp only with tabs?

[Helmut Eller]

* Elena [2009-09-02 16:25+0200] writes:

> For a glimpse of indentation with pixel precision, look here (Java
> plugin required):
>
> http://nickgravgaard.com/elastictabstops/

The function prototype requires a tab after the opening paren:

int someDemoCode(	int fred,
	int wilma)
{

that looks ugly or is a severe restriction.

Helmut

Re: Indenting Emacs Lisp only with tabs?

[Joost Kremers]

Elena wrote:
> For a glimpse of indentation with pixel precision, look here (Java
> plugin required):
>
> http://nickgravgaard.com/elastictabstops/

huh? when i remove or insert a TAB, the text is jumping all over the place! how
could anyone *want* this?


-- 
Joost Kremers                                      joostkremers@yahoo.com
Selbst in die Unterwelt dringt durch Spalten Licht
EN:SiS(9)

Re: Indenting Emacs Lisp only with tabs?

[B Smith-Mannschott]

On Thu, Sep 3, 2009 at 10:11, Joost Kremers<joostkremers@yahoo.com> wrote:
> Elena wrote:
>> For a glimpse of indentation with pixel precision, look here (Java
>> plugin required):
>>
>> http://nickgravgaard.com/elastictabstops/
>
> huh? when i remove or insert a TAB, the text is jumping all over the place! how
> could anyone *want* this?

Of course it works differently than you are used to! That doesn't
automatically make it unusable.

One of the reasons we stick with monospaced fonts in programming is
because we like to play all sorts of clever tricks with vertical
alignment to visually group related things. (These tricks,
incidentally, are also why mixing tabs and spaces causes so much pain
much of the time.)

What's interesting about the elastic tab stops proposal is that it
allows for arbitrary fonts without killing the ability to communicate
by aligning related things vertically.

But, *of course* it requires different habits when laying out code. Of
course, an editor that supports it as well as emacs does mono-spaced
layout would include logic to insert hard tabs at the right places to
produce a pleasing layout, just as emacs inserts spaces to vertically
align the arguments of a mult-line procedure call.

I think it's a clever idea, and I do think I could learn to take
advantage of what it offers while minimizing the impact of its
downsides, just as I do now when I code in emacs.

// Ben

Re: Indenting Emacs Lisp only with tabs?

[Elena]

On 3 Set, 12:17, B Smith-Mannschott <bsmith.o...@gmail.com> wrote:
> One of the reasons we stick with monospaced fonts in programming is
> because we like to play all sorts of clever tricks with vertical
> alignment to visually group related things. (These tricks,
> incidentally, are also why mixing tabs and spaces causes so much pain
> much of the time.)

Indeed, what a mode means when it indents a line with N spaces is:
move this text under (N+1)th character of previous line. That could be
accomplished with proportional fonts, too. Modes use spaces for what
they do, not what they mean. That's why I don't think we will anything
like elastic tabstops in Emacs in the near future. Too much indenting
code depends on this low level assumption.

> But, *of course* it requires different habits when laying out code. Of
> course, an editor that supports it as well as emacs does mono-spaced
> layout would include logic to insert hard tabs at the right places to
> produce a pleasing layout, just as emacs inserts spaces to vertically
> align the arguments of a mult-line procedure call.

I think that could be eased by making tabs (that is: vertical
alignment) visible, just as I think modes for makefiles already do
(albeit not for alignment purposes).

> I think it's a clever idea, and I do think I could learn to take
> advantage of what it offers while minimizing the impact of its
> downsides, just as I do now when I code in emacs.

I agree.

Re: Indenting Emacs Lisp only with tabs?

[Joost Kremers]

B Smith-Mannschott wrote:
> On Thu, Sep 3, 2009 at 10:11, Joost Kremers<joostkremers@yahoo.com> wrote:
>> Elena wrote:
>>> For a glimpse of indentation with pixel precision, look here (Java
>>> plugin required):
>>>
>>> http://nickgravgaard.com/elastictabstops/
>>
>> huh? when i remove or insert a TAB, the text is jumping all over the place! how
>> could anyone *want* this?
>
> Of course it works differently than you are used to! That doesn't
> automatically make it unusable.

well, the thing that i don't like about it is that when i insert or delete a tab
or some text, not only text on the line i'm on moves, but text on other lines
moves as well. that's insanely annoying... 

> What's interesting about the elastic tab stops proposal is that it
> allows for arbitrary fonts without killing the ability to communicate
> by aligning related things vertically.

until someone who prefers monospaced fonts wants to look at your code...


-- 
Joost Kremers                                      joostkremers@yahoo.com
Selbst in die Unterwelt dringt durch Spalten Licht
EN:SiS(9)

Re: Indenting Emacs Lisp only with tabs?

[Elena]

On 3 Set, 20:46, Joost Kremers
> well, the thing that i don't like about it is that when i insert or delete a tab
> or some text, not only text on the line i'm on moves, but text on other lines
> moves as well. that's insanely annoying...

That's just a demo. It just shows that you don't need monospaced fonts
to keeps things aligned.

> until someone who prefers monospaced fonts wants to look at your code...

Well, better him than me ;-)