Arc Forumnew | comments | leaders | submitlogin
1 point by eds 6152 days ago | link | parent

Yeah, I see the problem with that.

cchooper, did you actually ever run your version? I can't make your orginal version work.

  arc> (def-with-prefix pre foo (x) (+ 1 x))
  Error: "reference to undefined identifier: _x"
And looking at the macro expansion, I'm not at all surprised:

  arc> (macex '(def-with-prefix pre foo (x) (+ 1 x)))
  (eval (list (quote def) ; my indentation
              (read (+ (coerce pre (quote string)) "-" (coerce (quote foo) (quote string))))
              (x) (+ 1 x)))
args and body would need to be quoted for this to work properly. And then it admittedly does what it is supposed to, but it becomes even uglier.

  (mac def-with-prefix (prefix name args . body)
    `(eval (list 'def
            (read (+ (coerce ,prefix 'string)
                     "-"
                     (coerce ',name 'string)))
            ',args
            ,@(map [list 'quote _] body))))


1 point by cchooper 6152 days ago | link

Hmmm... it worked last night. I must have made a mistake when I copied it into the comment. Thanks for catching it.

Here's a slightly less clunky version:

  (mac def-with-prefix (prefix name args . body)
    `(eval (join (list 'def 
                  (sym (+ (coerce ,prefix 'string)
                          "-"
                          (coerce ',name 'string)))
                  ',args)
            ',body)))
I also tried doing it with nested quasiquotes but that just looked worse.

-----