Fresh from the 2011 GNU Hackers Meeting , Andy Wingo has written a long piece on the status of Guile Scheme , the woefully underutilized official user extension language of GNU. Wingo argues that Guile is the best choice for extension in GNU given the ability of Scheme to adapt to change over time. Presented with using e.g. Javascript instead of Scheme for its popularity: 'We should also consider the costs of using hastily designed languages. JavaScript has some crazy bad stuff, like with, var hoisting, a poor numeric model, dynamic this scoping, lack of modularity regarding binding lookup ... Finally, we have the lifespan issue. If GNU had chosen Tcl because it was popular , we would have a mass of dead code' (it should be noted that Guile does partially support Javascript syntax ). With the proliferation of Firefox extensions, Greasemonkey, etc. it is clear there is a large set of power users who want to modify the programs they use without spending years becoming skilled programmers. Perhaps after Emacs has been ported to Guile the philosophy of user extensibility will spread to other parts of the GNU system.