#Autocad lisp routines for surveyors how to#
#Autocad lisp routines for surveyors code#
#Autocad lisp routines for surveyors series#

There’s some 35 years of experience and code out there, and someone is always willing to help. Whether via AutoCAD’s own Help system or various sites and forums on the internet and Autodesk Knowledge Network, don’t hesitate to reach out.

#Autocad lisp routines for surveyors how to#

What else should a beginner know? You should know how to load external AutoLISP files (LOAD, APPLOAD, Drag and Drop), and how to identify the Function name needed to run them at the Command Line.įinally, you should know how to get help.

Basic list manipulation functions: LIST, CONS, CAR, CDR, NTH.

AutoLISP specific “GET…” functions: GETSTRING, GETREAL, etc.

AutoLISP specific functions: COMMAND, GETVAR, SETVAR.

(functionName argument1 (functionName argument1 argument2) argument3 …)Ī beginner should be aware of internal AutoLISP functions, especially DEFUN and SETQ. You should be aware that expressions can be nested, and that you evaluate them from the inside out. Without going into a dissertation on “Functional” languages, just remember that while we may tend to use AutoLISP in a procedural manner within a CAD program, it is much more powerful than that.

In the simplest terms, those languages execute a line of code, move on to the next, and so forth until complete. That’s an important point, as it sets AutoLISP apart from other languages that are considered “Procedural” languages. Note: It’s important to note here that every Expression returns a value. Next, is that the function is always the first item (or ATOM) in a list. The basic rules of AutoLISP are that everything is contained within a set of parentheses. Syntax can be defined as the rules that any kind of language uses. Those are the ATOMS that follow the Function call in the expression. The functions that AutoLISP uses are called…FUNCTIONS-that’s easy! And FUNCTIONS sometimes require ARGUMENTS. In fact, the interpreter is built into AutoCAD, so you can run expressions right from the Command Line.Īs for basic Terminology and Syntax, you should know that items within a list are ATOMS. There’s no need to compile your code either. Note: One of the reasons AutoLISP is so easy for non-programmers (people like us) is that you don’t have to manage data types and memory allocation like other languages. Others include STRINGS, REAL numbers, and INTEGERS. AutoLISP considers a LIST or a CONS as a data type. Of course, there are various data types you’ll need to be familiar with. You’ll need to know about them, whether they’re defined as a LIST, a CONS, a DOTTED PAIR, or an S-EXPRESSION (or just EXPRESSION for short). Everything in the language is a list in some form. I think it’s important for any AutoLISP user to know what it is.

Right now, we’ll start at the very beginning.

#Autocad lisp routines for surveyors series#

This three-part series will help you become aware of the kinds of things you can do with AutoLISP at three levels of expertise: Beginner, Intermediate, and Advanced. It really doesn’t have to be, and even with just minimal knowledge, you can still accomplish a lot. You may not consider yourself a programmer, or it might just be intimidating. I just love AutoLISP, and I consider it my “home” language.īut I also understand that my love of the language isn’t universal.

Architecture, Engineering and Construction.

Architecture, Engineering & Construction.