A
            keyword frame indicates a specific type of operation that occurs
            within the VLISP environment. The keyword indicates the type of
            operation. Keyword frames will appear in only two locations: at
            the very top of the stack, or at the very bottom of the stack.
         
         The following types
            of keyword frames will appear only at the bottom of a stack:
         
            
               
                  
                  
                  
                     Keyword
                           frames (bottom)
                         
                      | 
                  
                  
                     Frame type 
                      | 
                     Operation
                           that occurred
                         
                      | 
                  
                  
                     :ACAD-REQUEST 
                      | 
                     A call
                           to the function shown in the frame immediately above the :ACAD-REQUEST
                           keyword frame was invoked from the AutoCAD command prompt.
                         
                      | 
                  
                  
                     :DCL-ACTION 
                      | 
                     Execution
                           of a DCL tile or dialog action was requested from AutoCAD. The
                           keyword :DCL-ACTION is followed by two strings: the DCL dialog name
                           and the value of the $KEY variable in
                           the DCL action body. If a number appears, it is the value of the $REASON variable in the DCL action
                           body. The frame immediately above the keyword describes the function call
                           built from the action string. 
                         
                      | 
                  
                  
                     :INSPECT-EVAL 
                      | 
                     Evaluation
                           of an Inspect command.
                         
                      | 
                  
                  
                     :INSPECT-VERBOSE 
                      | 
                     Entrance
                           into a drawing Inspect hook function.
                         
                      | 
                  
                  
                     :TOP-COMMAND 
                      | 
                     The VLISP
                           IDE requested the action resulting in the first element placed within
                           the stack. This situation occurs, for example, when a function is
                           invoked directly from loading a selection or a file.
                         
                      | 
                  
                  
                     :USER-INPUT 
                      | 
                     The character
                           string shown in the frame was entered from the VLISP Console window.
                           The frame immediately above the keyword describes the expression
                           as it was translated from the user input. If the input string is
                           too long, right-click to open a shortcut menu, and choose Show Message
                           to view the entire text. You can also choose the Inspect command
                           to inspect the entered string.
                         
                      | 
                  
                  
                     :WATCH-EVAL 
                      | 
                     Evaluation
                           of a watch expression.
                         
                      | 
                  
               
            
          
         The following types of
            keyword frames may appear at the top of a stack:
         
            
               
                  
                  
                  
                     Keyword
                           frames (top)
                         
                      | 
                  
                  
                     Frame type 
                      | 
                     Operation
                           that occurred
                         
                      | 
                  
                  
                     :ACMD-CALLBACK 
                      | 
                     Registered AutoCAD command
                           call.
                         
                      | 
                  
                  
                     :AFTER-EXP  
                      | 
                     Indicates
                           that your program is interrupted in a debugging break mode, and
                           the Step Into or Step Over command just stepped out of an expression.
                         
                      | 
                  
                  
                     :ARQ-SUBR-CALLBACK 
                      | 
                     Indicates
                           a normal call from AutoCAD to a VLISP-defined function. 
                         
                      | 
                  
                  
                     :AXVLO-IO-CALLBACK :DWF :DWG 
                      | 
                     Saves or
                           restores a VL object in a DWG.
                         
                      | 
                  
                  
                     :BEFORE-EXP 
                      | 
                     Debugger
                           break upon entering the function. This message will appear whenever
                           you are stepping through using Step Into or Step Over, and the step
                           is entering an expression (as opposed to just leaving an expression,
                           which is indicated by the :AFTER-EXP keyword).
                         
                      | 
                  
                  
                     :BREAK-POINT 
                      | 
                     User-specified
                           breakpoint.
                         
                      | 
                  
                  
                     :ENTRY-NAMESPACE 
                      | 
                     A call
                           in the context of a separate-namespace VLX.
                         
                      | 
                  
                  
                     :ERROR-BREAK 
                      | 
                     General
                           runtime error. The Show Message shortcut menu selection allows you
                           to view more specific error messages.
                         
                      | 
                  
                  
                     :FUNCTION-ENTRY 
                      | 
                     Debugger
                           break upon entering the function. The stack element following this
                           message contains the call frame for the function in which the break
                           occurred.
                         
                      | 
                  
                  
                     :KBD-BREAK 
                      | 
                     The PAUSE
                           key was pressed, placing the program on hold.
                         
                      | 
                  
                  
                     :PROTECT-ASSIGN 
                      | 
                     Assignment
                           of a value to a protected symbol. From the right-click shortcut
                           menu, you can choose Show Message to view the variable name, the
                           current value, and the new value that was attempted to be assigned
                           to the variable. You can also choose the Inspect command to view
                           the list containing the symbol, and the new value indicated following
                           :PROTECT-ASSIGN.
                         
                      | 
                  
                  
                     :REACTOR-CALLBACK 
                      | 
                     Reactor
                           call.
                         
                      | 
                  
                  
                     :READ-ERROR 
                      | 
                     Error during
                           a read operation. The Show Message shortcut menu selection provides
                           additional information about the error.
                         
                      | 
                  
                  
                     :SYNTAX-ERROR 
                      | 
                     VLISP encountered incorrect
                           AutoLISP program syntax.
                         
                      |