PropXX Flexible, high-performance configuration utility for C++

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About PropXX

PropXX provides a property/configuration mechanism for C++ applications. Properties can be defined in files similar to but more flexible than Java properties:

• Property files are not only plain text but have a structure that is defined through a property set definition. This provides type safety, expressive error messages and modularization of large property sets.
• Property settings can be also be modularized and property values can flexibly defined in a configuration language with full-featured expressions, a powerful comment syntax etc.
• The configuration languages for both property set definitions and property files is implemented as internal DSL in the Lua language.

The design of PropXX combines flexibility with high-performance for the C++ code which accesses property values. The property values are stored in objects of special property classes which are automatically generated from the property set definitions. Performance-critical code can be inlined by the compiler and a typical access to a property value is as cheap as reading a single variable from the memory. No costly data structures like hashes or balanced trees etc. are involved.

Since both the generated property classes and the embedded Lua interpreter are very light-weight and portable, PropXX can be used with practically any C++ project. In particular, it would make perfect sense to use it for embedded systems with very limited hardware resources.

Features

• Configuration files for C++ similar to Java properties
• High performance through tuned, auto-generated C++ code
• Flexible, type-safe, programmable property definitions
• Based on Lua scripting language
• Portable. Generated code uses only simple C++ features. No dependencies besides Lua (which requires only ANSI-C).
• Extensible with own property types (planned for full-release)
• Graphical user interface for end-users (who shall not edited properties directly in a text editor)

Keywords:Lua, C++, Java properties, property files, parser, configuration language, library, Open Source, code generation, high performance, flexible, portable, embedded.

License

PropXX is distributed under the GNU General Public License v3. The C++-part is also available under the terms of the GNU Lesser General Public License v3. This permits using PropXX in commercial, closed-source applications as long as the set of available C++ property classes is not extended.

Download

PropXX is available for download at the Sourceforge project page.

The feature set which was planned for the first release 1.0 is almost complete and PropXX is thus considered ready for productive use. PropXX has been tested with a quite comprehensive test suite.

Since high quality of the code is our main goal, please don't hesitate to report any issues that you might encounter. In general, any feedback is highly welcome. You may consider using the Sourceforge tracking utility or the forums

Dependencies

• PropXX is based on Lua. We currently use Lua 5.1.3.
• The C++ library is currently built and tested under Linux but should work on most UNIX systems. The GNU Build Tools (autoconf 2.61 and automake 1.10.1) are used to achieve this portability. However, no tests on other platforms than Linux have been performed.
• The build process uses the following tools (the version with which the build process has been tested is included in brackets):
  • GNU Make (3.81)
  • A C++ compiler (as selected by ./configure). We use gcc 4.3.1 (20080507 prerelease).
  • lunit 0.5 for the Lua unit test cases (not required if you use PropXX without running the automatic test suite).
  • LuaDoc (3.0.1) for the automatic generation of the Lua API documentation (not required if you do not want to change this documentation).
• The graphical editor uses the tekUI widget set (not required for the core functionality of PropXX).

Installation

Building and installing PropXX

The usual

./configure
make
make check    # (optional, runs the test suite)
make install

./configure --prefix=/install/path \
  CPPFLAGS="-I/path/to/lua/include" LDFLAGS="-L/path/to/lua/lib"

The build process generated a small static library libpropxx.a which is installed to /install/path/lib.

Since PropXX is a small and lean tool, it is also a perfectly valid approach to directly include the C++ sources into the build process of your application instead of building and using the library. Please note that the library only allows that for projects with a license that is compatible with the GPL. Closed-source projects have to link to the library and may not modify the PropXX sources (unless these changes are published as Open Source in agreement with the terms of the GPL, of course).

Documentation

• User guide, which can quickly get you started with PropXX (also available as pdf)
• API-documentation of the Lua code (not required for most users but provides detailed information beyond the user guide)

Support