Re: Making alist that executes multiple commands

[Stephen Berman <stephen.berman@gmx.net>]

On Mon, 25 Nov 2024 20:45:22 +0000 Heime <heimeborgia@protonmail.com> wrote:

>> > Would be good to allow arguments to be freely combined.
>> > But how does one loop over lists of these arguments from the
>> > code you posted?
>>
>>
>> Something like this, for example:
>>
>> (dolist (f '(+ - list))
>> (dolist (a '(1 2 3))
>> (funcall f a)))
>>
>> > I could have the following, but got some difficulties about
>> > how to execute each command with its arguments, in the way you
>> > suggest.
>> >
>> > (defun fpln-test (symbol-list)
>> > (let ( (lookup-alist '((ar ((alkotr-ar arg-this)
>> > (alkotr-af arg-that arg-other)))
>> > (go ((alkotr-go arg-dim)
>> > (alkotr-gc arg-dum arg-sum))) )) )
>> >
>> > (dolist (actm symbol-list)
>> > (let ((commands (cdr (assoc actm lookup-alist))))
>> > (while commands
>> > (dolist (cmd commands)
>> > (apply (car cmd) (cdr cmd)))
>> > (message "Key '%s' not found in lookup-alist" key))))))
>>
>>
>> When I wrote "using a list of function calls as the value of each alist
>> element seems reasonable" I was assuming you wanted them in lambda
>> expressions, where they are evaluated, as in the example you gave
>> previously. You can't use a function call as the first argument of
>> `apply' or` funcall' because a function call (which is just a list whose
>> first element is a function) is not a function.
>
> Have been trying to handle your suggestion not to use a lambda, but to
> handle the general case of executing a sequence of commands in a list,
> each element being a command to run.

Then you might try looping over lists of functions and arguments like in
the above schematic example I gave, though depending upon how you want
to combine the functions and arguments (e.g. if the functions don't all
have the same arity), this could become complicated.  But without
specific examples of what you want to do I can't give more specific
advice.

>> On Mon, 25 Nov 2024 17:59:22 +0000 Heime heimeborgia@protonmail.com wrote:
>>
>> > I get error when calling (marnap '(armg go))
>> >
>> > That is I get message "ACTM Unrecognised: 'armg"
>> >
>> > (defun marnap (&optional actm-service)
>> >
>> > (let ( (lookup-alist '((armg ((add-to-list 'load-path
>> > (marnap-sec-fpln-waypt "NAPLN"))
>> > (require 'napyon)))
>> >
>> > (go ((napyon 'go))) )) )
>> >
>> > (dolist (actm actm-service)
>> > (let ((fnlist (cdr (assoc actm lookup-alist))))
>> > (while fnlist
>> > (dolist (cmd fnlist)
>> > (if (functionp (car cmd))
>> > (apply (car cmd) (cdr cmd))
>> > (message "ACTM Unrecognised: '%s\n" actm)))))) ))
>>
>>
>> This is for the same reason as above: the first invocation of `(car cmd)'
>> returns` (add-to-list 'load-path (marnap-sec-fpln-waypt
>> "NAPLN"))', which is a function call, not a function.
>>
>> Steve Berman
>
> Have put another question to not complicate this discussion.
> Would it make sense to execute the function calls with eval.
>
> Still that is also giving me problems with
>
> (invalid-function (add-to-list 'load-path (marnap-sec-fpln-waypt "NAPLN")))

This is probably because you have something like this:

(eval ((add-to-list 'load-path (marnap-sec-fpln-waypt "NAPLN")) ...))

That is, you're applying eval to a list, and eval treats a list like a
function call, so it expects the first element to be (or evaluate to) a
function, but `(add-to-list 'load-path (marnap-sec-fpln-waypt "NAPLN"))'
is, again, not a function but a function call.

Steve Berman