POV-Ray : Newsgroups : povray.beta-test : POV-Ray v3.8.0-alpha.9945627 : Re: POV-Ray v3.8.0-alpha.9945627 Server Time
24 Jun 2021 07:15:36 EDT (-0400)
  Re: POV-Ray v3.8.0-alpha.9945627  
From: clipka
Date: 4 Dec 2018 23:24:21
Message: <5c0752f5$1@news.povray.org>
Am 05.12.2018 um 01:24 schrieb jr:
> hi,
> 
> clipka <ano### [at] anonymousorg> wrote:
>> https://github.com/POV-Ray/povray/releases/tag/v3.8.0-alpha.9945627
> 
> this version allows me to omit a comma in a dictionary, I'm guessing that's
> unintended?
> 
> #declare X = dictionary {
>    .v0 : array
>    .v1 : 0,
>    .v2 : 1
> };
> 
> same for x.tokenizer.9945666.
> 
> regards, jr.

No, that's entirely intentional. Commas are always optional, provided 
that this doesn't lead to ambiguity.

For example, the following will NOT work:

     #declare Foo = <1,2,3>;
     #declare X = dictionary {
        .v0 : Foo
        .v1 : 0,
        .v2 : 1
     };

That's because `Foo` is a vector, so POV-Ray would misinterpret the `.` 
in `.v1` as belonging to `Foo`, and expect either `x`, `y`  or `z` to 
follow. Placing a comma after `Foo` indicates to POV-Ray that this 
expression is completed.


As another example, consider the following:

     #declare Foo = <1 2 3>;

This will declare a 3-dimensional vector. On the other hand, the 
following will declare a 2-dimensional vector:

     #declare Foo = <1 -2 3>;

That's because POV-Ray interprets `1 -2` as the expression `1-2`, i.e. 
the single value -1.


Post a reply to this message

Copyright 2003-2021 Persistence of Vision Raytracer Pty. Ltd.