Harbour is a computer programming language, primarily used to create database/business programs. It is a modernized, open source and cross-platform version of the older Clipper system, which in turn developed from the dBase database market of the 1980s and 1990s.
Harbour code using the same databases can be compiled under a wide variety of platforms, including Microsoft Windows, Linux, Unix variants, several BSD descendants, Mac OS X, MINIX 3, Windows CE, Pocket PC, Symbian, iOS, Android, QNX, VxWorks, OS/2 (including eComStation and ArcaOS), BeOS/Haiku, AIX and MS-DOS.
History
The idea of a free software Clipper compiler had been floating around for a long time and the subject has often cropped up in discussion on comp.lang.clipper. Antonio Linares founded the Harbour project and the implementation was started in March 1999. The name "Harbour" was proposed by Linares, it is a play on a Clipper as a type of ship. Harbour is a synonym for port (where ships dock), and Harbour is a port of the Clipper language.
In 2009, Harbour was substantially redesigned, mainly by Viktor Szakáts and Przemyslaw Czerpak.
Database support
Harbour extends the Clipper Replaceable Database Drivers (RDD) approach. It offers multiple RDDs such as DBF, DBFNTX, DBFCDX, DBFDBT and DBFFPT. In Harbour multiple RDDs can be used in a single application, and new logical RDDs can be defined by combining other RDDs. The RDD architecture allows for inheritance, so that a given RDD may extend the functionality of other existing RDD(s). Third-party RDDs, like RDDSQL, RDDSIX, RMDBFCDX, Advantage Database Server, and Mediator exemplify some of the RDD architecture features. DBFNTX implementation has almost the same functionality of DBFCDX and RDDSIX. NETIO and LetoDB provide remote access over TCP protocol.
Harbour also offers ODBC support by means of an OOP syntax, and ADO support by means of OLE. MySQL, PostgreSQL, SQLite, Firebird, Oracle are examples of databases which Harbour can connect to.
xBase technologies often are confused with RDBMS software. Although this is true, xBase is more than a simple database system as at the same time xBase languages using purely DBF can not provide the full concept of a real RDBMS.
Programming philosophy
Harbour aims to be written once, compiled anywhere. As the same compiler is available for all of the above operating systems, there is no need for recoding to produce identical products for different platforms, except when operating system dependent features are used. Cross-compiling is supported with MinGW. Under Microsoft Windows, Harbour is more stable but less well-documented than Clipper, but has multi-platform capability and is more transparent, customizable and can run from a USB flash drive.
Under Linux and Windows Mobile, Clipper source code can be compiled with Harbour with very little adaptation. Most software originally written to run on Xbase++, FlagShip, FoxPro, xHarbour and others dialects can be compiled with Harbor with some adaptation. As of 2010 many efforts have been made to make the transition from other xBase dialects easier.
Harbour can use the following C compilers, among others: GCC, MinGW, Clang, ICC, Microsoft Visual C++ (6.0+), Borland C++, Watcom C, Pelles C and Sun Studio.
Harbour can make use of multiple Graphical Terminal emulation, including console drivers, and Hybrid Console/GUIs, such as GTWvt, and GTWvg.
Harbour supports external GUI's, free (e.g. HBQt, HWGui, Mini-GUI (latest version based on Qt and QtContribs) and commercial (e.g. FiveWin, Xailer). HBQt is a library providing bindings to Qt. HBIDE application is a sample of HBQt potential.
Harbour is 100% Clipper-compatible and supports many language syntax extensions including greatly extended run-time libraries such as OLE, Blat, OpenSSL, Free Image, GD, hbtip, hbtpathy, PCRE, hbmzip (zlib), hbbz2 (bzip2), cURL, Cairo, its own implementation of CA-Tools, updated NanFor libraries and many others. Harbour has an active development community and extensive third party support.
Any xBase language provides a very productive way to build business and data intensive applications. Harbour is not an exception.
Macro Operator (runtime compiler) One of the most powerful features of xBase languages is the Macro Operator '&'. Harbour's implementation of the Macro Operator allows for runtime compilation of any valid Harbour expression. Such a compiled expression may be used as a VALUE, i.e. the right side of an assignment (rvalue), but such a compiled expression may be used to resolve the left side (lvalue) of an assignment, i.e. private, or public variables, or a database field.