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Unlike the ordinary class inheritance, each variant is signed with a variant condition.
This condition determines when the variant will be used in order to substitute its
origin definition. Only if the condition is fulfilled, the affected variant is applied. In this
manner, multiple variants can be implemented and the user can switch between
them. The condition accepts a list of profile and style names. The condition is fulfilled,
if one of the specified profiles or styles is selected.
The variant condition is evaluated as well as during the code generation and at the
runtime. If the condition is fulfilled already during the code generation, the affected
variant does substitute its origin definition permanently – it can’t be switched at the
runtime anymore. Such kind of a variant is called 'static' variant. Usually its condition
depends on a profile, which is then selected for the code generation.
The second kind is called 'dynamic' variants. Dynamic variants can be switched at
the runtime, if the appropriate variant condition depends on one of the active styles.
The activation and deactivation of styles is performed by assigning a set of style
names to the global built-in Chora variable styles. For example, the both styles
AquaLook and WideScreen are activated in the following manner:
styles = [AquaLook, WideScreen];
Alternatively the variant condition can be set to the literal true. In this case the
variant substitutes its origin definition permanently, independent from any profiles or
styles. For more details about profiles and styles  see "Profiles and macros"
(chapter 3.2) and "Styles" (chapter 3.4)
If the variant condition is set to the literal default, the variant substitutes its origin
definition only when no other variant is available.
Alternatively the variant condition can be set to the literal true. In this case the
variant substitutes its origin defintion permanently, independent
If the condition of a variant is never fulfilled, no code is generated for the affected
variant. This automatic elimination reduces the memory footprint of Chora programs.
If two variants of the same origin definition depend on the same variant condition, a
Chora compiler error is reported, because the Embedded Wizard is not able to
distinguish between those both variants.
It is also possible to derived variants from other variants. So complex variant
hierarchy is possible. For more details  see "Usage of Variants" (chapter 10).
4.8.1 Class Variants
Class variants are always introduced by the keyword vclass, followed by the name
of the variant and the name of the origin class (the ancestor):
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