On 09/13/2016 12:49 PM, clipka wrote:
> Am 13.09.2016 um 17:51 schrieb William F Pokorny:
>
>>     pigment {
>>       potential { BLOB | ISOSURFACE }
>>       [ threshold BOOL ]
>>       [ PIGMENT_MODIFIERS... ]
>>     }
>>
>> Looking just at simple blob so far I see a few things.
>>
>> 1) Wondering it the option [threshold BOOL] should be inside the
>> potential block syntactically?
>
> No; the braces around the BLOB or ISOSURFACE are just around the BLOB or
> ISOSURFACE. Strictly speaking, the syntax is
>
>     pigment {
>       potential { BLOB | ISOSURFACE [ OBJECT_MODIFIERS... ] }
>       [ threshold BOOL ]
>       [ PIGMENT_MODIFIERS... ]
>     }
>
> (for reasons only disclosed to Disciples of the Inner Sanctum), and the
> only reason the braces are there at all is to unambiguously mark the end
> of OBJECT_MODIFIERS, so that there is no ambiguity for statements that
> may be both valid OBJECT_MODIFIERS and PIGMENT_MODIFIERS.
>
> There is a long-standing tradition that pattern parameters are placed on
> the same hierarchical level as pigment/normal/texture/whatever
> modifiers, and `potential` honors this tradition. (Don't be fooled by
> the syntax of the `object` pattern, it is the odd one out and should
> never have been implemented this way in the first place.)
>
OK. Thanks.

Bill P.

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