overview Io is a small, prototype-based programming language. The ideas in Io are mostly inspired by Smalltalk (all values are objects), Self (prototype-based), NewtonScript (differential inheritance), Act1 (actors and futures for concurrency), LISP (code is a runtime inspectable/modifiable tree) and Lua (small, embeddable).
features open source BSD license
small VM (~10K C statements, 5K Io specific)
reasonably fast (comparable to Python, Perl, Ruby)
incremental collector, weak links
dynamic typing
C99 implementation
multi-state (multiple VMs can run in the same application)
actor-based concurrency, coroutines
64 bit clean
platforms OSX, Linux/FreeBSD/NetBSD/Irix/Solaris, Windows, Symbian, Syllable
bindings async sockets and dns
SQLite and SkipDB (embedded transactional databases)
regular expressions (Perl 5 compatible)
xml/html/sgml parsing
md5, sha1, zlib, lzo, blowfish
curses (text interfaces)
FreeType (TrueType antialised font support)
Objective-C bridge
more sample code, tutorial, manual, reference docs