Everything is an object
In Crystal everything is an object. The definition of an object boils down to these points:
- It has a type
- It can respond to some methods
This is everything you can know about an object: its type and whether it responds to some method.
An object's internal state, if any, can only be queried by invoking methods.
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https://crystal-lang.org/reference/syntax_and_semantics/everything_is_an_object.html