Smalltalk

From APIDesign

Dissatisfied with relational or OOP mappings of the real world? Let's create our own world inside a computer. Let's write in Smalltalk!

I don't like that each Smalltalk system ends up being completely unique, as it is common to add new and new methods to the base Object. Usually things like isInteger, isString, etc. This is not how APIs should be designed, as that prevents merge of systems developed independently, imho.

However I like Smalltalk's Hotswap. Long time ago Smalltalk could do things Java is still dreaming about.