With VLISP, you can select lines of code in the text editor window and run only the selected code, instead of the whole program.
To run selected lines of AutoLISP code in a Visual LISP editor window
(setq pt1(getpoint "\nEnter the start point for the line: ")
pt2(getpoint pt1 "\nEnter the end point for the line: "))
VLISP immediately runs the code and switches control to AutoCAD to prompt you for input.