The Commander application is a generic VFP programming utility for creating and running table-driven functions.  It supports optional user-defined arguments, return values, error handling, and nested or recursive functions.  Instead of using the conventional model of program "source files" (e.g. PRGs) that are compiled into "object files" (e.g. FXPs), Commander uses a meta-file to store an arbitrary sequence of VFP command lines within a VFP table.  When a Commander-based function (a "pseudo-function") is evaluated, the steps defined in the meta-file are executed in sequence, without the need for compilation.

Although Commander is a modular, general-purpose facility, its primary raison d'être is to support the core state-saving and restoration features of the Saver subsystem.  The chief benefits of using Commander are:

• simplified programmatic generation of executable function definitions
• performing queries and reports against functions, treated as data
• updating function definitions via powerful database operations
• flexible, dynamic functions in a pure VFP Runtime environment

VFP's compiled procedures are unquestionably faster than equivalent Commander pseudo-functions, but in many cases this difference will make a negligible contribution to an application's overall performance.  When the flexibility of Commander's table-driven model can be put to good use, it should be considered as an alternative to traditional compiled programs.

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