Clipper programming language
Clipper is a computer programming language that is used to create software programs that operate primarily under DOS. Although it can be used as a general-purpose programming tool, it is almost exclusively used to create database programs.Clipper was originally created strictly as a compiler for dBASE code. Compiling changes dBASE code from interpreted code, which must be interpreted every time the line of code is executed, to P-Code (or pseudo-code), which requires interpretation less often and thus is considerably faster in execution, but still not as fast as the machine code generated by native compilers. Clipper was created by a company named Nantucket, and later sold to Computer Associates.
As the product matured, it remained a DOS tool, but added elements of the C programming language and Pascal programming language, as well as the unique code-block data-type (hybridizing the concepts of dBase macros, or string-evaluation, and function pointers), to become more powerful than the original. Nantucket's Aspen project later matured into the Window's native-code compiler Visual Objects.
As of this writing (2003), the language has not been updated in several years but is still actively used, and many variants are being created, such as Xbase++, Harbour. Libraries that allow Clipper to create Windows programs are also available, principally FiveWin and Clip4Win.