Actually these days the official moniker is CA-Clipper. (This is just as well since the US Government and its contractors have appropriated the name "Clipper" to apply to an encryption scheme that has nothing to do with our programming language.)
Clipper is a programming language, and it is also a compiler. The programming language is a superset of dBASE III+, and also shares some features with C/C++ and Smalltalk. It is a general-purpose, high-level programming language well suited to corporate and commercial applications development.
CA-Clipper is also a compiler product marketed by Computer Associates, the second largest software vendor in the world today. The CA-Clipper compiler is (by definition) a fully conformant implementation of the CA-Clipper programming language for IBM-PC-type personal computers running DOS-like operating systems.
There are other Clipper implementations, from vendors other than Computer Associates, that have varying capabilities and run on platforms other than MS-DOS.
Clipper, the compiler from Computer Associates? Well, it's definitely stopped evolving; CA has announced that 5.3 will be the last significant release and only maintenance patches will be forthcoming. There is still (as of March 1998) a lot of maintenance work for good Clipper programmers. And when you do write that occasional new DOS program (some of us still do!), Clipper is an outstanding choice. But for most programmers in business today, yeah, there are really not too many applications that you would write from scratch with Clipper.
Clipper, the language? Definitely not obsolete. Clipper clones, improvements, and adaptations are everywhere. I count FlagShip, xBase++, x2c, FORCE, and Visual Objects (sorta) at least. Almost all desktop operating systems in common use have a "Clipper" of some kind. As long as people are using Windows NT, Windows 95, OS/2, or Unix, there will be a Clipper.
CA-Visual Objects is an object-oriented Windows-based applications development environment with repository-based source management and an incremental compiler. It includes interfaces to many major database engines via the ODBC (Open DataBase Connectivity?) standard.
The compiler itself supports a hybrid of xBase and C/C++ techniques; it will, for example, generate straight machine code instead of pseudo-code if you supply proper typing information or if it can figure this out from context.
CA-Visual Objects is the spiritual descendant of Nantucket's old "Aspen" project.
At the moment 5.3b is current, and it is the only release you can get through the standard distribution channels. Many programmers are still working with 5.2e. You can get a patch that brings any 5.2ish Clipper installation to 5.2e, but you cannot buy 5.2 itself through normal distribution channels.
The 16-bit version of CA-Visual Objects is 1.0, currently patched to 1.0d. You can get the patch set from any 1.0 release to 1.0d on CD-ROM or floppies from Client Care, download it from the VOFORUM forum on Compuserve, or download it from the Computer Associates FTP site
The current 32-bit release is 2.0b-1. You can get patches for both VO 2.0-b1 Professional and VO 2.0-b1 Standard.
This is available from any reasonably large mail-order vendor. You don't see CA-Clipper in computer stores very often though.
The patch to 5.3b is available with documentation.