My definition of expressiveness is basically similar to what Paul Graham (@pg) says. He also calls this "powerfulness" in his famous "Beating the averages" essay[1]. In short, a more expressive language is a language that lets you express more with less. Rails, with its "has_many :books" is very expressive, Assembly is the other end.
The wizarding/engineering spectrum was coined by the article I've linked to[2]. I think the post is exactly about that, first Instagram was wizarding and they had a suitable language for wizarding, now they're engineering, but their language is still only good for wizarding.
As I've said in a sister comment, it's not just about static typing, but metaprogramming/macros/side effects everywhere etc. There's more to the expressiveness/powerfulness than just types. While gradual typing is certainly an improvement, I think we need more research in this direction.
The wizarding/engineering spectrum was coined by the article I've linked to[2]. I think the post is exactly about that, first Instagram was wizarding and they had a suitable language for wizarding, now they're engineering, but their language is still only good for wizarding.
As I've said in a sister comment, it's not just about static typing, but metaprogramming/macros/side effects everywhere etc. There's more to the expressiveness/powerfulness than just types. While gradual typing is certainly an improvement, I think we need more research in this direction.
[1] http://www.paulgraham.com/avg.html