sysvar changed reactor

[peter]

You cannot evaluate any string containing a LISP expression that
includes entity names or selection sets.

"(progn (setq ss (ssget))(if (> (sslength ss) 0)(setq ent (ssname ss 0))))"

Works OK and returns the LISP objectID of the first item of the selection set as a resultbuffer (list).

"(progn (setq XXXX (entlast))(foo XXXX))"

Would work OK.

I did find a couple of statements that are invalid though, so I guess I cannot evaluate ANY statement.

"(vlax-get-acad-object)"
"(vla-get-activedocument (vlax-get-acad-object))"

both would return nil because they do not have valid LISP objectID's or entity names.

Peter

[peter]

Tony,

I agree that .NET cannot create a entity name or LISP selectionset itself, but .NET Handles and LISP objectID's are the same.

I can convert .NET handles to entitynames easily. Similar for selection sets. See below.

If strObjectHandle is an .NET Object Handle

EvaluateLISP("(foo (objectIDToEName " & strObjectHandle & " ))")

Simlarly for Selection Sets.

No problemo.

Peter

(defun objectIDToObject (intObjectID)
 (vla-objectIDToObject 
  (vla-get-activedocument (vlax-get-acad-object))
  intObjectID
 )
)

(defun ObjectIDToEName (intObjectID)
 (vlax-vla-object->ename
  (vla-objectIDToObject 
   (vla-get-activedocument (vlax-get-acad-object))
   intObjectID
  )
 )
)
(vl-load-com)

Also

Without using acedInvoke(), you cannot call a LISP function from
.NET,

You can use the acedEvaluateLISP entry point also.

[peter]

This is not all of my code but an example of using the acedEvaluateLISP extry point for the others who are monitoring this thread. I am sure you know this code too.

I wanted to post this code first.

Imports Autodesk.AutoCAD.DatabaseServices
Imports Autodesk.AutoCAD.Runtime
Imports System.Runtime.InteropServices 'for DllImport()
Imports System.Security


Public Class vbvlClass
    ' Use P/Invoke for acedEvaluateLISP

    <System.Security.SuppressUnmanagedCodeSecurity(), DllImport("acad.exe", _
    CharSet:=CharSet.Unicode, CallingConvention:=CallingConvention.Cdecl, EntryPoint:="?acedEvaluateLisp@@YAHPB_WAAPAUresbuf@@@Z")> _
    Private Shared Function acedEvaluateLISP(ByVal strLISPExpression As String, ByRef intHandle As IntPtr) As Integer
    End Function
    '______________________________________________________________________________________________________________________
    '
    ' Overload of the EvaluateLISPExpression function to accept ResultBuffer as Argument
    '______________________________________________________________________________________________________________________

    <LispFunction("EvaluateLisp")> _
    Public Shared Function EvaluateLispExpression(ByVal rbfLISPExpression As ResultBuffer) As ResultBuffer
        Dim rbfReturn As New ResultBuffer
        Dim arrLispExpression As TypedValue() = rbfLISPExpression.AsArray
        Return EvaluateLispExpression(arrLispExpression(0).Value.ToString)
    End Function

    Public Shared Function EvaluateLispExpression(ByVal strLISPExpression As String) As ResultBuffer
        Dim rbfObject As IntPtr = IntPtr.Zero
        Dim rbfReturn As New ResultBuffer
        Try
            acedEvaluateLISP(strLISPExpression, rbfObject)
            If (rbfObject <> IntPtr.Zero) Then
                rbfReturn = CType(DisposableWrapper.Create(GetType(ResultBuffer), rbfObject, True), ResultBuffer)
                Return rbfReturn
            Else
                rbfReturn.Add(New TypedValue(&H138D, "Error"))
            End If
        Catch ex As System.Exception
            rbfReturn.Add(New TypedValue(&H138D, "Catch Error"))
            Return rbfReturn
        End Try
        Return Nothing
    End Function
End Class

[peter]

Tony,

Assuming that the .NET app could use a string builder to transform a .net selectionset into a string with all of the .net handles and spaces between them... this lisp function could convert it to a lisp selection set.

It really doesn't have to be this long but I allowed the list, a string with parenthesis on both ends or just a strings with the ObjectID's and spaces between them to be passed.

I had write it and test it first to respond.

I am sure I could condense it before I would be done with it.

No problemo.

Peter

(defun ListOfObjectIDsToSSet (lstOfObjectIDs / intCount ssReturn X)
 (if (= (type lstOfObjectIDs) 'STR)
  (if (= (substr lstOfObjectIDs 1 1) "(")
   (setq lstOfObjectIDs (eval (read (strcat "'" lstOfObjectIDs))))
   (setq lstOfObjectIDs (eval (read (strcat "(quote (" lstOfObjectIDs "))"))))
  )
 )
 (mapcar '(lambda (intObjectID)
           (if ssReturn
            (setq ssReturn (ssadd (objectIDToEname intObjectID) ssReturn))
            (setq ssReturn (ssadd (objectIDToEname intObjectID)))
           )
          )
          lstOfObjectIDs
 )
 ssReturn
)

[peter]

Tony,

I guess you probably figured out my trick you mentioned earlier.

I do not have .NET evaluate the LISP expression. the Invoke entry point only passes the lisp expression to a loaded lisp function as a string. Then the lisp routine evaluates it. That way I can have LISP revise the returning values to better interface with .net like converting a vla-object to an ename, a selection set to a list of objectID's etc...

I have not finished that part of the lisp code, but it really is not difficult to do.

(eval (read "what ever lisp expression you can think of"))

I am sure you can see the advantages of having LISP evaluate LISP. right?

You tell me what you think is the best way to have values returned from lisp that vb.net would digest the easiest.

Peter

[peter]

The fact is that there is little need to call LISP from .NET,

I guess we agee to disagree with this statement.

I have never promoted "not learning .net", I think all autocad customizers should learn it.

I only advocated that in order to help make a transition that lisp programmers need to:

First learn to program new lisp functions using .net (learning .net)

Second learn to program in .net while still being able to use all of their legacy code written in LISP.

Third be able to develop in either language based on the requirements of the application.

The right tool for the job.

Until you asked me I didn't plan on passing selection sets or entity names between the languages. You said it wasn't possible. I showed you it was. I can also create the result buffers in reverse and include all of the selection set information too. It is all easy to do.

Another easier way would to create selection set in .net then use the (ssget "p") in lisp and transfer all of the subentity information.

<<Moderator edited to conform to forum guidelines>>

I repsect your right to your opinion... You will not change my mind.

I would appreciate it if you would respect mine.

Peter