Wanted to put my article-gleaned understanding of lisp to the test + get at the essence of what shebang-style unix scripting was about.

Here is a reimplementation of "cat" in it:

    #!/usr/bin/env imp

    (def copy-out (proc (x)
      (let f (if (file? x) x (open x))
           bytes (read default-chunk f)
           (if bytes
               (seq (write bytes stdout)
                    (recur f))
               (close f)))))

    (if (nil? script-args)
        (copy-out stdin)
        (each copy-out script-args))

Running external programs is a bit more verbose than normal shell, but there is some optional reader-macro sugar on top of fork+exec, e.g. the effect of the following is that /usr/bin/say gets run with those non-string args converted to strings and a voice comes out of my speaker.

    !(say hello there)
    => ((status : 0) (pid : 2945) (in : [File]) (out : [File]) (err : [File]))