(/= var var) returns True

[Anonymous]

Why does this return True?

_$ (/= (GETVAR "INSBASE") (GETVAR "INSBASE"))
T

Say what now? TRYING to get my base point checked and set to (0,0,0) if it's not.

I.E.

(VL-LOAD-COM)
(DEFUN C:SOMFUNC( / ZEROLIST)
  (SETQ ZEROLIST (LIST 0.0 0.0 0.0))
  (COND
    ((/= (GETVAR "INSBASE") ZEROLIST)(SETVAR "INSBASE" ZEROLIST))
    (T NIL)
  (PRINC)
  )

[doaiena · Accepted solution]

Use equal to do this comparison.

(equal (GETVAR "INSBASE") (GETVAR "INSBASE"))
(not (equal (GETVAR "INSBASE") (GETVAR "INSBASE")))

[Anonymous]

That's twice I got caught with that "equal" operator in the past month or so.

Is this over complicated?

. . .
  (COND
    ((/= (GETVAR "CLAYER") 0)(SETVAR "CLAYER" "0"))
    ((NOT (EQUAL (GETVAR "INSBASE") ZEROLIST)) (SETVAR "INSBASE" (LIST 0 0 0)))
    (T NIL)
    )
. . .

I feel like there's a real simple way around that NOT operator. . . Either way, this works.

Thanks @doaiena

[Shneuph]

It seems like no matter what you want INBASE to be set to 0,0,0.  So, what if it's already 0,0,0 why check?  Just set it to 0,0,0 whether it is or not?

[doaiena]

@Shneuph is right in your case. You could just set the variables without checking their current values. Just these two lines:

(setvar "CLAYER" "0")
(setvar "INSBASE" '(0 0 0))

Also on another note, your cond statement won't work the way you intend to. cond evaluates from top to bottom, and once it gets a true statement in return, it executes that code and skips the rest. That means that the way you have written your code, if your current layer isn't "0" then it will be set to "0" and the cond statement will exit, without even checking for the insbase variable. 

If you want to check for multiple variables you should use an if progn statement, or some sort of loop over a list of variables.

And the last thing:

...
(COND
    ((/= (GETVAR "CLAYER") 0)(SETVAR "CLAYER" "0"))
...

This statement will always return true, because (getvar "CLAYER") returns a string, and you are comparing it to an integer. That means that in your code the current layer will always be set to "0" and it will never check for the insbase variable.

[Kent1Cooper]

---

@Anonymous wrote:

. . .
  (COND
    ((/= (GETVAR "CLAYER") "0")(SETVAR "CLAYER" "0"))
    ((NOT (EQUAL (GETVAR "INSBASE") ZEROLIST)) (SETVAR "INSBASE" (LIST 0 0 0)))
    (T NIL)
    )
. . .

....

---

I don't think (cond) is the right thing to use here.  It makes one property dependent on another un-related one.  If the current Layer isn't 0, it will see that condition as True, and will set it to 0, and then because it's found a non-nil condition by then, not go on to check the INSBASE value at all.

Also, that  (T nil)  line is kind of pointless -- just omit it, because (cond) will return nil without it, if all the conditions tested for did so.

But I agree that there's really no need to test for these things, if you want them to have a certain value in any case.  Just set them to that, whether they are already or not.  All of your code window could be replaced by just:

(SETVAR 'CLAYER "0")

(SETVAR 'INSBASE '(0 0 0))

[Anonymous]

That's much easier. 

Thanks for all the input.