Expert: Scott Cook - 7/8/2008

Question
I have little experience with lisp, but i know some basic things.  My company has a lisp that will create layers depending on the type of drawing  being worked on I.E. mechanical, structural, piping, etc.  But we have special linetypes that are associated with some of the layers.  So at the begining of the lisp i use the command function to have cad load all the special linetypes that are needed.  The problem i am having is when 1 or some of the the linetypes are already loaded into the drawing the lisp errors out.  I know this because using the linetype command in cad it if a linetype you are trying to load is already in a drawing it alerts you of this and asks you if you would like to overwrite it. What needs to be done in the routine to accout for this?

Answer
There is a function called tblsearch you can use to determine if the linetype you are about to load is already loaded.
So your code would be something like:
(if (not (tblsearch "linetype" "mylinetype"))
 (command "linetype" ...)
)

Look up tblsearch in the online help in the lisp function reference for further explanation and to check my syntax. I'm just going from memory here.