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From: Mensanator on 26 Sep 2009 18:22
On Sep 26, 2:14�pm, Rui Maciel <rui.mac...(a)gmail.com> wrote:
> John Slimick wrote:
> > I never saw LISP as a serious production language,
>
> AutoCAD has a considerable chunk of it written in lisp (well, a lisp dialect) and also relies on it for
> scripting.
>
> That is as serious as any production language can get.

Why the change to Visual Basic then? Is it because
lisp is too hard for your everyday CAD person
to understand?

>
> Rui Maciel

From: bartc on 26 Sep 2009 19:43
Mensanator wrote:
> On Sep 26, 2:14�pm, Rui Maciel <rui.mac...(a)gmail.com> wrote:
>> John Slimick wrote:
>>> I never saw LISP as a serious production language,
>>
>> AutoCAD has a considerable chunk of it written in lisp (well, a lisp
>> dialect) and also relies on it for scripting.
>>
>> That is as serious as any production language can get.
>
> Why the change to Visual Basic then? Is it because
> lisp is too hard for your everyday CAD person
> to understand?

I'd also thought that AutoLisp had long since been superceded, but
apparently it's still going strong.

It originally seemed a very odd choice for a user's scripting language for
CAD, but perhaps someone thought that the DWG data structures (hierarchical
lists of objects) were well represented with Lisp lists.

I'm sure it did the job admirably (although when I added a user-language to
my own CAD product, I think my users appreciated a more conventional
language).

--
Bartc

From: Pascal J. Bourguignon on 26 Sep 2009 21:11
Mensanator <mensanator(a)aol.com> writes:

> On Sep 26, 2:14�pm, Rui Maciel <rui.mac...(a)gmail.com> wrote:
>> John Slimick wrote:
>> > I never saw LISP as a serious production language,
>>
>> AutoCAD has a considerable chunk of it written in lisp (well, a lisp dialect) and also relies on it for
>> scripting.
>>
>> That is as serious as any production language can get.
>
> Why the change to Visual Basic then? Is it because
> lisp is too hard for your everyday CAD person
> to understand?

Yes. http://www.imdb.com/title/tt0387808

--
__Pascal Bourguignon__
From: Rui Maciel on 27 Sep 2009 05:25
bartc wrote:

> It originally seemed a very odd choice for a user's scripting language for
> CAD, but perhaps someone thought that the DWG data structures
> (hierarchical lists of objects) were well represented with Lisp lists.

It may appear that a lisp dialect is an odd choice for a scripting language but, for that particular type of
application, it was undoubtedly the right choice. Basically, a vector graphics document is nothing more than
a long list of a series of drawing objects which are organized hierarchically. So if you need to script that
sort of application, which means that basically all you need to do is operate on lists, then a list processor
is exactly what you are looking for.


Rui Maciel
From: bartc on 27 Sep 2009 06:47

"Rui Maciel" <rui.maciel(a)gmail.com> wrote in message
news:4abf2fa1$0$23094$a729d347(a)news.telepac.pt...
> bartc wrote:
>
>> It originally seemed a very odd choice for a user's scripting language
>> for
>> CAD, but perhaps someone thought that the DWG data structures
>> (hierarchical lists of objects) were well represented with Lisp lists.
>
> It may appear that a lisp dialect is an odd choice for a scripting
> language but, for that particular type of
> application, it was undoubtedly the right choice. Basically, a vector
> graphics document is nothing more than
> a long list of a series of drawing objects which are organized
> hierarchically. So if you need to script that
> sort of application, which means that basically all you need to do is
> operate on lists, then a list processor
> is exactly what you are looking for.

Thinking about it some more, I'm not at all sure that drawing data would
have been accessed via 'live' list objects of the language (except in the
unlikely scenario that Lisp was also used in the display engine or the
internal DWG format happened to be in the form of Lisp objects).

When I did this stuff, I used iterator functions to traverse the drawing
data, so any dynamic language would have done.

--
Bartc

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