Having GUI tooling to inspect, debug and develop integrated in the execution environment is kind of Smalltalk's thing. It's like a Common Lisp with more clicking in that regard.
It's rather neat, and means you can extend your development environment in the same way you develop your applications. If you want to extend the inspector for a particular type of object you can do that. Compared to writing plugins for Eclipse or IntelliJ it's a trivial exercise.
GT does it too, though explicitly aimed at tool development rather than application development: https://gtoolkit.com/
In a sense it's the original vibe coding environment.
It's rather neat, and means you can extend your development environment in the same way you develop your applications. If you want to extend the inspector for a particular type of object you can do that. Compared to writing plugins for Eclipse or IntelliJ it's a trivial exercise.
GT does it too, though explicitly aimed at tool development rather than application development: https://gtoolkit.com/
In a sense it's the original vibe coding environment.