Io is a dynamic prototype-based programming language. The ideas in Io are mostly inspired by Smalltalk (all values are objects), Self (prototype-based), Newton Script (differential inheritance). Io is a prototype-based programming language inspired by Smalltalk (all values are objects, all messages are dynamic), Self (prototype-based), NewtonScript (differential inheritance), Act1 (actors and futures for concurrency), LISP (code is a runtime inspectable/modifiable tree) and Lua (small, embeddable). In Io, all values are objects (of which, anything can change at runtime, including slots, methods and inheritance), all code is made up of expressions (which are runtime inspectable and modifiable) and all expressions are made up of dynamic message sends (including assignment and control structures).
user@computer:~$ io Io> write("Hello, world!\n") Hello, world! ==> nil