How to create a DSL in Elisp

Question

I want to create a DSL in Elisp looking something like this:

(install
 ;; do install
 )

(uninstall
 ;; do uninstall
 )

However, since Elisp have a global namespace, this is not a good idea. And prefixing the functions like this, is so darn ugly.

(package-install
 ;; do install
 )

(package-uninstall
 ;; do uninstall
 )

So I thought as a compromise all commands could be wrapped in a commands call like this:

(commands
 (install
  ;; do install
  )

 (uninstall
  ;; do uninstall
  )

 ;; ...
 )

But since I don't want install and uninstall in the global namespace, I somehow have to in the commands macro, replace all occurrences of the commands with maybe for example the prefix names, like this:

(defmacro commands (&rest body)
  (mapcar
   (lambda (exp)
     (setcar exp (intern (concat "package-" (symbol-name (car exp)))))
     (setcdr exp (list (cons 'progn (cdr exp)))))
   body)
  `(progn ,@body))

(commands
 (install
  ;; do install
  )

 (uninstall
  ;; do uninstall
  )

 ;; ...
 )

This seems like such a hack. Plus it will not work if there are any nested commands.

Is there any good solution for this or is hack the way to go?

Thanks!

Answer 1

How about locally defining install and friends? This won't hide standard functions, but it doesn't look like that's what you're really after.

(defmacro commands (&rest body)
  `(flet ((install (&rest args) (apply 'package-install args))
          (uninstall (&rest args) (apply 'package-uninstall args)))
     ,@body))

Of course you'd want to generate that list of flet arguments automatically. You do need a list of your package's elements somewhere, possibly using (feature-symbols 'package).