I believe it's called Domain-Specific Language (DSL) and there are systems that excel at quickly, easily and reliably creating these languages, for example Groo

I believe it's called Domain-Specific Language (DSL) and there are systems that excel at quickly, easily and reliably creating these languages, for example Groovy. You could write a language like in your example, and it would be usable and stable in a couple of hours. Then you could script all kinds programs in it quickly, while also being able to leverage the rest of the flexibility of the Groovy language, interchaning its code with DSL statements.