[OpenSCAD] Questions from a new user

Thu Mar 11 09:34:03 CET 2010

On Wed, 2010-03-10 at 22:02 -0500, Jeff Newbern wrote:
> Hello,
> 
> I've just picked up OpenSCAD and I'm enjoying exploring the tool.  I
> can see that it has great potential, but I'm being slowed down by the
> lack of a thorough reference for the scripting language.  I have a few
> questions that I hope experienced users on this list will be able to
> answer easily.

Have you read http://en.wikibooks.org/wiki/OpenSCAD_User_Manual ?

> First, it seems that the syntax for function declarations is:
> 
>         function <name>([<formal arguments>]) = <expression> ;

not really the syntax is

      function <name>(<arguments>) = <expression> ;

e.g.  r_from_dia(d) = d/2;

> Is there a ternary operator (something like <cond> ? <true_expr> :
> <false_expr>) so that function return values can be conditional? 

yes there is an undocumented ternary operator the syntax is as you say
the only thing I have found is sometimes you need extra brackets

e.g.    (a==1) ? "True" : "False"

or	(a>7) ? (d/2) : (d/3);

>  Alternatively, is there a function syntax similar to:
> 
>         function <name>([<formal arguments>]) {
>           <body>
>         }
>
> where the function body can contain an if-else tree with return
> <expression> statements?

I don't think there is yet.

> The other thing which seems like it would be useful is to be able to
> query the bounding volume for an object.  This would let me write
> functions to automatically align, center, etc. collections of objects.
> 
> Also, if you have any general tips for a new user (coding style,
> proper composition, best practices, etc.) I'm sure I would benefit
> from your experience.
> 
> Thank you,
> Jeff
> 
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