From: [email protected] (Reini Urban)
Newsgroups: comp.cad.autocad,alt.cad.autocad,alt.answers,comp.answers,news.answers
Subject: comp.cad.autocad AutoLISP FAQ (part 1/2) - general
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Keywords: FAQ, AutoLISP, AutoCAD
Summary: AutoLISP is a scripting language for AutoCAD, a wellknown CAD
 package. This AutoLISP FAQ is posted to comp.cad.autocad, alt.cad.autocad
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Posted-By: auto-faq 3.2.1.5
Archive-name: CAD/autolisp-faq/part1
URL: http://xarch.tu-graz.ac.at/autocad/news/faq/autolisp.html
Version: 2.28
Last-modified: 2002-06-25
Posted-By: Reini Urban <[email protected]>
Posting-Frequency: monthly
Copyright: see Appendix [A]

       Welcome to the comp.cad.autocad AutoLISP FAQ
         by Reini Urban <[email protected]>

Autolisp is a scripting language for AutoCAD, a well known CAD package.
This AutoLISP FAQ is posted to comp.cad.autocad, alt.cad.autocad and
the *.answers groups monthly. Some AutoCAD FAQ's are at
http://www.autodesk.com/support/autocad/ but not posted to
comp.cad.autocad. The contents and the samples apply to all
releases of AutoLISP since Release 10, including Visual Lisp, Vital Lisp
and ACOMP. There's no special AutoLISP newsgroup.
Best are comp.cad.autocad and autodesk.autocad.customization,
but please don't bother comp.lang.lisp.
Source code of all functions in this FAQ is in FAQ-CODE.LSP
(for location see [A.1]), there's also a Winhelp file.
Thanks to all who have contributed. Corrections and contributions
always welcome.
Please see http://xarch.tu-graz.ac.at/acadwiki/RulesToLiveBy

This is part 1/2 of the AutoLISP FAQ v2.28, which consists of:

   AutoLISP FAQ (part 1/2) - General
   AutoLISP FAQ (part 2/2) - Samples, code

| changes, + new in items from this version to the last posted version,
intermediate personal comments and uncertainties in <..>

 -----------------
 Table of Contents
 -----------------
 part 1:   General
    [0] The Future of AutoLISP? Should I learn it or VB instead?
      [0.1] What changed with AutoCAD 2000?
      [0.2] We cannot create ARX anymore?
    [1] Where can I find AutoLISP routines on the Internet?
      [1.1] Are the comp.cad.autocad articles stored somewhere?
      [1.2] Autodesk's SDK
    [2] What are the best books to learn AutoLISP?
      [2.1] Online AutoLISP documents, Winhelp [deleted]
      [2.2] AutoLISP Coding Style
    [3] How do I debug AutoLISP programs?
       [3.1] Native AutoLISP debuggers
       [3.2] Modular style, TRACE
       [3.3] BREAK function, debug-print
    [4] How can I protect my AutoLISP programs? Security
      [4.1] Kelvinate
      [4.2] Protect
      [4.3] Kelvinate and Protect
      [4.4] Convert
      [4.5] ACOMP
      [4.7] Lisp2C
      [4.6] Vital LISP Professional
      [4.8] Visual Lisp by Autodesk
    [5] AutoLISP compilers
      [5.1] ACOMP
      [5.2] Vital LISP Professional
      [5.3] Visual Lisp by Autodesk
      [5.4] Better ones: Common Lisp and Scheme
    [6] AutoLISP editors and other tools
      [6.1] AutoLISP editors
      [6.2] Analyzers, Packager and Parenthesis checkers
      [6.3] Pretty Printers
    [7] AutoLISP problems and bugs
    [8] Sorting with AutoLISP
    [9] Recursion
    [10] Iteration with MAPCAR,...
+    [11] S::STARTUP, My LISPs aren't loading at startup anymore
    [12] How to AUTOLOAD my programs?
    [13] How can I pass a variable number of
         arguments to a LISP function?
    [14] How can I avoid stack overflows?
    [15] (command "ROTATE3D") does not work! Why?
    [16] Lisp programs operating over multiple drawings
    [17] How to export Visual Lisp functions to AutoLISP/AutoCAD?
    --
    [A] Disclaimer, Notes from the authors
      [A.1] FAQ Locations

 part 2:   Samples, code
    [20] General Helper functions
      [20.1] List manipulation
      [20.2] String manipulation
      [20.3] symbol->string
      [20.4] AutoCAD entity access
    [21] Sample Lisp programs
      [21.1] Globally change text, polylines, layer utils, date stamp
      [21.2] Plot dialog from within LISP. Using DDE or ActiveX
      [21.3] (entmod),(entmake) Layers, without (command "_LAYER"...)
      [21.4] How to select multiple files in LISP? (as in FILES-Unlock)
      [21.5] Replace multiple blocks
      [21.6] (vports), VIEWPORT entity, pixel conversion
      [21.7] Select all visible objects: zoom coordinates
      [21.8] How to write XYZ data of selected objects to a file?
    [22] Block Attributes
      [22.1] How to access block attributes?
      [22.2] How to MODIFY block attributes? DATESTAMP.LSP
      [22.3] How to UPDATE block attributes?
      [22.4] How to ENTMAKE a Block Complex Entity in AutoLISP
    [23] Polylines
      [23.1] How to access polyline VERTICES?
      [23.2] How to JOIN multiple lines to polylines?
      [23.3] Change WIDTH of multiple polylines
      [23.4] Create a polyline or spline: with (ENTMAKE) or (COMMAND)
      [23.5] How to calculate the LENGTH of polylines?
      [23.6] How to revert the polyline direction?
      [23.7] How to get the CENTER of a polyline?
    [24] Circle/Arc Geometry:  BULGE conversion, some trigonometry
    [25] DCL: listboxes with tabs or monotext font
    [26] EED Extended Entity Data: Get and Store
      [26.1] Select objects on their EED with (ssget "X")
      [26.2] Get EED from an object
    [27] How to break a command in LISP?
      [27.1] How to do an unlimited number user prompts?
    [28] How to decode ACIS internal geometry with LISP
    --
    [A] Disclaimer, Notes from the author
+      [A.1] FAQ Locations
    [B] Acknowledgements
    [C] Recent Changes

----------------------------------------------------------------------
Subject: [0] The Future of AutoLISP? Should I learn it or VB instead?

 AutoLISP will be definitely supported in future releases.
 VB was introduced to simplify Office Automation: ACAD <-> Excel/Access
 Both languages have advantages and disadvantages. You should take a look
 at both. VB seems to be more graphical and AutoLISP more logical. The
 object concept of VBA seems to be easier to learn, but you cannot run
 commands like in AutoLISP. The new VBA (>= R14.01) is extremely fast.
 See also [5.2]
 The future of AutoLISP already is Visual Lisp. For VLISP see [5.3]
 URL's: http://www.autodesk.com/vlisp,
 http://www.autodesk.com/develop/devres/visual/faq.htm, also [0.1] below.

 [0.1] What changed with AutoCAD 2000?

 The name :) No, there's much more, but you may call it Release 2000, R15
 (though 15 is the version number and not the release number),  A2000 or
 abbrevated A2K.
 The new Visual Lisp kernel (formerly "Vital Lisp") replaced the old
 xlisp-based AutoLISP kernel.

 What problems should you expect with Visual Lisp in R2000? (only the bad
 news). At http://xarch.tu-graz.ac.at/autocad/docs/r2000-news.txt
 I compiled a white paper. The major points are:
 Stricter error checking on loading, ACAD.LSP vs ACADDOC.LSP,
 You cannot/need not compile to ARX anymore, Incompatibilities
 AutoLISP - Visual LISP: Lisp functions are atoms no lists anymore,
 Protected symbols,
 Better exception handling, Pathname of the loaded VLX?,
 vl-export-symbol -> vl-doc-set, long acad symbol table names: EXTNAMES
 ActiveX automation, Variants and SAFEARRAYs, FAS4 cannot be loaded on R14.

 [0.2] Why cannot I create ARX anymore?

 With AutoCAD 2000 you cannot do that anymore as with ViLL or VLISP 4.
 Instead you compile to VLX (Visual Lisp Extension), which has basically
 the same functionality as the old Visual Lisp/Vital Lisp ARX, with the
 following differences:

* You'll have to (load) the app. Before you had to (arxload) it.
- Pro: Initialization is easier. The VLX doesn't abort completely on any
 error while loading. Before the whole ARX crashed with mysterious
 errors.
- Pro: VLX are much smaller because they don't carry the whole Lisp
 environment, the VLRTS, along. Instead there's only one environment,
 VL.ARX, distributed with acad itself. So you can ship much smaller
 applications.
- Contra: With loaded VLX there's no easy way to get the pathname of the
 app. Before it was possible with (arx) or (vl-exe-filename)

* VLX has the option of seperate or common namespaces. With seperate
 ARX you had only the option of seperate namespaces (in fact completely
 seperate lisp environments).
- Pro: This means that you can now choose the fastest and most secure
 compilation mode (LINK, DROP) and still keep common namespaces. (most of
 my apps benefit from this. I seperated my apps into one main module and
 several smaller ones)
- Pro: ARX is only compatible per release, thus completely incompatible!
 VLX is new and therefore compatible only to newer releases (R16,...) but
 as lisp application it is by far more compatible than a ARX app.

* Loaded ARX apps with (arx) return the pathname, loaded VLX apps with
 (vl-list-loaded-vlx) only a symbol, no path. This is a design flaw.

 You don't need ARX modules anymore. This is a feature, no bug.

------------------------------

Subject: [1] Where can I find AutoLISP routines on the Internet?

 The big AutoCAD tools sites with LISPs are:

 "AutoCAD Plugin Store" by beyond.com
    http://www.cadplugins.com/
    This is the by AutoDESK "officially recommended" tools site.
 "CADalog" - The AutoCAD Shareware Clearinghouse (Mike Clark)
   http://www.cadalog.com/
 "The CAD Depot", formerly known as "cadsyst" or "Rolling Stock Software",
   (David Whynot) recently bought by TenLinks.com
   http://www.caddepot.com/

 They are specialized in AutoCAD related software and have a very
 good AutoLISP collection. Other professional AutoLISP shareware
 sites post their URL's to the newsgroup too.

 Other relevant sites are:
 TenLinks (www.tenlinks.com) and the UpFront (www.upfrontezine.com) ezine
 are the best CAD news services. Autodesk also started their portal site
 "Point A" at http://www.autodesk.com/pointa

 Some more sites with AutoLISP collections are:

 The CAD Users Webring
   http://nav.webring.org/hub?ring=caduser&list
 xarch AutoCAD Info & Tools (Reini Urban)
   http://xarch.tu-graz.ac.at/autocad/    (with search)
 CADalyst magazine code (compiled by "Hot Tip Harry" Art Liddle)
   http://www.cadonline.com/code/   (with search)
 Owen Wengerd
   http://www.manusoft.com/
 Terry Dotson
   http://www.dotsoft.com/
+ AcadX
+   http://www.acadx.com/
+ Paul Turvill
+   http://www.turvill.com/t2/
 Vladimir Nesterovsky
|   http://vnestr.tripod.com/
 Theo L.A. Groenenberg
   http://members.xoom.com/acadvice/autolisp.htm
 The CADshack (Jeff Foster)
|   http://www.cadshack.com/
 Lisp Factory (Jay Garnett)
   http://www.enteract.com/~jgarnett/
 Rakesh Rao - AutoCAD Tech Center
   http://www.4d-technologies.com/techcenter

 Older or broken links:
 AutoCAD Tech Journal code (Peter Sheerin)
   http://www.atj.com/ (old)
 CADENCE magazine code (Peter Sheerin)
|   http://www.cadence-mag.com/ (fixed)
 UCCB AutoCAD and AutoLISP page (Paul Standing)
   http://ucad1.uccb.ns.ca/acad/cad.htm (broken)
 McNeel's old lisp archive
|   ftp://ftp.mcneel.com/pub/lisp/ (fixed)
 Dr.Lisp Utilities (Alexander Medwedew)
   http://idt.net/~compvent/ (fixed)
 SimTel - Coast To Coast - Archive (fixed, really very old stuff)
|   http://www.simtel.net/pub/msdos/autocad.html

| At http://support.autodesk.com/ (moved) were documents from the
 Autodesk Product Support answering technical questions. (Their FAQ's)
+ The ASA (Support Assistance, some kind of FAQ) was once at
+ http://www.autodesk.com/support/autocad/asa2000.htm, an improved but
+ slow tool is now at http://support.autodesk.com/KnowledgeBase.asp.

[1.1] Are the comp.cad.autocad articles stored somewhere?

 There is no comp.cad.autocad archive or such a thing, but there
 are some search machines which store news articles. In
 particular:

| * http://groups.google.com/       - The biggest news archive
|     formerly known as http://deja.com/usenet
 * http://www.altavista.com/
     http://www.altavista.com/cgi-bin/query?pg=aq&what=news
 * http://www.excite.com/
     http://www.excite.com/search.gw?collection=news
 * Phoaks - People Helping One Another Know Stuff - Automatic Links Extractor
     http://www.phoaks.com/phoaks2/newsgroups/comp/cad/autocad/index.html

 The Autodesk discussion forums have also a search feature at
| http://discussion.autodesk.com

 Some specific older news postings are also stored at
 http://xarch.tu-graz.ac.at/autocad/news/contents.html

[1.2] Autodesk's SDK

 Up to Release 12 a Software Development Kit was available directly
 at Autodesk. The SDK1-2 was shipped with the international R12 for
 free. It included a lot of ADS and AutoLISP source code and libraries.

 From R13 on Autodesk provides a special developers network, comparable
 to Microsoft's, the ADN. The CD's are comparable to the old SDK but
 are more targeted to ObjectARX developers.
 Contact your nearest Autodesk headquarter for becoming a member.

 Some LISPs are at http://xarch.tu-graz.ac.at/autocad/code/adesk/SDK2

 In the US, ADN membership costs $600.00 per year.  The CDs don't include
 any SDK per se, but most of the stuff in the original SDKs is included
 in one form or another. (Owen)

------------------------------

Subject: [2] What are the best books to learn AutoLISP?

 AutoLISP to Visual LISP
   Kevin Standiford, Autodesk Press, ISBN 0-7668-1517
 AutoLISP: Programming for Productivity,
   William Kramer, Autodesk Press, ISBN 0-8273-5832-6
 Essential AutoLISP,
   Roy Harkow, Springer-Verlag, ISBN 0-387-94571-7
 AutoLISP in Plain English, A Practical Guide for Non-Programmers,
   George O. Head, Ventana Press, ISBN 1-566-04140-6
 AutoLISP Reference Manual
   Autodesk Press.
   Up to R12 there was a separate AutoLISP Reference book. Then AutoLISP
   became a part of the Customization Guide for R13. From R14 on this
   guide is compiled as Winhelp.
 Maximizing AutoLISP
   Rusty Gesner, Tony and Mark Middlebrook, Tony Tanzillo.
   A new Maximizing AutoLISP R13/R14 will be published hopefully
   sooner or later. But the R12 book is still worth buying, though it's
   difficult to find. More at http://www.group-a.com/~rusty

 There is a lot more AutoLISP books around.
 Recommended general LISP books (not AutoLISP!) are:
 ANSI Common Lisp, (Common Lisp primer)
   Paul Graham, Prentice Hall, ISBN 0-13-370875-6
 Structure and Interpretation of Computer Programs, (high-level Scheme)
   H.Abelson, GJ. Sussman, J. Sussman, MIT Press, ISBN 0-262-01153-0
   "This undoubtedly one of the best general computer books ever written."
 LISP, 3rd Edition,
   Patrick Henry Winston and Berthold Klaus Paul Horn,
   Addison-Wesley Publishing Company, ISBN 0-201-08319-1
 Looking at LISP,
   Tony Hasemer, Addison-Wesley Publishing Company, ISBN 0-201-12080-1


[2.1] Online AutoLISP documents, Winhelp [deleted]

[2.2] AutoLISP Coding Style

 Most of the samples being published by magazines or at various
 websites are written badly making the AutoLISP learning process even
 harder for newbies. LISP is hard to read anyway because of it's
 briefness and countless parentheses. Everybody is enforced to
 write clear, readable code. Autodesk's samples are quite well written
 but sometimes overdone. :)

 Automatic pretty printers, or so called beautifiers (see
 [6.3]) automatically format the code according to some kind of standard.

 On the R12 CD-ROM in the SDK2 ACG.DOC or at
 http://xarch.tu-graz.ac.at/autocad/docs/acg.txt is an excellent
 Autodesk documentation about coding, commenting and intentation standards
 to keep lisp code readable.

 The most important points are:
 * Comment your code using ";;;" at row 1, ";;" inside the code
   (indented) and ";" for trailing comments (at row 39)
 * Follow the indenting standards as given by the pretty printers
   to be able to write better structured code, which is more readable.
     esp. for SETQ, DEFUN, IF, COND, PROGN
 * Try to avoid global variables. If you use them (for efficiency), to
   clarify, place asterics around them in uppercase, i.e: *GLOBAL*
 * Don't forget to localize your variables (behind "/" in the DEFUN
   parameter list). Only for debugging purposes you may want to
   undefine them temporarly.
 * Name protection: Since AutoLISP provides no protected name space,
   it's easy to overwrite even system functions. Use unique
   short prefixes at least when you publish or give away your code.
   I use UR- for functions and UR: for variables. The ADGE and Autodesk
   forces even 4 letter prefixes. Then your names are safe
   from being overwritten by other kamikaze functions.
 * Always use the leading underscore with any string (commands and
   options) given to COMMAND and OSNAP. There are even enough
   commercial programs which do not work on international versions.
   (command "_PEDIT" ss "_J") is better than (command "PEDIT" ss "J")
 * Don't do too much SETQ's: LISP was originally a functional language,
   without any variables. There are enough constructs which work
   efficiently with lists without the need of storing values
   intermediatly in symbols. (see code samples [22]...)
   But for readability and debugging purposes you should always set
   symbols.
 * An old LISP rule is: Any good function is not longer than 6 lines :)
   (LISP is the second oldest computer language, invented by John
   McCarthy at the MIT in 1958)
 * Prefer CONS over APPEND: three CONS and one REVERSE is better than
   one APPEND. For tricks with APPEND (omitting NIL) see esp. Serge's
   samples: i.e. REMOVE at [11] or the style comparison at [23.1])
 * Try to use English symbols and comments
 * Don't use T, MIN, MAX or LAST as symbols! These are system functions!

------------------------------

Subject: [3] How do I debug AutoLISP programs?

[3.1] There are some native AutoLISP debuggers:

 * Visual Lisp by Autodesk and Vital Lisp Professional support
   it in the IDE (the best),
 * ACOMP for R10 had one, (free)
    you can still use it with R12 DOS, but then you've got only the R10
    LISP functions, i.e. no WCMATCH function,
 * Ld, AutoLISP Debugger for R14, R13c4 and R12/DOS from CZ,
   (free) at http://www.cadstudio.cz/ftp.htm

 See "[5] AutoLISP compilers"

[3.2] Modular style, TRACE

 The best support you can have for debugging is write your
 code in a well designed, modular style, pulling out distinct
 tasks into separate functions and then liberally using
 nested function calls. This will allow you to use the
 TRACE function as needed to locate any errors.

[3.3] You may include BREAK functions and debug-print into your source
 code.

 Examples:

 ;;; Debugging functions
 (defun break (s)
   (if *BREAK*
     (progn
       (princ "BREAK>> (stop with <Enter>)\nBREAK>> ")(princ s)
       (while (/= (setq s (getstring "\nBREAK>> ")) "")
         (print (eval (read s)))))))
 (defun dbg-print (s)  ;accepts atoms and lists
   (if *DEBUG*
     (if (listp s)
       (MAPCAR 'print s)
       (print s))))
 (defun C:DEBUG () (setq *DEBUG* (not *DEBUG*)))  ;switch it on and off
 (defun C:BREAK () (setq *BREAK* (not *BREAK*)))
 (defun CONT () (setq *BREAK* nil))    ;cont. without any interruption

 For a usage example see:
   http://xarch.tu-graz.ac.at/autocad/news/break_ex.lsp

------------------------------

Subject: [4] How can I protect my AutoLISP programs?

 "You really have to protect it? If you just want to share routines
 with friends, why not give them the code? Working with others
 can be a great way to get new ideas and lead to a better
 application. Some of the best utilities were improved by my friends
 or I have improved some of my friends utilities." (Dennis)

[4.1] Kelvinate
   with KELV.EXE (on the R12 CD-ROM or at the AutoLISP sites "[1]").
   Free. De-Kelvinate LISP's with any pretty printer, see [6.3].
   Symbol names (functions and variables) will stay garbled and comments
   are lost.
[4.2] Protect
   with PROTECT.EXE (on the R12 CD-ROM or at the AutoLISP sites "[1]")
   Note that unprotectors exist. Free.
[4.3] Kelvinate and Protect
   First kelvinate, to make it unreadable, then protect. Free.
[4.4] Convert
   Shareware LISP En-/Decryptor by Maciej Lukasiewicz, Sweden.
   With Convert encrypted "Protected Lisps" cannot be decrypted by other
   programs, but by Convert it can.
[4.5] ACOMP
   AutoLISP compiler ACOMP.EXE, on the R12 international release or
   at the AutoLISP sites. Free. More docs about ACOMP are at
   http://xarch.tu-graz.ac.at/autocad/bi4/  See also [5.1]
[4.6] Vital LISP Professional
   Formerly at http://www.basissoftware.com/vill.htm [broken]
   Say "ViLL". Outdated. See also [5.2]
[4.7] Lisp2C
   LISP to C converter, for R12/R13/R14 Dos/Win (Watcom, Metaware,
   MSVC Libs). You need to own such a C/C++ compiler. Quite expensive.
   http://www.basic.si
[4.8] Visual Lisp by Autodesk
  say "VLISP". see [5.3]


 FAS Security:
   There was recently a lengthy discussion about FAS security at both
   newsgroups. Apparently FAS can be decompiled to readable source code,
   but this tool is not available on the net yet. Rumors say that MNC
   files can also be decompiled for years now but this doesn't exist the
   net either.
   Linked and dropped FAS/VLX (compiled with Optimized/Internal) is
   similar to Kelvination.
   Symbol names, strings and numbers are more insecure than algorithms.
 Summary:
   Serious encryption is only done with Vital LISP and its successors.
   Kelvinating makes LISP files unreadable and load faster.
   Protected lisp files can be easily decrypted. With
   Convert -e$GUARD encrypted LISPs can be unprotected only with Convert.

------------------------------

Subject: [5] AutoLISP compilers

 There are three AutoLISP compilers, better ones could maybe used in the
 future. Some Lisp and Scheme platforms already do or will support ActiveX
 or just a simple FFI.

[5.1] ACOMP
   ACOMP was supported up to R12 for the international releases only.
   It is free, and doesn't work with R13 nor with domestic R12/Win.
   It produces .BI4 files and needs special ACADL.EXP supplied as
   ACADLC.EXP     See http://xarch.tu-graz.ac.at/autocad/bi4/
[5.2] Vital LISP Professional
   by Basis Software Inc. USA.
   Basis doesn't continue developing Vital Lisp anymore.
   License-free runtime modules for R12/R13/R14 DOS/Windows/NT
     See http://www.basissoftware.com/vill.htm
   Some dealers still have it on stock. The latest version was 3.2. The
   R14 version (ViLL 3.x) includes ActiveX (like VB) and reactor
   support. See also [6.1] and [4.6]
[5.3] Visual Lisp by Autodesk
   VLISP 4 (for R14), the successor of Vital Lisp, is basically the same
   as ViLL 3.2, only the GUI, some function names and the docs changed:
     vill- => vlisp-, the vlx- => vl- prefixes.
     Some vlax- funcs have more hyphens.
   With AutoCAD 2000 VLISP replaced the old AutoLISP engine. See [0.1]
   VLX files are packaged FAS files with optional DCL resources, used
   by R14/R15.
   AutoCAD 2000 FAS/VLX are incompatible with previous releases
   (FAS2 -> FAS4) because of added language features (seperate namespaces)
[5.4] Better ones: Common Lisp and Scheme
   Native ARX exists for Corman Common Lisp (a simple console),
   COM support for Allegro Common Lisp 5, Lisp Works for Windows and in
   the future for GambitC.
   Via a FFI ("Foreign Function Interface") almost every lisp or scheme
   can communicate with AutoCAD.
   See http://xarch.tu-graz.ac.at/autocad/lisp/ffis.html
   Little work is done with Corman Lisp and ACL5, one commercial product
   uses ACL5 ("Design++" by Design Power http://www.dp.com/)
   See http://xarch.tu-graz.ac.at/autocad/bi4/ for more.

 Summary:
   AutoLISP compilers are bytecode compilers needing a runtime system.
   AutoCAD 2000 uses VLISP now, so the runtime system is included.
   You cannot create standalone programs, though ViLL/Vlisp (<=R14)
   creates a stand-alone ARX. The symbols are encrypted.

------------------------------

Subject: [6] AutoLISP editors and other tools

[6.1] AutoLISP editors
 Visual Lisp by Autodesk
   see [5.3]. The best and most recommended tool. With AutoCAD 2000 it
   is included for free.
 Emacs for NT
   Huge editor and quite hard to learn but it's written and
   customizable in LISP. Free, for all platforms. Comes in two flavors,
   www.xemacs.org or the GNU emacs for NT.
   Check out http://xarch.tu-graz.ac.at/autocad/lsp_tools/ntemacs.html
 Vital LISP
   outdated by Visual Lisp. Not available anymore
 LispLink 2000
   Commercial AutoLISP Editor with Syntax Highlight, Parenthesis
   Checking, Project Manager, Dialog Preview, and Support for Visual
   LISP Functions and FAS Compilation. http://www.caelink.com/
 CodeMagic
   Shareware text editor with AutoLISP syntax highlighting.

Old stuff:
 LispPad
   AutoLISP Editor by Tony Tanzillo.
 Visual LISP by WSSW
   Old small Windows LISP Editor, Version 1.0 was even free. See [1]
 WCEDIT 2.02
   Old ADS editor for DOS R12, can evaluate lisp code from within the
   editor, free.  See [1]
 CODEKEY
   Old commercial DOS IDE, internal pretty printer, protect, unprotect,
   kelvinator. Still available?
 ALLY 3.0 and CADET
   Shareware LISP Analyzer and Editor. See [6.2]
 pred
   free, small dos editor which provides parenthesis highlighting.
   At ftp://xarch.tu-graz.ac.at/pub/autocad/lsp_tools/pred.zip
   A similar editor is ADE.
 LSPEDIT from xlisp-stat
   A simple free Windows Lisp editor that supports parenthesis matching and
   code indentation.
   Check out http://www.stat.umn.edu/~luke/xls/xlsinfo/xlsinfo.html

 General customizable programming editors like MultiEdit Pro,
   WinEdit, E!, PFE, TextPad, UltraEdit or PFE are widely used also.
   They usually don't provide Lisp syntax checking or pretty printing,
   but (some even regular expression) multi-file search/replace and
   customizable syntax highlighting.

 There are others not that good (ADE) nor I don't have a description
 yet.

[6.2] Analyzers, Packagers and Parenthesis checkers
 Parenthesis checkers should not be used anymore. Editors should do the
 job. Analyzers generate a function cross-reference, the calling and the
 reverse callers tree. Packagers are used to generate libraries from
 various source files, copying all the needed functions.
 There's currently no code-walker which can internationalize command
 strings, but with R15 came a lisp analyzer (LCA).

 VLISP's [5.3] compiler analyses (compile with full messages) and
   checks parens <Ctrl-Alt-C>
 Reini's AutoLISP Packager
   http://xarch.tu-graz.ac.at/autocad/lsp_tools/#Packager
   Browsable function cross-referencer, reverse calling tree, creates a
   library from source files. ("Packaging" or "Function Shaker")
 PEI Findvars
   Similar to the Packager above, but not only functions, additionally
   detects symbols to be localized. http://www.perceptual-eng.com
   I personally use this.
 RapidLisp v1.0c [new]
   Shareware Lisp analyser f�r R14. http://www.cps.de/cad/rapidlisp/
 AVC - AutoLISP Variable Collector [new]
   Freeware, finds all variables to be declared per function.
   http://users.actcom.co.il/sysoft/vc.htm
 LCA - Autodesk's AutoLISP Compatibility Analyzer
   On the Migration CD. Details AutoCAD 2000 compatibility issues found
   in specified AutoLISP (LSP) or Menu LISP (MNL) files. (simple "Code Walker")

 ALLY30.ZIP (old)
   Shareware LISP analyser. Checks syntax and prints statistics, function
   dependence tree and used symbols, but no packaging. At [1]
 lck21b.zip (old)
   LCK LISP Checker 2.1b (graphical)
 paran.zip  (old)
   Simple
 PARNCH.ZIP (old)
   Simple
 There are also some AutoLISP programs which count parenthesis.

[6.3] Pretty Printers
 External:
   FMT202S.ZIP
     LISP, DCL and FRM source code formatter. Not checked yet.
   LB.EXE
     Autodesk's source code beautifier.
     In the SDK2 or at [1]. Has problems with longer strings,
     and new-style in-line comments.
   PPRINT.LSP
     In the SDK2, see [1.2], or at [1]
 Internal:
   Visual Lisp, Vital LISP, Emacs and Codekey provide internal
   beautifiers as I'm aware of it.

------------------------------

Subject: [7] AutoLISP problems and bugs

 For AutoCAD 2000 and unexperienced VLISP users see [0.1].
 There are almost no known serious AutoLISP bugs. The language
 interpreter itself (ACADL.EXE/.EXP, VLISP) works undoubtedly well.
 Some restrictions are based on the AutoCAD, ActiveX or the Proteus
 (DCL) engine. Some support LISP programs (i.e. DDMODIFY.LSP) are
 faulty sometimes.
 For Visual Lisp see the README.txt which lists all known bugs and
 limitations. Crashes with reactors are ACAD bugs.

 Two inofficial buglists are at:
 http://www.cadonline.com/exclusive/bugs/bugwatchlist.htm (the big one)
 http://www.dotsoft.com/buglist.htm (a private and short one)

 * LDATA  by Tom Berger     (VLISP for R14 and A2000)
   In short: Don't use LDATA at all. It may destroy DXF and DWG's
   in A2000. It is also VERY hard to get rid of them.

 * List Arguments with DOTTED PAIRS Passed from AutoLISP to
   Visual LISP or back may loose the outer parens.
   See the Visual Lisp README (undocumented in Vital Lisp)

 * SINGLE ATOM LISTS returned incorrectly from EXTERNAL APPS
   Visual LISP can not distinguish between a LIST of a single
   atom (element), and a single atom returned from an external
   ObjectARX or ADS application.

 * ENTGET used with LWPOLYLINE, HATCH  (R14 only)
   The Z coordinate (caddr (getval 10 ele)) is a random number and
   often causes a floating point exception because it may too low or
   too high. Workaround: see part 2, Subject [23.1]

 * ENTMAKE VERTEX  by Terry Dotson     (R14 only)
   A problem can occur during the process of using (entmake) to create
   polylines, you must assign the layer to each of the VERTEX
   definitions (which Autodesk has told us), but you must also assign
   the layer to the ending SEQEND. Absence of this will cause the SEQEND
   to end up on the current layer, which can be later frozen. Attempts to
   move this piece of geometry will then cause a EREGEN error and crash
   in R14 (only).

 * ACAD_STRLSORT: Strange sort order in Windows.
   The chars in Windows are not sorted on its ASCII representation!

     Windows: (acad_strlsort '("-1" "+1")) -> ("-1" "+1"),
     DOS:     (acad_strlsort '("-1" "+1")) -> ("+1" "-1")
     Both:    (mapcar 'ascii  ("-" "+"))   -> (45 43)
   More at http://xarch.tu-graz.ac.at/autocad/docs/strlsort-bug.html

 * AI_PROPCHK
   (ai_propchk) was renamed to (C:AI_PROP) in the R13c3 update
   patch. "The AutoLISP function ai_propchk has been changed to c:ai_prop
   so that it behaves similarly to other commands. This allows pressing
   return to bring back DDMODIFY if selected from the toolbar."

 * Faulty action callbacks in R13 DCL code crash AutoCAD
   There is a bug in R13 where AutoCAD crashes with a Fatal Error if
   an error occurs in AutoLISP code during an action callback from a
   scroll bar in a dialog box.  For instance, if you try to evaluate a
   null function during the callback, AutoCAD crashes instantly.
   Technically, this isn't a bug in the AutoLISP interpreter, but we
   would still call it an AutoLISP bug.

 * You cannot rely on bitvalue 64 in flag 70 in symbol tables anymore
   since R13, but in all previous releases. Inserted blocks may have
   64 not set.

 What else? See the unofficial AutoCAD buglist compiled by Steve
 Johnson for more faulty AutoLISP programs and behaviours, at
 http://www.cadonline.com/exclusive/bugs/bugwatchlist.htm

 * Protected LISP Files
   In pre-c4a R13 protected LISP files didn't stay protected in
   memory. In our opinion, this problem needs to be made known to all, so
   developers don't inadvertently assume their protected code is
   safe from prying eyes. This FAQ topic caused a major problem in
   moderated CompuServe's AutoCAD Forum.

 * Limited number of open selection sets
   They are intermediatly stored in temporary files. Get rid of not
   needed selection sets with setting the symbols to nil and run (gc),
   the garbage collector, which actually closes those files then.
   The maximal number depends on the operating system, i.e. in DOS
   of the FILES= value in CONFIG.SYS. R13 improved the number.

 * Numbers: range, accuracy, numerical precision
   Integer numbers are internal long fixnums (signed, 32-bit), but the
   communication from AutoLISP to AutoCAD accepts only 16-bit short
   fixnums, in the range -32768 .. +32767, because AutoCAD needs only
   short fixnums.
   Floating point numbers are doubles (64-bit IEEE). All internal
   AutoLISP and AutoCAD numerical calculations work with this double
   format, which should be sufficient. At least the first 14 decimal
   places are exact.
   A common problem is the confusion betwen the actual number (exact)
   and the rounded string representation. The number which is shown on
   the command-line is always the rounded string which takes care of
   LUPREC and DIMZIN.
   However with geometric comparisons there often occur round off errors,
   so that it's wise to compare points with a small fuzz factor
   [1e-12..1e-6].
     (equal pt1 pt2 1e-6)      ; 0.000001 rounding error tolerance
   instead of (equal pt1 pt2), esp. with angles.
   See also http://www.autodesk.com/support/techdocs/td30/td301207.htm

   VB: It was also reported lately, that with certain automation
   controllers loaded, numerical accuracy and locale issues (`,� vs `.�)
   had undesirable sideeffects. A solution and explanation of this
   problem is pending. (Mostly in `,� as decimal delimiter countries
   such as Germany)

 * ACOMP's (EQ) strictness
   With [5.1] ACOMP's compiled code you have to take care that the
   (EQ) behaviour in BI4's is much stricter than in plain AutoLISP. In
   AutoLISP (eq "1" "1") is T where in ACOMP's compiled code it's nil.

 The following are not real bugs, that make AutoLISP crash or return
 false results. They are just bad language implementations.

 * AND and OR should return the value of the not-NIL argument
   instead of T. See http://xarch.tu-graz.ac.at/autocad/docs/and-bug.html
 * MAX and MIN should handle string types too, because < and >
   accept and process strings types too.
 * see ACAD_STRLSORT above.
 * for stack overflow errors see [14]

------------------------------

Subject: [8] Sorting with AutoLISP

 In short: use VL-SORT (generic) or ACAD_STRLSORT (strings only),
 but beware: VL-SORT removes duplicate entries (which are EQ)!

 I've set up a AutoLISP sort overview at
   http://xarch.tu-graz.ac.at/autocad/lisp/#sort
 In LISP the mostly used sort method is merge sort (also used in
 (str-sort) in AutoDesk's TABLES.LSP sample) because that's a natural
 method for linked lists. Normally (e.g. in C) you use heap sort (for
 any data) or qsort (for random data) and insertion sort for the small
 lists (< 7) or sublists within the algorithm.

 There is a LISP code for shell-sort, bubble-sort, insertion-sort,
 quick-sort available for any data, lists of lists and indeces to
 lists. In LISP you can pass the predicate function to sort which is
 evaluated at run-time (here called 'method'). That's why you need
 only one sort function for multiple data types (i.e. numbers,
 points on x or y, strings, ...)

 (sort data method)    ;method: less-than-predicate
                       ;default for numbers: '<

 Some sample timings from
 http://xarch.tu-graz.ac.at/autocad/lisp/sort/ur_sort.lsp
 sorting 100 elements:
   bubble sort   : 13.639008 sec/ 30.08%
   insertion sort: 13.368042 sec/ 29.48%  (fast for sorted lists)
   shell sort    : 13.478973 sec/ 29.73%  (poor implementation)
   merge sort    :  2.232971 sec/  4.92%
   quick sort    :  2.433960 sec/  5.37%
   vl-sort       :  0.099976 sec/  0.22%  (Visual/Vital LISP internal)
   acad_strlsort :  0.089996 sec/  0.20%  (AutoLISP internal, strings)

------------------------------

Subject: [9] Recursion

 This is not an often asked question but a very interesting one,
 because LISP itself is defined recursively and it's often the
 easiest way to articulate hard problems.

 There some fine documents about recursion at
 http://xarch.tu-graz.ac.at/autocad/lisp/ especially the
 http://xarch.tu-graz.ac.at/autocad/lisp/recursive.html tutorial by
 Dennis Shinn.

 It explains in great detail:

 (defun fact (n)
   (cond
     ((zerop n) 1)
     (T (* n (fact (1- n))))))

 Note: There's also a self-modifying example of this function
 explained at http://xarch.tu-graz.ac.at/autocad/lisp/self-mod.lsp

------------------------------

Subject: [10] Iteration with MAPCAR,...

 Same as with recursion this is not a often asked question, but it's
 quite hard to understand too.
 Iterative statements in AutoLISP are: WHILE, REPEAT, FOREACH and
 MAPCAR. We use them widely in this FAQ code because they allow
 brief code.

 There's a short course in LAMBDA, QUOTE, MAPCAR... by Vladimir
 Nesterowsky:

 >>         "There are 14 paths and 12 pigs.
 >>         How can there be 24 ducks?"
 >> Is there a lisp command that will allow me to pick these
 >> lines of text, and recognize the number(s) in each line,
 >> in order to, say, raise each number by two?
 >> Leaving the sentence structure, etc, intact?
 This is one way. (I am sure there are many other ways)

 (defun mult2 (strng)          ; by Vladimir Nesterowsky
   (strlgather
     (mapcar
      '(lambda (s / n)
         (if (zerop (setq n (atof s)))
           s
           (rtos (* n 2))))
       (strlparse strng " "))  ; parse by spaces
     " "))                     ; gather back with spaces

is explained at http://members.tripod.com/~vnestr/mapcar.txt

 ;;; flip rows and columns in a matrix
 (defun transpose(l)           ; by Doug Wilson
   (apply 'mapcar (cons 'list l)))

is explained at http://xarch.tu-graz.ac.at/autocad/lisp/transpose.002.html

------------------------------

Subject: [11] S::STARTUP, My LISPs aren't loaded at startup anymore

 LISP files can be loaded at the startup using LOAD in ACAD.LSP.
 Some LISPs, required with a menu to work, should be loaded from
 the corresponding <menu>.MNL file. The <menu>.MNL file - if different -
 should load ACAD.MNL

 LISP functions calling commands at the startup should be defined in
 S::STARTUP of ACAD.LSP. This function is called at the startup
 after the initialization automatically. Otherwise you'll get the
 "Command list interruption (6 . 2)" errors.
 Note: (command) may be safely called from within MNL files.
 (S::STARTUP) is mainly used to check for partial menus now.

 If the file name was provided without an extension the LOAD function
 assumes .LSP. If - without a path prefix, the usual AutoCAD library path
 is used, which is
   1) The current directory
   2) The directory containing the current drawing file
   3) The directories defined in the ACAD environment variable
      (setup in the Preferences box, SUPPORT paths)
   4) The acad.exe directory
 If your program isn't loaded anymore automatically, check your AutoCAD
 library path settings.

 With ACADLC (of ACOMP) and the domestic release of AutoCAD R12 ACAD.LSP
 is not loaded automatically. Therefore you must append (load "ACAD" -1)
 to your ACAD.MNL.

 Sample ACAD.LSP:
 ;;;ACAD.LSP
 ;;; Fred the Beaver, 12/12/94
 (load "init" -1)                ; this loads some tools of mine
 (defun S::STARTUP ()
   (load "new-end" -1)           ; this redefines the END command
 )

 The -1 argument provides LOAD from interrupting the startup process, if
 any LOAD failure (causing an AutoLISP error). If a failure at the
 load-time occurs, -1 is returned, but the evaluation does not stop.
 -1 can be any expression as well.

 Sample code to enhance S::STARTUP in your code. With Visual LISP
 compiled code this will not work, it must be defined with DEFUN-Q
 instead. Functions are generally no lists anymore! Better than to
 use DEFUN-Q for S::STARTUP is to check for known hooks, a list of
 user-defined functions which are inserted and evaluated at run-time.

 (defun MY::STARTUP ()         ;your startup code goes here
   ;..
   (princ))

 (setq S::STARTUP
   (if (and S::STARTUP (listp S::STARTUP))     ;already defined in
                                               ; ACAD.LSP or elsewhere
     (append S::STARTUP (cdr MY::STARTUP))     ;append your code
     MY:STARTUP))                              ;just your code

 or a simple one:

 (if (and S::STARTUP (listp S::STARTUP))       ;usually called consp
    (setq S::STARTUP (append S::STARTUP (list func '(princ))))
    (setq S::STARTUP (list nil func '(princ))))

+ Vladimir Nesterovsky:
 The main difference now in A2K+ versions is that functions defined
 with DEFUN are now a new datatype, USUBRs, and not lists as before.
 But when the function is defined with DEFUN-Q, it is a list still,
 like in previous versions.

 Here's the utility function to use that works in both cases:

 (defun plug-into-startup (funcname) ;by VladimirNesterovsky
   "to be called with quoted function name"
   (eval (list
     'defun 's::startup ()
     (if s::startup (list (list 'quote s::startup)))
     (list funcname))))

 So if you have all your startup code packed into one routine

 (defun my-startup ()
   (alert "My Startup"))

 You make it work with the call

 (plug-into-startup 'my-startup)

 Inside your code that is executed on startup, e.g. acaddoc.lsp
 or whatever.

 See also  "[12] How to Autoload my programs?"

------------------------------

Subject: [12] How to Autoload my programs?

 How to load my programs automatically? You can either load your
 whole program at startup (see  "[11] My LISP doesn't
 load at startup anymore") which needs more time and memory at
 startup time, or you can define them via the autoloading mechanism.
 From R14 on ARX programs use a new autoloading scheme (called
 "demand loading") with some registry settings and not from ACADRxx.LSP
 anymore.

 Look at the end of your ACADRxx.LSP how AutoCAD autoloads its programs.

 ;;;===== AutoLoad LISP Applications =====
 ...
 (autoload "dline" '("dline" "dl"))
 ...

 This defines the commands DLINE and DL in the list to be loaded
 from the file DLINE.LSP when the user first calls the command DLINE
 or DL. Before that the function is simply defined like this one:

 (defun C:DL () (load "DLINE")(C:DL))

 In fact the definition is more complicated because of error
 handling.
 After the first call the function is overwritten with the
 definition in the program.

 Advantages of autoloading:
 * Startup is faster, because you dont have to load all your lisp
   files. You just define the simple *wrapper* definition as above.
   This is done by the (autoload) function.
 * You need less memory.

 Disadvantages:
 * On errors in your program you will fall into a never ending
   loop, which will only stop after a stack overflow or Ctrl-C
   Note: with ACOMP compiled code even Ctrl-C is impossible.
     Insert then a call to an uncompiled (princ) somewhere.
 * You have to define and maintain all command names from your
   program in the autoloader definition. Changes to the lisp
   filename or the command name will cause the above error.

 Where to put your (autoload) definitions?

 * Not to ACADR13.LSP.
 * Well we recommend putting it to an initialization file of yours
   and not to ACAD.LSP because this is often changed by different
   applications and ACAD.LSP should be kept rather small.
     I.e. put it to a AUTOLOAD.LSP or INIT.LSP, which is loaded from
   ACAD.LSP. See "[11] My LISP doesn't load at startup anymore"
 * It should be mentioned that users should *not* modify ACADRxx.LSP.
   Since ACAD.LSP is not overwritten during upgrades, it is guaranteed
   to remain safe. In addition (as we saw with the R13c4a patch) if the
   ACADR13.LSP file has been  modified, then the patch process may
   refuse to update it, thus resulting in program malfunctions.

------------------------------

Subject: [13] How can I pass a variable number of arguments to a lisp
function?

 With plain AutoLISP this is not possible.
 You can either pass all your arguments in a list like this:

 ;;; print a variable number of arguments (of any type)
 (defun my-princ (x)
   ;; simple version, for better stuff look at the SDK2: PRINTF.LLB
   (if (listp x)
     (mapcar 'princ x)
     (princ x)))

 Or you have to define the function in ADS and export it to
 AutoLISP.
 Then you are free to write:
   (ads-print "Hello " "World " 1 2 3)
 or even
   (ads-printf "Hello %s %i %i" "World" 2 3)

 Look at Reini Urban's and Vladimir Nesterovsky's ADS samples at
 http://xarch.tu-graz.ac.at/autocad/ads for implementations of the
 above examples.

 Official wishes were pointed to Autodesk regarding &optional as
 AutoLISP language enhancement, but it was not implemented in R14.

------------------------------
Subject: [14] How can I avoid stack overflows?

 In old AutoLISP the stack size was hardcoded. It couldn't be extended,
 but its size should be sufficient for most purposes. In the Visual
 Lisp IDE the stack overflow is simulated at 984 recursions, on the
 A2000 commandline or loaded programs outside the IDE there's no
 overflow anymore. This is dangerous on recursion errors of yours,
 see [9]. Most stack overflow errors occur on a program error of
 yours, preventing the system from falling into an endless loop, or
 from using recursive functions on large lists. Therefore you are
 limited to quite short lists with recursive functions and old versions.

 You cannot decrease your used stack size with using less local
 parameters in your recursive function! However do not use APPLY, EVAL
 or MAPCAR to call your function recursively, because they eat up the
 stack. Using tail recursion doesn't help either.
 You have to convert your recursive function to a iterative one.
 (There is a mathematical theorem that says, that every recursive
 function can be converted to a iterative one, tail-recursive ones
 even automatically.) Iterative versions may use stack-like functions
 like (push) and (pop), but those versions store the stack on the heap
 (autolisp node space), which size is only limited by your amount of
 virtual memory available.

 You can test the stack overflow with this simple function:

 ;;; create a list of n numbers (zero based)
 (defun intlst (l n)
   (cond ((zerop n) l)
         (T (intlst (cons (1- n) l) (1- n)))))
 and try:
 (setq n 100)(while (intlst nil (setq n (+ 10 n)))(print n))

 In AutoLISP of R12/DOS you reach the stack limit with
 (intlst nil 138), in A13/Win with (intlst nil 240), in ACOMP bi4's
 with (intlst nil 1240), in Vital LISP/Visual Lisp IDE with
 (intlst nil 984). With R10c10, the first dos extended lisp version,
 you could enhance the lisp stack size with the environment variable
 LISPSTACK. ACOMP for R10 had COMPSTACK.
 With Vital LISP or Visual LISP RTS or A2000 (outside the IDE) the
 stack size is unlimited.

 Conversion to an iterative version yields the required results:

 (defun intlst (n / l)
   (repeat n
     (setq l (cons (setq n (1- n)) l)))) ;this looks ugly but it works

------------------------------

Subject: [15] (command "ROTATE3D") does not work! Why?

 Some commands are no internal AutoCAD commands, they are simple
 AutoLISP programs beginning with C: even if they are defined in ADS
 programs. Only native Rx applications (or now with vlax-add-cmd)
 export true commands.

 A list of all these commands are found in ACADRxx.LSP in the
 AUTOLOAD section.  (see also "[12]")
 All these commands have to be called with (C:ROTATE3D) instead of
 (command "ROTATE3D").
 However ADS functions may take optional arguments. See the
 customization manual for more.
 i.e. (c:rotate3d ss p1 p2 angle) is also valid, even (rotate3d ...)

------------------------------

Subject: [16] LISP programs operating over multiple drawings

 "I am having trouble getting a lisp file that will open a drawing and
 continue running. Once the new drawing is opened the LISP file ceases
 to exist in the Autocads memory. It has to be reloaded to recognise
 the commands."

 LISP memory is reloaded on a per drawing basis.  There are some
 ways to execute a LISP on multiple drawings:
 1) via a script that executes on multiple files.
    MYSCRIPT.SCR:
    (load "mylisp")
    _QSAVE _OPEN !nextdwg
    (load "mylisp")
    _QSAVE _OPEN !nextdwg
    ...
  2) External 3rd party software such as RunLisp, ScriptPro or DDSCRIPT automate
     step 1.
  3) R14 has a new feature, called 'Persistent LISP'.
     Set it in Preferences-Compatibility-Persistent LISP
  4) Vital LISP has a built-in variable to act as Persistent LISP:
     (setq *VILL-NEW-FULL-INIT* nil)   ;keep symbols between sessions
  5) same with Visual LISP: (setq *VLISP-NEW-FULL-INIT* nil)

------------------------------

Subject: [17] How to export Visual Lisp functions to AutoLISP/AutoCAD?

C: functions are automatically exported to AutoLISP. Plain vlisp/vill
lisp functions must be exported either with (vl-acad-defun funcname) or
their symbols may be exported with a special compiler pragma, defined
either in the LSP file or in the GLD (global declarations) file. Better
use special prefixes for such functions.

GLD:
(AUTOEXPORT-to-ACAD-PREFIX
 ;| name prefixes for functions to be autoexported to AutoCAD: (strings) |;
 "myx-*"
 )
or one by one
LSP:
(pragma '((export-to-acad myx-func1 myx-func2)))

Note: There may exist known bugs in vlisp and vill with lists of atomic
symbols and dotted pair lists in such functions arguments and return
values. See [7].

Functions exported by external apps which are used in your application
must be defined via XDF.

Symbols (variables) whose values are updated in Visual Lisp and which
values are also used in AutoLISP or AutoCAD (the menu e.g.), first may
be marked for the compiler to be external with:
 (pragma '((not-localize myx:symbol)))
but the value must be exported with
 (vlisp-export-symbol 'myx:symbol)
each time the value is changed in Visual Lisp and control is returned
to AutoCAD to be able to get the latest value in AutoLISP or in AutoCAD
with !myx:symbol

You may forget this whole chapter with AutoCAD 2000, however you might
need to export your function from the protected namespace then with
VL-DOC-SET.
See also http://www.autodesk.com/support/techdocs/td17/td175363.htm

------------------------------

Subject: [A] Disclaimer, Notes from the authors

 If you think of questions that are appropriate for this FAQ, or
 would like to improve an answer, please send email to Reini Urban
 <[email protected]> but don't expect an reply.

 This AutoLISP FAQ is Copyright (c) 1996,97,98,99,2000 by Reini Urban.

 This FAQ may be freely redistributed in its entirety without
 modification provided that this copyright notice is not removed. It
 may not be sold for profit or incorporated in commercial documents
 (e.g. published for sale on CD-ROM, floppy disks, books, magazines,
 or other print form) without the prior written permission of the
 copyright holder. Permission is expressly granted for this document
 to be made available for file transfer from installations offering
 unrestricted anonymous file transfer on the Internet and esp. to be
 included into the official AutoCAD FAQ.

 The sample code is, if not otherwise stated, (c) 1996,97
 by Reini Urban and may be freely used, but not sold.
 The basic functions in [20] are, if not otherwise stated, (c) 1991-97
 by Reini Urban and may/should be freely used.

 If this FAQ is reproduced in offline media (e.g., CD-ROM, print
 form, etc.), a complimentary copy should be sent to Reini Urban,
 X-RAY, Nibelungeng. 3, 8010 Graz, Austria

 This article, the contents and the sample code, is provided AS IS
 without any expressed or implied warranty.

[A.1] FAQ Locations

 Homepage of the HTML'ified version:
   http://xarch.tu-graz.ac.at/autocad/news/faq/autolisp.html
+ Annotated AcadWiki version:
+   http://xarch.tu-graz.ac.at/acadwiki/AutoLispFaq
 The posted ascii versions (and always latest versions) are at
   http://xarch.tu-graz.ac.at/autocad/news/faq/autolisp.1 and
   http://xarch.tu-graz.ac.at/autocad/news/faq/autolisp.2
 The Winhelp version (zipped with faq and code) is at
   ftp://xarch.tu-graz.ac.at/pub/autocad/news/faq/autolisp.zip
 The FAQ usenet archive is at
   http://www.faqs.org/faqs/CAD/autolisp-faq/ resp.
   ftp://rtfm.mit.edu/pub/usenet-by-hierarchy/comp/cad/autocad/
 The LISP code from this FAQ is at
   ftp://xarch.tu-graz.ac.at/pub/autocad/news/faq/FAQ-CODE.LSP
 See also the cca glossary for common abbrevations at
   http://xarch.tu-graz.ac.at/autocad/news/faq/glossary.html
 Submissions for a new AutoCAD FAQ are stored at
   http://xarch.tu-graz.ac.at/autocad/news/faq/new-acad
 A french translation of the FAQ was made by Roger Rosec
   http://www.newz.net/acadplus/page5101.htm
 A japanese translation of the FAQ was made by MASAMI Chikahiro
   http://www.page.sannet.ne.jp/chestnutsburr/autolisp-j.html
 A russian translation by Igor Orellana at
   http://www.cad.dp.ua/stats/alfaq_ru.htm
 A german translation by myself at
   http://xarch.tu-graz.ac.at/autocad/news/faq/autolisp.html.de
+ A new spanish translation by Eduardo Magdalena
+   http://www.peletash.com/mecanicad/articulos/art02_0002.htm

 A greek translation is in progress.
 Relevant AutoDesk FAQ's and TechSupport
   http://www.autodesk.com/support/autocad/
   http://search.autodesk.com/query.html?qt=autocad+faq
   http://www.autodesk.com/support/autocad/asa2000.htm
 AutoDesk news groups
   news://discussion.autodesk.com/autodesk.autocad.customization
   New WebX interface at http://discussion.autodesk.com
   http://groups.google.com/groups?oi=djq&as_ugroup=autodesk.autocad.customization

--
Reini Urban, Jun 25, 2002