weird function?

[Moshe-A]

hey experts,

The following function returns a list of 4 angles and than causes AutoCAD to stuck and the cause of this is (angtos) can any one figure why?

(setq _degrees
   (lambda ()
     (mapcar
       (function
	 (lambda (ang)
	   (angtos ang 0 4)
	 )
       )
       (list (/ pi 4) (* (/ pi 2) 3) (* (/ pi 2) 5) (* (/ pi 2) 7))
     )
   )
 )

[paullimapa]

well this part of your code:

(mapcar
       (function
	 (lambda (ang)
	   (angtos ang 0 4)
	 )
       )
       (list (/ pi 4) (* (/ pi 2) 3) (* (/ pi 2) 5) (* (/ pi 2) 7))
)

Returns this:

("45.0000" "270.0000" "90.0000" "270.0000")

But when you do this you get a function:

(lambda ()
     (mapcar
       (function
	 (lambda (ang)
	   (angtos ang 0 4)
	 )
       )
       (list (/ pi 4) (* (/ pi 2) 3) (* (/ pi 2) 5) (* (/ pi 2) 7))
     )
)

AutoCAD returns:

#<SUBR @000001e69554f318 -lambda->

[ВeekeeCZ]

Exactly, what is the purpose of the outer lambda?

>> (setq _degrees (mapcar '(lambda (a) (angtos a 0 4)) (list (* pi 0.25) (* pi 1.5) (* pi 2.5) (* pi 3.5))))

>> ("45.0000" "270.0000" "90.0000" "270.0000") 

or 

>> ("45" "270" "90" "270")

...it depends on 'dimzin setting.

[Moshe-A]

@ВeekeeCZ ,

(setq _degrees (lambda (args)   ....    ))  ; create anonymous function

usage:

(_degrees) ; this returns the list as needed but than AutoCAD stuck

the result is the same even if changing it to regular function.

for test, if you replace (angtos) to (rtos) ... autocad does not stuck

(on my laptop on AutoCAD 2024 😀)

edit: sorry i had a mistake and fix it but this does not change the result, my AutoCAD get stuck

(defun degrees ()
  (mapcar
   (function
     (lambda (ang)
       (angtos ang 0 4)
     )
   )
   (list (/ pi 4) (* (/ pi 4) 3) (* (/ pi 4) 5) (* (/ pi 4) 7))
  )
 )

[ВeekeeCZ]

@Moshe-A 

sorry, I tried 2000 and 2025, and I don't see any issues. No lag, no stuck.

By the way, why do you prefer this construct? If I remember correctly, it was not recommended for some reason... What's the benefit of it over a classic named function?  

(defun _degrees () ...)

Edit: I see you used defun now... anyways, can't replicate the issue. Sorry.

[paullimapa]

no problems in my 2024.1.6 whether (_degrees) or (degrees)

[Moshe-A]

@ВeekeeCZ 

@paullimapa 

thanks for your help,

By the way, why do you prefer this construct? If I remember correctly, it was not recommended for some reason... What's the benefit of it over a classic named function?  

many years ago i saw here some one used it and like it. than i went back to the documentation and read this 

Use the lambda function when the overhead of defining a new function is not justified. It also makes your intention more apparent by laying out the function at the spot where it is to be used. 

and thought it is more efficient but now that you are asking i have second thoughts, maybe assigning it to a variable  actually defines a regular function?! 

Moshe

[ВeekeeCZ]

If you ask me, I would probably do something like this

(defun :angtos04 (rad) (angtos rad 0 4))

(setq angdec (mapcar (function :angtos04) (list (/ pi 4) (* (/ pi 4) 3) (* (/ pi 4) 5) (* (/ pi 4) 7))))
or just... 
(setq angdec (mapcar ':angtos04 (list (/ pi 4) (* (/ pi 4) 3) (* (/ pi 4) 5) (* (/ pi 4) 7))))

But I might not understand the context of your work. Also, I am not a theoretician, so it's just me.

Still, dunno why you got 'angtos stuck.

[dbroad]

To me, this would be preferrable and more readable to just assign the list to a variable: (setq degrees '("45.0000" "270.0000" "90.0000" "270.0000"))

What's the point of hiding logic inside a function?  What is weird is why those angles and why the different ways to calculate the 270 degree angles?

[Sea-Haven]

I have used this for use within lisps where need an angle as radians used multiple times in calcs. The function DTR RTD have been used for years so not sure why would need to do multi angles.

(setq pi45 (* pi 0.25) pi2 (/ pi 2.) pi135 (* pi 1.25) pi180 pi) 

Could do the same for degrees.

[Moshe-A]

@ВeekeeCZ 

@paullimapa 

update:

On my office machine with R2023 it works fine

on my laptop R2024 on new clean installation (only 10 day ago) it stuck

still if i replace (angtos) with (rtos) just for test it does work without...

any way guys thanks 😀

Moshe

[john.uhden]

@Moshe-A ,

I think the lambda function has to be preceded by either an apostrophe or the function function.

The 2nd example starts with (lambda ...) without any prefix so that's as far as it gets... returning the value of the lambda function itself and nothing else.

[john.uhden]

@Sea-Haven ,

I like your style.  Decades ago I adopted a similar convention...

(setq 1/4pi (* 0.25 pi)

          1/2pi (* 0.5 pi)

          3/4pi (* 0.75 pi)

          2pi  (* 2 pi)

    ;     etc.

)

At the time I thought that recalling a value by symbol name had to be faster than the calculation to create the value.

But since those days I think someone here (probably @Kent1Cooper) taught me that unless the value requires numerous steps to create, 'tis faster to create the value on the fly.  I don't think I ever tested.

Nevermind.  The tests I made on a tiny function revealed a tie.

[Moshe-A]

update:

the issue comedown to this:

at VLIDE console key in this expression

OK, return "90", AutoCAD window filp on and the VLIDE pops on the command line, AutoCAD enters to an unstable state, vlide is stuck and can be close only from Task Manager.

Could not be i am the only one having this?!  (AutoCAD 2024 Vanila)

i have checked Autodesk Access and there are no updates waiting to download.

[ВeekeeCZ]

@Moshe-A 

you're a programmer. you should know the drill... you need to break down the problem into pieces. 

(angtos (* pi 0,4) 0 4)

from what see...  

PI symbol, does it behave correctly, what about different calculations?

ANGTOS function, again, is definition ok? Can't that be redefined?

Units.. is there an issue with all units conversion, or just decimal? In ACAD, unit setting in a regular drawing, any sort of issues there?

Can't Windows be an issue? What about some country setting... how about Excel, all good there?

I can't really help you... you don't need to answer all the questions for me... I just wanted to point out possible causes to check, and maybe you'll come across something that will give you a clue and help you resolve the problem. If you've already done so, sorry, but you're not mentioning it.

Good luck!

[paullimapa]

Stopped using Vlide since Autodesk switched to VS Code. I’d recommend the switch 

[Moshe-A]

@ВeekeeCZ 

It only happen under vlide on R2024

On R2022 (on the same computer) it is working very well.

My machine: normal Laptop with windows 11

thank you

[Moshe-A]

@paullimapa 

Thanks

[calderg1000]

Regards @Moshe-A 

After the first lambda has been executed.
What sense would it make to use lambda without arguments and without an expression, on a list. Even more so without an apostrophe or preceded by "function"

In my opinion, this expression does not make sense. Its evaluation only results in the parameter falat message. But still my C3D will see. 2025, does not crash

(setq  _degrees
(lambda() (list "45.0000" "270.0000" "90.0000" "270.0000"))
 )

[Moshe-A]

@calderg1000 ,

---

@calderg1000 wrote:

Regards @Moshe-A 

After the first lambda has been executed.
What sense would it make to use lambda without arguments and without an expression, on a list. Even more so without an apostrophe or preceded by "function"

In my opinion, this expression does not make sense. Its evaluation only results in the parameter falat message. But still my C3D will see. 2025, does not crash

---

the answer to this is in my reply on message #7

thank you

Moshe