Short syntax thing or instance variable

[joente]

Is your feature request related to a problem? Please describe.
When creating a Type instance or a new thing, we quite often write something like:

Person{name: name};

where we need to write name twice, once as key and the other for the var which we use.

Describe the solution you'd like
I would like a syntax so we could write name only once using the syntax:

Person{name:};

I would like to add the : since it otherwise becomes confusing and (almost) incompatible with a block { .. } and/or enum {name}.

Multiple short and long syntax must also work, for example:

{
  color:,
  size:,
  description: 'This is just an example'
}

Describe alternatives you've considered
I've considered removing the : but require a , if only one variable will be used. This however is way more complex to parse. I've also considered to start with a : followed by the name, thus: Person{:name}. I think however that the suggested option is better, especially when using a combination of short and long syntax.