The Visual LISP Developer's Bible - 2003 Edition - Autodesk

Within AutoCAD, you can remain type independent as you can with AutoLISP, but when it comes to interacting with other applications, such as Microsoft Excel, you will inevitably have to come to terms with data types and use them wisely. Being type independent is not a free lunch either. The price paid comes in the form of inefficient processing. ................
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