* Re: Executing part of the code instead of another
2020-10-07 7:01 ` Christopher Dimech
@ 2020-10-07 7:13 ` Emanuel Berg via Users list for the GNU Emacs text editor
2020-10-07 7:20 ` Robert Pluim
` (3 subsequent siblings)
4 siblings, 0 replies; 23+ messages in thread
From: Emanuel Berg via Users list for the GNU Emacs text editor @ 2020-10-07 7:13 UTC (permalink / raw)
To: help-gnu-emacs
Christopher Dimech wrote:
> What can one use if there is an else branch with
> multiple commands, as I would like to use it.
if, cond, pcase...
--
underground experts united
http://user.it.uu.se/~embe8573
https://dataswamp.org/~incal
^ permalink raw reply [flat|nested] 23+ messages in thread* Re: Executing part of the code instead of another
2020-10-07 7:01 ` Christopher Dimech
2020-10-07 7:13 ` Emanuel Berg via Users list for the GNU Emacs text editor
@ 2020-10-07 7:20 ` Robert Pluim
2020-10-07 13:09 ` Christopher Dimech
2020-10-07 9:38 ` Gregory Heytings via Users list for the GNU Emacs text editor
` (2 subsequent siblings)
4 siblings, 1 reply; 23+ messages in thread
From: Robert Pluim @ 2020-10-07 7:20 UTC (permalink / raw)
To: Christopher Dimech; +Cc: help-gnu-emacs, moasenwood
>>>>> On Wed, 7 Oct 2020 09:01:00 +0200, Christopher Dimech <dimech@gmx.com> said:
Christopher> What can one use if there is an else branch with multiple commands, as I would
Christopher> like to use it.
From 'C-h f if'
if is a special form in `C source code'.
(if COND THEN ELSE...)
Probably introduced at or before Emacs version 1.1.
If COND yields non-nil, do THEN, else do ELSE...
Returns the value of THEN or the value of the last of the ELSE's.
=> THEN must be one expression, but ELSE... can be zero or more expressions.
If COND yields nil, and there are no ELSE's, the value is nil.
Robert
--
^ permalink raw reply [flat|nested] 23+ messages in thread* Re: Executing part of the code instead of another
2020-10-07 7:20 ` Robert Pluim
@ 2020-10-07 13:09 ` Christopher Dimech
2020-10-07 17:29 ` Nick Dokos
0 siblings, 1 reply; 23+ messages in thread
From: Christopher Dimech @ 2020-10-07 13:09 UTC (permalink / raw)
To: Robert Pluim; +Cc: help-gnu-emacs, moasenwood
I have tried executing the following condition (if (nb > na))
(setq na 2)
(setq nb 5)
( if (> nb na)
(message "nb > na [condition true]")
(message "condition false")
)
I highlighted the region then pressed C-x C-e
It returned the first message as expected, but when I tried
the next one, I still got the first message.
(setq na 2)
(setq nb 1)
( if (> nb na)
(message "nb > na [condition true]")
(message "condition false")
)
> Sent: Wednesday, October 07, 2020 at 9:20 AM
> From: "Robert Pluim" <rpluim@gmail.com>
> To: "Christopher Dimech" <dimech@gmx.com>
> Cc: moasenwood@zoho.eu, help-gnu-emacs@gnu.org
> Subject: Re: Executing part of the code instead of another
>
> >>>>> On Wed, 7 Oct 2020 09:01:00 +0200, Christopher Dimech <dimech@gmx.com> said:
>
> Christopher> What can one use if there is an else branch with multiple commands, as I would
> Christopher> like to use it.
>
> From 'C-h f if'
>
> if is a special form in `C source code'.
>
> (if COND THEN ELSE...)
>
> Probably introduced at or before Emacs version 1.1.
>
> If COND yields non-nil, do THEN, else do ELSE...
> Returns the value of THEN or the value of the last of the ELSE's.
> => THEN must be one expression, but ELSE... can be zero or more expressions.
> If COND yields nil, and there are no ELSE's, the value is nil.
>
>
> Robert
> --
>
^ permalink raw reply [flat|nested] 23+ messages in thread* Re: Executing part of the code instead of another
2020-10-07 13:09 ` Christopher Dimech
@ 2020-10-07 17:29 ` Nick Dokos
2020-10-07 18:01 ` Christopher Dimech
0 siblings, 1 reply; 23+ messages in thread
From: Nick Dokos @ 2020-10-07 17:29 UTC (permalink / raw)
To: help-gnu-emacs
Christopher Dimech <dimech@gmx.com> writes:
> I have tried executing the following condition (if (nb > na))
>
> (setq na 2)
> (setq nb 5)
> ( if (> nb na)
> (message "nb > na [condition true]")
> (message "condition false")
> )
>
> I highlighted the region then pressed C-x C-e
> It returned the first message as expected, but when I tried
> the next one, I still got the first message.
>
`C-x C-e` is bound to `eval-last-sexp` which evaluates the *last*
sexp: the if. It does not evaluate the setq's (setting the region does
*NOT* matter for it - try `M-x eval-region' for that)
> (setq na 2)
> (setq nb 1)
> ( if (> nb na)
> (message "nb > na [condition true]")
> (message "condition false")
> )
>
>
>
>
>> Sent: Wednesday, October 07, 2020 at 9:20 AM
>> From: "Robert Pluim" <rpluim@gmail.com>
>> To: "Christopher Dimech" <dimech@gmx.com>
>> Cc: moasenwood@zoho.eu, help-gnu-emacs@gnu.org
>> Subject: Re: Executing part of the code instead of another
>>
>> >>>>> On Wed, 7 Oct 2020 09:01:00 +0200, Christopher Dimech <dimech@gmx.com> said:
>>
>> Christopher> What can one use if there is an else branch with multiple commands, as I would
>> Christopher> like to use it.
>>
>> From 'C-h f if'
>>
>> if is a special form in `C source code'.
>>
>> (if COND THEN ELSE...)
>>
>> Probably introduced at or before Emacs version 1.1.
>>
>> If COND yields non-nil, do THEN, else do ELSE...
>> Returns the value of THEN or the value of the last of the ELSE's.
>> => THEN must be one expression, but ELSE... can be zero or more expressions.
>> If COND yields nil, and there are no ELSE's, the value is nil.
>>
>>
>> Robert
>> --
>>
>
>
--
Nick
"There are only two hard problems in computer science: cache
invalidation, naming things, and off-by-one errors." -Martin Fowler
^ permalink raw reply [flat|nested] 23+ messages in thread
* Re: Executing part of the code instead of another
2020-10-07 17:29 ` Nick Dokos
@ 2020-10-07 18:01 ` Christopher Dimech
0 siblings, 0 replies; 23+ messages in thread
From: Christopher Dimech @ 2020-10-07 18:01 UTC (permalink / raw)
To: Nick Dokos; +Cc: help-gnu-emacs
Noted Nick. Thank you.
---------------------
Christopher Dimech
Chief Administrator - Naiad Informatics - GNU Project (Geocomputation)
- Geophysical Simulation
- Geological Subsurface Mapping
- Disaster Preparedness and Mitigation
- Natural Resource Exploration and Production
- Free Software Advocacy
> Sent: Wednesday, October 07, 2020 at 7:29 PM
> From: "Nick Dokos" <ndokos@gmail.com>
> To: help-gnu-emacs@gnu.org
> Subject: Re: Executing part of the code instead of another
>
> Christopher Dimech <dimech@gmx.com> writes:
>
> > I have tried executing the following condition (if (nb > na))
> >
> > (setq na 2)
> > (setq nb 5)
> > ( if (> nb na)
> > (message "nb > na [condition true]")
> > (message "condition false")
> > )
> >
> > I highlighted the region then pressed C-x C-e
> > It returned the first message as expected, but when I tried
> > the next one, I still got the first message.
> >
> `C-x C-e` is bound to `eval-last-sexp` which evaluates the *last*
> sexp: the if. It does not evaluate the setq's (setting the region does
> *NOT* matter for it - try `M-x eval-region' for that)
>
>
> > (setq na 2)
> > (setq nb 1)
> > ( if (> nb na)
> > (message "nb > na [condition true]")
> > (message "condition false")
> > )
> >
> >
> >
> >
> >> Sent: Wednesday, October 07, 2020 at 9:20 AM
> >> From: "Robert Pluim" <rpluim@gmail.com>
> >> To: "Christopher Dimech" <dimech@gmx.com>
> >> Cc: moasenwood@zoho.eu, help-gnu-emacs@gnu.org
> >> Subject: Re: Executing part of the code instead of another
> >>
> >> >>>>> On Wed, 7 Oct 2020 09:01:00 +0200, Christopher Dimech <dimech@gmx.com> said:
> >>
> >> Christopher> What can one use if there is an else branch with multiple commands, as I would
> >> Christopher> like to use it.
> >>
> >> From 'C-h f if'
> >>
> >> if is a special form in `C source code'.
> >>
> >> (if COND THEN ELSE...)
> >>
> >> Probably introduced at or before Emacs version 1.1.
> >>
> >> If COND yields non-nil, do THEN, else do ELSE...
> >> Returns the value of THEN or the value of the last of the ELSE's.
> >> => THEN must be one expression, but ELSE... can be zero or more expressions.
> >> If COND yields nil, and there are no ELSE's, the value is nil.
> >>
> >>
> >> Robert
> >> --
> >>
> >
> >
>
> --
> Nick
>
> "There are only two hard problems in computer science: cache
> invalidation, naming things, and off-by-one errors." -Martin Fowler
>
>
>
^ permalink raw reply [flat|nested] 23+ messages in thread
* Re: Executing part of the code instead of another
2020-10-07 7:01 ` Christopher Dimech
2020-10-07 7:13 ` Emanuel Berg via Users list for the GNU Emacs text editor
2020-10-07 7:20 ` Robert Pluim
@ 2020-10-07 9:38 ` Gregory Heytings via Users list for the GNU Emacs text editor
2020-10-07 9:46 ` Emanuel Berg via Users list for the GNU Emacs text editor
2020-10-07 15:15 ` Drew Adams
2020-10-18 23:02 ` Douglas Lewan
4 siblings, 1 reply; 23+ messages in thread
From: Gregory Heytings via Users list for the GNU Emacs text editor @ 2020-10-07 9:38 UTC (permalink / raw)
To: Christopher Dimech; +Cc: moasenwood, help-gnu-emacs
>
> What can one use if there is an else branch with multiple commands, as I
> would like to use it.
>
In general you can do:
(if [condition]
(progn
[multiple statements of the "then" part])
[multiple statements of the "else" part"])
^ permalink raw reply [flat|nested] 23+ messages in thread* Re: Executing part of the code instead of another
2020-10-07 9:38 ` Gregory Heytings via Users list for the GNU Emacs text editor
@ 2020-10-07 9:46 ` Emanuel Berg via Users list for the GNU Emacs text editor
2020-10-07 9:53 ` Robert Pluim
2020-10-07 13:48 ` Christopher Dimech
0 siblings, 2 replies; 23+ messages in thread
From: Emanuel Berg via Users list for the GNU Emacs text editor @ 2020-10-07 9:46 UTC (permalink / raw)
To: help-gnu-emacs
Gregory Heytings via Users list for the GNU Emacs text editor wrote:
> In general you can do:
>
> (if [condition]
> (progn
> [multiple statements of the "then" part])
> [multiple statements of the "else" part"])
And the value returned, if condition, is the one of
the last one in the "then" or progn part - the
nth one!
There is also a `prog1'!
But no prog2 :(
--
underground experts united
http://user.it.uu.se/~embe8573
https://dataswamp.org/~incal
^ permalink raw reply [flat|nested] 23+ messages in thread
* Re: Executing part of the code instead of another
2020-10-07 9:46 ` Emanuel Berg via Users list for the GNU Emacs text editor
@ 2020-10-07 9:53 ` Robert Pluim
2020-10-07 11:17 ` Emanuel Berg via Users list for the GNU Emacs text editor
2020-10-07 13:28 ` Stefan Monnier
2020-10-07 13:48 ` Christopher Dimech
1 sibling, 2 replies; 23+ messages in thread
From: Robert Pluim @ 2020-10-07 9:53 UTC (permalink / raw)
To: help-gnu-emacs
>>>>> On Wed, 07 Oct 2020 11:46:02 +0200, Emanuel Berg via Users list for the GNU Emacs text editor <help-gnu-emacs@gnu.org> said:
Emanuel> Gregory Heytings via Users list for the GNU Emacs text editor wrote:
>> In general you can do:
>>
>> (if [condition]
>> (progn
>> [multiple statements of the "then" part])
>> [multiple statements of the "else" part"])
Emanuel> And the value returned, if condition, is the one of
Emanuel> the last one in the "then" or progn part - the
Emanuel> nth one!
Emanuel> There is also a `prog1'!
Emanuel> But no prog2 :(
? I see a prog2 macro in subr.el (it used to be a function, going back
to at least 1994).
Robert
--
^ permalink raw reply [flat|nested] 23+ messages in thread* Re: Executing part of the code instead of another
2020-10-07 9:46 ` Emanuel Berg via Users list for the GNU Emacs text editor
2020-10-07 9:53 ` Robert Pluim
@ 2020-10-07 13:48 ` Christopher Dimech
2020-10-07 14:01 ` tomas
1 sibling, 1 reply; 23+ messages in thread
From: Christopher Dimech @ 2020-10-07 13:48 UTC (permalink / raw)
To: moasenwood; +Cc: help-gnu-emacs
It would be better if you explain to me this progn stuff
Have tried an example like this
(setq na 8)
(setq nb 13)
( if (> nb na)
progn (
(message "nb > na condition [condition is true]")
(message "nb > na condition [condition is true]")
)
progn (
(message "condition false")
(message "condition false")
)
)
> Sent: Wednesday, October 07, 2020 at 11:46 AM
> From: "Emanuel Berg via Users list for the GNU Emacs text editor" <help-gnu-emacs@gnu.org>
> To: help-gnu-emacs@gnu.org
> Subject: Re: Executing part of the code instead of another
>
> Gregory Heytings via Users list for the GNU Emacs text editor wrote:
>
> > In general you can do:
> >
> > (if [condition]
> > (progn
> > [multiple statements of the "then" part])
> > [multiple statements of the "else" part"])
>
> And the value returned, if condition, is the one of
> the last one in the "then" or progn part - the
> nth one!
>
> There is also a `prog1'!
>
> But no prog2 :(
>
> --
> underground experts united
> http://user.it.uu.se/~embe8573
> https://dataswamp.org/~incal
>
>
>
^ permalink raw reply [flat|nested] 23+ messages in thread* Re: Executing part of the code instead of another
2020-10-07 13:48 ` Christopher Dimech
@ 2020-10-07 14:01 ` tomas
2020-10-07 14:05 ` Christopher Dimech
0 siblings, 1 reply; 23+ messages in thread
From: tomas @ 2020-10-07 14:01 UTC (permalink / raw)
To: Christopher Dimech; +Cc: help-gnu-emacs, moasenwood
[-- Attachment #1: Type: text/plain, Size: 928 bytes --]
On Wed, Oct 07, 2020 at 03:48:51PM +0200, Christopher Dimech wrote:
> It would be better if you explain to me this progn stuff
>
> Have tried an example like this
>
> (setq na 8)
> (setq nb 13)
> ( if (> nb na)
> progn (
> (message "nb > na condition [condition is true]")
> (message "nb > na condition [condition is true]")
> )
No. Written in Lisp, it's
(progn
(thing 1)
(thing 2)
...)
In C (and in conventional maths, you'd write it as you did
above).
Note that it's the same way as you write (message "foo")
[you don't write message("foo"), as you'd do in C or
Python or what not).
Progn is a form to bundle a sequence of forms, which are
evaluated one after the other. The value of progn is
that of the last form evaluated (that's the -n), as opposed
to prog1, which would do the same as progn, but return the
value of its first form.
Cheers
- t
[-- Attachment #2: Digital signature --]
[-- Type: application/pgp-signature, Size: 198 bytes --]
^ permalink raw reply [flat|nested] 23+ messages in thread* Re: Executing part of the code instead of another
2020-10-07 14:01 ` tomas
@ 2020-10-07 14:05 ` Christopher Dimech
2020-10-08 17:43 ` Leo Butler
0 siblings, 1 reply; 23+ messages in thread
From: Christopher Dimech @ 2020-10-07 14:05 UTC (permalink / raw)
To: tomas; +Cc: help-gnu-emacs, moasenwood
Thank you so very much Tomas. Ok. Got It.
> Sent: Wednesday, October 07, 2020 at 4:01 PM
> From: tomas@tuxteam.de
> To: "Christopher Dimech" <dimech@gmx.com>
> Cc: moasenwood@zoho.eu, help-gnu-emacs@gnu.org
> Subject: Re: Executing part of the code instead of another
>
> On Wed, Oct 07, 2020 at 03:48:51PM +0200, Christopher Dimech wrote:
> > It would be better if you explain to me this progn stuff
> >
> > Have tried an example like this
> >
> > (setq na 8)
> > (setq nb 13)
> > ( if (> nb na)
> > progn (
> > (message "nb > na condition [condition is true]")
> > (message "nb > na condition [condition is true]")
> > )
>
> No. Written in Lisp, it's
>
> (progn
> (thing 1)
> (thing 2)
> ...)
>
> In C (and in conventional maths, you'd write it as you did
> above).
>
> Note that it's the same way as you write (message "foo")
> [you don't write message("foo"), as you'd do in C or
> Python or what not).
>
> Progn is a form to bundle a sequence of forms, which are
> evaluated one after the other. The value of progn is
> that of the last form evaluated (that's the -n), as opposed
> to prog1, which would do the same as progn, but return the
> value of its first form.
>
> Cheers
> - t
>
^ permalink raw reply [flat|nested] 23+ messages in thread* Re: Executing part of the code instead of another
2020-10-07 14:05 ` Christopher Dimech
@ 2020-10-08 17:43 ` Leo Butler
0 siblings, 0 replies; 23+ messages in thread
From: Leo Butler @ 2020-10-08 17:43 UTC (permalink / raw)
To: help-gnu-emacs
Christopher Dimech <dimech@gmx.com> writes:
> Thank you so very much Tomas. Ok. Got It.
>
>
>> Sent: Wednesday, October 07, 2020 at 4:01 PM
>> From: tomas@tuxteam.de
>> To: "Christopher Dimech" <dimech@gmx.com>
>> Cc: moasenwood@zoho.eu, help-gnu-emacs@gnu.org
>> Subject: Re: Executing part of the code instead of another
>>
>> On Wed, Oct 07, 2020 at 03:48:51PM +0200, Christopher Dimech wrote:
>> > It would be better if you explain to me this progn stuff
>> >
>> > Have tried an example like this
>> >
>> > (setq na 8)
>> > (setq nb 13)
>> > ( if (> nb na)
>> > progn (
>> > (message "nb > na condition [condition is true]")
>> > (message "nb > na condition [condition is true]")
>> > )
>>
>> No. Written in Lisp, it's
>>
>> (progn
>> (thing 1)
>> (thing 2)
>> ...)
>>
Note that Emacs has its own repl, too.
M-x ielm RET
Take a while to learn how to think in lisp. The constructs you are using
are C-like and very primitive (non-expressive, if you prefer) compared
to what you can do in lisp.
Specifically, it seems like what you are trying to do is usually
accomplished with minor-modes in elisp.
Leo
^ permalink raw reply [flat|nested] 23+ messages in thread
* RE: Executing part of the code instead of another
2020-10-07 7:01 ` Christopher Dimech
` (2 preceding siblings ...)
2020-10-07 9:38 ` Gregory Heytings via Users list for the GNU Emacs text editor
@ 2020-10-07 15:15 ` Drew Adams
2020-10-18 23:02 ` Douglas Lewan
4 siblings, 0 replies; 23+ messages in thread
From: Drew Adams @ 2020-10-07 15:15 UTC (permalink / raw)
To: Christopher Dimech, moasenwood; +Cc: help-gnu-emacs
> What can one use if there is an else branch with multiple commands, as I
> would like to use it.
Please consider asking Emacs:
`C-h i', choose `Emacs Lisp Intro', and start
learning about Emacs Lisp.
`i conditional RET' looks up "conditional" in
the index and takes you to the first index entry.
`,' takes you to other entries.
^ permalink raw reply [flat|nested] 23+ messages in thread* Re: Executing part of the code instead of another
2020-10-07 7:01 ` Christopher Dimech
` (3 preceding siblings ...)
2020-10-07 15:15 ` Drew Adams
@ 2020-10-18 23:02 ` Douglas Lewan
4 siblings, 0 replies; 23+ messages in thread
From: Douglas Lewan @ 2020-10-18 23:02 UTC (permalink / raw)
To: help-gnu-emacs
(cond) is what comes to my mind for such a thing.
On 10/7/20 3:01 AM, Christopher Dimech wrote:
> What can one use if there is an else branch with multiple commands, as I would
> like to use it.
>
>
>> Sent: Wednesday, October 07, 2020 at 3:05 AM
>> From: "Emanuel Berg via Users list for the GNU Emacs text editor" <help-gnu-emacs@gnu.org>
>> To: help-gnu-emacs@gnu.org
>> Subject: Re: Executing part of the code instead of another
>>
>> Christopher Dimech wrote:
>>
>>> I have been trying to do the following
>>>
>>> (setq optn 1)
>>> (if (= optn 1)
>>>
>>> ( global-unset-key (kbd "C-<home>") )
>>> [...]
>>> ( global-set-key (kbd "C-<mouse-5>")
>>> (lambda () (interactive) (scroll-up 1)) ; Scrolls the page Up
>>> )
>>> )
>> If there is no else branch, use `when' (or `unless').
>>
>> (when (= var-a 1)
>> (do-this)
>> (and-this)
>> (and-this-as-well) )
>>
>> --
>> underground experts united
>> http://user.it.uu.se/~embe8573
>> https://dataswamp.org/~incal
>>
>>
>>
--
,Doug
d.lewan2000@gmail.com
(908) 720 7908
You know, it's amazing how much closer to 0 that 8 067 332 is than 15 is. (2020 Oct 18)
^ permalink raw reply [flat|nested] 23+ messages in thread