change draw order if layer exists

Hi everyone

I am trying to write short lisp to check if layer (specified in a lisp) exists and if so change it's draw order (send it to back or front). I have combined my 2 other lisps which both work just fine and found out that now it doesn't work: "error: bad function: "

The code goes like this:

(defun C:cdo( );  Correct Draw Order
(progn
(if (tblsearch "LAYER" "l1");test if layer exists
(
(setq la1 (ssget "X" '((8 . "l1"))))
(command "draworder" la1 "" "F")
);else
(command "");do this
);end if
(princ)
)
)

I didn't put anything after "else", however the error appears even when the layer exists. It must be something really simple but I got confused and can't find the error by myself. Can someone point it out for me, please?

(defun c:SendLayerToBack (/ ss)
 (if (setq ss (ssget "_x" '((8 . "L1"))))
   (progn
     (sssetfirst nil ss)
     (ai_draworder "_b")
   )
   (prompt "\n** Layer not found ** ")
 )
 (princ)
)

(defun c:BringLayerToFront (/ ss)
 (if (setq ss (ssget "_x" '((8 . "L1"))))
   (progn
     (sssetfirst nil ss)
     (ai_draworder "_f")
   )
   (prompt "\n** Layer not found ** ")
 )
 (princ)
)

Thank you for quick response. Your code works perfect:) I was just wondering what am I doing wrong? Can you tell me where this error may come from in my code? It is just for my understanding of the lisp.

Thanks again

Thank you for quick response. Your code works perfect:) I was just wondering what am I doing wrong? Can you tell me where this error may come from in my code? It is just for my understanding of the lisp.

You're welcome, bohoon; I'm happy to help.

By simply checking for a valid selection set, you both verify that the layer exists, and that there are objects on said layer - note that this does not check for locked layers, as is just an example. Once that returns non-Nil, the previously made selection set is selected on screen, as the draw order sub-function (ai_draworder) requires an implicit selection be made first, and then we call the sub-function supplying the necessary 'back' or 'front' parameters to complete the Command.

Hope that make (more?) sense now.

Cheers

OK, So your function ai_draworder requires selection to be made first. However I thought I did the same in this 2 lines:

(setq la1 (ssget "X" '((8 . "l1"))))
(command "draworder" la1 "" "F")

made a selection la1 and then use it in regular draworder command

It did work before I added an "if" function :

(if (tblsearch "LAYER" "l1");test if layer exists

Does it mean that somehow inside "if" it switches the order of my commands?

OK, So your function ai_draworder requires selection to be made first.

It's not my sub-function; it's AutoCAD's and is defined within Acad20##Doc.lsp

However I thought I did the same in this 2 lines:

 

(setq la1 (ssget "X" '((8 . "l1"))))
(command "draworder" la1 "" "F")

 

made a selection la1 and then use it in regular draworder command

It did work before I added an "if" function :

 

(if (tblsearch "LAYER" "l1");test if layer exists

 

Does it mean that somehow inside "if" it switches the order of my commands?

No, your call to TBLSEARCH returns non-Nil, so your IF statement's test expression is fine - it is unnecessary given the fact that you want to manipulate entities found on said layer, just call SSGET instead which tests for a valid selection set of entities on said layer (which implicitly exists, if entities are assigned that layer).

In a quick test, these also work fine:

(defun c:SendLayerToBack2 (/ ss)
 (if (setq ss (ssget "_x" '((8 . "L1"))))
   (command "._draworder" ss "" "_b")
   (prompt "\n** Layer not found ** ")
 )
 (princ)
)

(defun c:BringLayerToFront2 (/ ss)
 (if (setq ss (ssget "_x" '((8 . "L1"))))
   (command "._draworder" ss "" "_f")
   (prompt "\n** Layer not found ** ")
 )
 (princ)
)

... The main difference being that my functions supply the "_b" and "_f" localized options, and your original code above does not. In one test adding this localized option does 'fix' your code.

HTH

Thanks again. I appreciate your help.

Thanks again. I appreciate your help.

You're welcome.