2.2 History of Guile and its motivations

A few separate threads of events led to the development of Guile.

In the fall of 1994, Richard Stallman, director of the GNU project, posted an article with the subject "Why you should not use Tcl", in which he argued that Tcl is inadequate as an extension language. This generated a flurry of flames (available in the hypermail archive (http://www.vanderburg.org/Tcl/war/) The Tcl War).

The result was that Stallman then proposed his design for the GNU Extension Language, first called GEL and then renamed Guile. The discussion triggered by that article is also available in a hypermail archive, http://www.vanderburg.org/Tcl/war2/.

One interesting feature of this GNU Extension Language plan was that users should have a choice of languages to use in extending their program. The basic language would be a slightly modified Scheme, and translators would be written to convert other languages (like Tcl, Python, Perl, C-like languages …) into Scheme.

Tom Lord started working on this project immediately, taking Aubrey Jaffer's small and portable implementation of Scheme, SCM, and making it into an embeddable interpreter: callable from C and allowing new Scheme procedures to be written in C.

In the spring of 1995, the guile-ii snapshot was released. This made it possible to start writing code in C and Scheme using the guile facilities.

The guile-iii snapshot was released the summer of 1995, and it had fixed enough problems so that the access to Scheme data structures from C was almost complete.

After this, Cygnus Support added many features to Guile and finished implementing others, so that Guile acquired thread support, a regular expression matcher, a Tk interface, an interface to the SGI OpenGL graphics system, an applet formalism, and some other packages. This was all in the Cygnus Guile r0.3 and r0.4 releases.

Meanwhile, Tom Lord left the project after having produced a divergent version of Guile: 1.0b2. The Free Software Foundation hired Jim Blandy to coordinate Guile development. The FSF released its first version of Guile in January 1997. In the future, many of the Cygnus packages will be re-integrated into Guile.