Re: Making alist that executes multiple commands

[Heime via Users list for the GNU Emacs text editor <help-gnu-emacs@gnu.org>]

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On Tuesday, November 26th, 2024 at 11:11 AM, Stephen Berman <stephen.berman@gmx.net> wrote:

> On Mon, 25 Nov 2024 22:50:03 +0000 Heime heimeborgia@protonmail.com wrote:
> 
> > Sent with Proton Mail secure email.
> > 
> > On Tuesday, November 26th, 2024 at 10:09 AM, Stephen Berman
> > stephen.berman@gmx.net wrote:
> > 
> > > On Mon, 25 Nov 2024 21:59:53 +0000 Heime heimeborgia@protonmail.com wrote:
> > > 
> > > > About your comment
> > > > 
> > > > > That seems fine if the functions take no arguments, though probably not
> > > > > as flexible as looping over a list.
> > > > 
> > > > You provided the examples
> > > > 
> > > > (funcall 'alkotr-ar ar)
> > > > (funcall 'alkotr-ar af)
> > > > 
> > > > But I did not understand how to inceorporate this idea. With
> > > > my lambda function, I can also pass arguments to my commands.
> > > > 
> > > > I did not understand the implication of the following in my case.
> > > > 
> > > > (dolist (f '(+ - list))
> > > > (dolist (a '(1 2 3))
> > > > (funcall f a)))
> > > > 
> > > > Thusly, I do not understand what "allow arguments to be freely combined"
> > > > actually means practically.
> > > 
> > > It produces all combinations of function calls comprised of one of the
> > > functions f and one of the arguments a; I did not mean to imply anything
> > > else. If it doesn't help with your use case, then of course don't use
> > > it.
> > 
> > I worked through it a little bit
> > 
> > (dolist (f '(+ - list))
> > (dolist (a '(1 2 3))
> > (funcall f a)))
> > 
> > Which fails for + and -, Elisp requires at least two arguments
> > to perform arithmetic operations. Since only a single argument
> > is provided, this will result in an error.
> 
> 
> The functions `+' and` -' take any number of numbers (including none).
> I don't know why you got an error; I don't:
> 
> (let (ret)
> (dolist (f '(+ - list))
> (dolist (a '(1 2 3))
> (push (funcall f a) ret)))
> ret)
> ==>
> 
> ((3) (2) (1) -3 -2 -1 3 2 1)

You are quite right.  I saw nil and thought it failed.  It did not
after doing

(dolist (f '(+ - list))
  (dolist (a '(1 2 3))
    (message "Result of %s: %s" f (funcall f a )) ))


 
> [...]
> 
> > I just have a set of commands that I want to run according to some setting
> > 'argm or 'go. Or do both with '(argm go). That's all. I think the lamdba
> > gets this done. The arguments to any of the commands in the lambda can come
> > from external settings as well right, global variables and can introduce
> > conditionals as well. Which should be what I require. Or would you know
> > about something else. Is there ways the implementation can break?
> 
> 
> I already said if it does what you want, that's fine. I can't prove for
> you it will always work, so if you find a case where it doesn't work,
> feel free to show it. Until then, I think this discussion has run its
> course.
> 
> Steve Berman

Right, I now understand the mixing of list of arguments with a list
of function names.  Such mixing is not what I had in mind.  Just wanted
a set a commands in a function which is not defined externally.