Thank you for taking the time to read about &SCons;. &SCons; is a next-generation software construction tool, or make tool--that is, a software utility for building software (or other files) and keeping built software up-to-date whenever the underlying input files change. The most distinctive thing about &SCons; is that its configuration files are actually scripts, written in the &Python; programming language. This is in contrast to most alternative build tools, which typically invent a new language to configure the build. &SCons; still has a learning curve, of course, because you have to know what functions to call to set up your build properly, but the underlying syntax used should be familiar to anyone who has ever looked at a Python script. Paradoxically, using Python as the configuration file format makes &SCons; easier for non-programmers to learn than the cryptic languages of other build tools, which are usally invented by programmers for other programmers. This is in no small part to the consistency and readability that are built in to Python. It just so happens that making a real, live scripting language the basis for the configuration files makes it a snap for more accomplished programmers to do more complicated things with builds, as necessary.

&SCons; is a response to a perennial problem: building software is harder than it should be. In a nutshell: the old, reliable model of the venerable and ubiquitous &Make; program has had a hard time keeping up with how complicated building software has become. The fact that &Make; has kept up as well as it has is impressive, and a testament to how the simplicity. But anyone who has wrestled with &Automake; and &Autoconf; to try to guarantee that a bit of software will build correctly on multiple platforms can tell you that it takes a lot of work to get right.

There are a few overriding principles we try to live up to in designing and implementing &SCons: Correctness First and foremost, by default, &SCons; guarantees a correct build even if it means sacrificing performance a little. We strive to guarantee the build is correct regardless of how the software being built is structured, how it may have been written, or how unusual the tools are that build it. Performance Given that the build is correct, we try to make &SCons; build software as quickly as possible. In particular, wherever we may have needed to slow down the default &SCons; behavior to guarantee a correct build, we also try to make it easy to speed up &SCons; through optimization options that let you trade off guaranteed correctness for speed. Convenience &SCons; tries to do as much for you out of the box as reasonable, including detecting the right tools on your system and using them correctly to build the software. In a nutshell, we try hard to make &SCons; just "do the right thing" and build software correctly, with a minimum of hassles.

&SCons; originated with a design that was submitted to the Software Carpentry design competition in 2000. &SCons; is the direct descendant of a Perl utility called &Cons;. &Cons; in turn based some of its ideas on &Jam;, a build tool from Perforce Systems. XXX

&SCons; would not exist without a lot of help from a lot of people, many of whom may not even be aware that they helped or served as inspiration. So in no particular order, and at the risk of leaving out someone: First and foremost, &SCons; owes a tremendous debt to Bob Sidebotham, the original author of the classic Perl-based &Cons; tool which Bob first released to the world back around 1996. Bob's work on Cons classic provided the underlying architecture and model of specifying a build configuration using a real scripting language. My real-world experience working on Cons informed many of the design decisions in SCons, including the improved parallel build support, making Builder objects easily definable by users, and separating the build engine from the wrapping interface. Greg Wilson was instrumental in getting &SCons; started as a real project when he initiated the Software Carpentry design competition in February 2000. Without that nudge, marrying the advantages of the Cons classic architecture with the readability of Python might have just stayed no more than a nice idea. The entire &SCons; team have been absolutely wonderful to work with, and &SCons; would be nowhere near as useful a tool without the energy, enthusiasm and time people have contributed over the past few years. The "core team" of Chad Austin, Anthony Roach, Charles Crain, Steve Leblanc, Greg Spencer and Christoph Wiedemann have been great about reviewing my (and other) changes and catching problems before they get in the code base. Of particular technical note: Anthony's outstanding and innovative work on the tasking engine has given &SCons; a vastly superior parallel build model; Charles has been the master of the crucial Node infrastructure; Christoph's work on the Configure infrastructure has added crucial Autoconf-like functionality; and Greg has provided excellent support for Microsoft Visual Studio. Special thanks to David Snopek for contributing his underlying "Autocons" code that formed the basis of Christoph's work with the Configure functionality. David was extremely generous in making this code available to &SCons;, given that he initially released it under the GPL and &SCons; is released under a less-restrictive MIT-style license. &SCons; has received contributions from many other people, of course: Matt Balvin (extending long command-line support on Win32), Allen Bierbaum (extensions and fixes to Options), Steve Christensen (help text sorting and function action signature fixes), Michael Cook (avoiding losing signal bits from executed commands), Derrick 'dman' Hudson (), Alex Jacques (work on the Win32 scons.bat file), Stephen Kennedy (performance enhancements), Lachlan O'Dea (SharedObject() support for masm and normalized paths for the WhereIs() function), Damyan Pepper (keeping output like Make), Jeff Petkau (significant fixes for CacheDir and other areas), Stefan Reichor (Ghostscript support), Zed Shaw (Append() and Replace() environment methods), Terrel Shumway (build and test fixes, as well as the SCons Wiki), sam th (dynamic checks for utilities) and Moshe Zadke (Debian packaging). Thanks to Peter Miller for his splendid change management system, &Aegis;, which has provided the &SCons; project with a robust development methodology from day one, and which showed me how you could integrate incremental regression tests into a practical development cycle (years before eXtreme Programming arrived on the scene). And last, thanks to Guido van Rossum for his elegant scripting language, which is the basis not only for the &SCons; implementation, but for the interface itself.

The best way to contact people involved with SCons, including the author, is through the SCons mailing lists. If you want to ask general questions about how to use &SCons; send email to &scons-users;. If you want to contact the &SCons; development community directly, send email to &scons-devel;. If you want to receive announcements about &SCons, join the low-volume &scons-announce; mailing list.