function Qs

function Qs

[Dan Bensen]

Hi everybody.  I have two questions, please:

1. It looks like set-mark-command and indent-region take arguments
when called from another function.  Where's the documentation for
Emacs function signatures?  They don't seem to be in the Emacs manual.

2. beginning-of-buffer, end-of-line, etc. all move point to the
specified position.  Are there equivalent functions that return
the value of the corresponding position without side effects?

-- 
Dan
www.prairienet.org/~dsb

Re: function Qs

[weber]

On 24 fev, 18:07, Dan Bensen <randomg...@cyberspace.net> wrote:
> Hi everybody.  I have two questions, please:
>
> 1. It looks like set-mark-command and indent-region take arguments
> when called from another function.  Where's the documentation for
> Emacs function signatures?  They don't seem to be in the Emacs manual.
>
> 2. beginning-of-buffer, end-of-line, etc. all move point to the
> specified position.  Are there equivalent functions that return
> the value of the corresponding position without side effects?
>
> --
> Danwww.prairienet.org/~dsb

1. Documentation for functions is easily accessed with Control-h f and
then enter the name of the function.

2. You can always do a "save-excursion" before calling those
functions... check it with C-h f as well.

Maybe it would be better if you told us what to you want to
accomplish... there might be an easier way.

Cheers,
weber

Re: function Qs

[Dan Bensen]

weber wrote:
> 1. Documentation for functions is easily accessed with Control-h f and
> then enter the name of the function.
Very nice.  Thank you.

> Maybe it would be better if you told us what to you want to
> accomplish... there might be an easier way.

Nah, that's no fun* :)  The current problem isn't nearly as important as 
the general learning experience.

According to the help section for end-of-buffer,
point-max is the equivalent function I'm looking for.
Are there more functions like this?  point-min?  point-end-of-line?  I 
don't see them documented.

The help section for set-mark says to define your own variable instead 
of using mark:
    (let ((beg (point))) (forward-line 1) (delete-region beg (point)))

With return values, this could be written something like
    (delete-region (point) (point-next-line))

So it sounds like changing point is standard procedure, but changing 
mark is discouraged?

*This is what I've been trying to do (it seems to work now):
(defun indent-buffer ()
   (interactive)
   (indent-region 1 (point-max) nil))

-- 
Dan
www.prairienet.org/~dsb

RE: function Qs

[Drew Adams]

> Are there more functions like this?  point-min?  point-end-of-line?  I
> don't see them documented.

M-x apropos point

Command `apropos' is your friend.

The Elisp manual, not the Emacs manual, is the reference for Emacs-Lisp
code. All of the functions you have asked about are explained there. Both
manuals are available via `C-h i'.

> So it sounds like changing point is standard procedure, but changing
> mark is discouraged?

Correct. Actually, both are discouraged if the user doesn't expect any
change. To move point temporarily to obtain a location, wrap the movement in
`save-excursion'.

Again, this is explained in the Elisp manual.

> *This is what I've been trying to do (it seems to work now):
> (defun indent-buffer ()
>    (interactive)
>    (indent-region 1 (point-max) nil))

(point-min), not 1.

Re: function Qs

[Matthew Flaschen]

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Drew Adams wrote:
>> Are there more functions like this?  point-min?  point-end-of-line?  I
>> don't see them documented.
> 
> M-x apropos point
> 
> Command `apropos' is your friend.
> 
> The Elisp manual, not the Emacs manual, is the reference for Emacs-Lisp
> code. All of the functions you have asked about are explained there. Both
> manuals are available via `C-h i'.

I searched apropos for point, and I can't find a point-end-of-line or
equivalent.  Is there such a function?  If not, do you know a way I
could get the full text of the current line?

Matthew Flaschen


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Re: function Qs

[Matthew Flaschen]

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Matthew Flaschen wrote:
> Drew Adams wrote:
>>> Are there more functions like this?  point-min?  point-end-of-line?  I
>>> don't see them documented.
>> M-x apropos point
>>
>> Command `apropos' is your friend.
>>
>> The Elisp manual, not the Emacs manual, is the reference for Emacs-Lisp
>> code. All of the functions you have asked about are explained there. Both
>> manuals are available via `C-h i'.
> 
> I searched apropos for point, and I can't find a point-end-of-line or
> equivalent.  Is there such a function?  If not, do you know a way I
> could get the full text of the current line?

I figured it out:
(buffer-substring-no-properties (line-beginning-position)
(line-end-position))

Is there a neater way?

Matt Flaschen


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Re: function Qs

[james]

On Feb 24, 9:19 pm, Matthew Flaschen <matthew.flasc...@gatech.edu>
wrote:
>
> I searched apropos for point, and I can't find a point-end-of-line or
> equivalent.  Is there such a function?  If not, do you know a way I
> could get the full text of the current line?
>
> Matthew Flaschen

apropos only searches interactive functions (those that can be called
by M-x) by default... but if you give it a parameter:

C-u C-h a point

(I just discovered this myself by: C-h f apropos)

Looks like what you're looking for is point-at-bol and point-at-eol:

(setq line-string
   (buffer-substring (point-at-bol) (point-at-eol)))

Re: function Qs

[Matthew Flaschen]

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james wrote:
> On Feb 24, 9:19 pm, Matthew Flaschen <matthew.flasc...@gatech.edu>
> wrote:
>> I searched apropos for point, and I can't find a point-end-of-line or
>> equivalent.  Is there such a function?  If not, do you know a way I
>> could get the full text of the current line?
>>
>> Matthew Flaschen
> 
> apropos only searches interactive functions (those that can be called
> by M-x) by default... but if you give it a parameter:

Yes, I figured that out myself, and just changed it by setting
apropos-do-all (non-interactive functions are kind of important when
you're coding elisp).

> Looks like what you're looking for is point-at-bol and point-at-eol:
> 
> (setq line-string
>    (buffer-substring (point-at-bol) (point-at-eol)))

Thanks, I ended up using the unaliased versions of those (however, that
method will copy text properties into the string, which may not be what
you want).

Matthew Flaschen


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RE: function Qs

[Drew Adams]

> apropos only searches interactive functions (those that can be called
> by M-x) by default... but if you give it a parameter:
> C-u C-h a point
> (I just discovered this myself by: C-h f apropos)
> Looks like what you're looking for is point-at-bol and point-at-eol:

Absolutely untrue. `C-h f apropos' gives this:

 Show all meaningful Lisp symbols whose names match PATTERN.
 Symbols are shown if they are defined as functions, variables, or
 faces, or if they have nonempty property lists....

Both `point-at-bol' and `point-at-eol' are listed with `M-x apropos'.

Using `C-u' with `apropos', or setting `apropos-do-all' to non-nil gives you
info about *all* symbols, not just "functions, variables, or faces,..." But
all functions are treated by `apropos' even without `C-u'.

Do not confuse `C-h a', which is bound to command `apropos-command', with
command `apropos'. There are other apropos commands as well: `C-h a
apropos'.

Re: function Qs

[Matthew Flaschen]

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Drew Adams wrote:
>> apropos only searches interactive functions (those that can be called
>> by M-x) by default... but if you give it a parameter:
>> C-u C-h a point
>> (I just discovered this myself by: C-h f apropos)
>> Looks like what you're looking for is point-at-bol and point-at-eol:
> 
> Absolutely untrue. `C-h f apropos' gives this:

Yes, but C-h f apropros-command gives:

Show commands (interactively callable functions) that match APROPOS-REGEXP.
With optional prefix DO-ALL, or if `apropos-do-all' is non-nil, also
show noninteractive functions.

> Do not confuse `C-h a', which is bound to command `apropos-command', with
> command `apropos'. There are other apropos commands as well: `C-h a
> apropos'.

Thanks, I never noticed that.  I just rebound C-h a to apropos.

Matthew Flaschen


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Re: function Qs

[Kevin Rodgers]

Matthew Flaschen wrote:
> Drew Adams wrote:
>> Do not confuse `C-h a', which is bound to command `apropos-command', with
>> command `apropos'. There are other apropos commands as well: `C-h a
>> apropos'.
> 
> Thanks, I never noticed that.  I just rebound C-h a to apropos.

You can have both:

(global-set-key "\C-hA" 'apropos)

-- 
Kevin Rodgers
Denver, Colorado, USA