Package EXT does not exist

I am currently working through the Land of Lisp examples and have run into a compile exception: package EXT does not exist from this line I suspect: (ext:shell (concatenate 'string "dot -Tpng -O" fname))

I am running my repl inside emacs with slime and am unsure as to how to remedy this after some googling of the error.

Any help would be much appreciated.


  • It was in fact that SBCL was set as the default lisp program in emacs.

    By replacing:

    (setq inferior-lisp-program "/usr/bin/sbcl")


    (setq inferior-lisp-program "/usr/bin/clisp")

    in my emacs configuration file fixed the issue. (On a Unix system at least)