gistfile1.clj

  (defmacro new-if [pred then-clause else-clause]
    `(cond ~pred ~then-clause
           :else ~else-clause))
           
"This works, in that if I call it like so:
"

(new-if (= 2 3) (while true (print "hi"))  :bye)

"I don't get an infinite loop, but I don't understand how. I've unquoted 
 everything in the macro body, so shouldn't the normal evaluation order 
 apply? Why doesn't it evaluate then-clause when I do it this way?
"

So it turns out that cond is already doing everything I want new-if to do. I want to demonstrate the power of macros by defining 'if' with one, but I can't work out how to do it without using a pre-existing macro?

"if" is a special form with custom evaluation order. Usually people write macros in terms of "if" (or other things built on if like cond) to show how to write new syntax with delayed evaluation.

I think I'll have more luck doing it with Scheme's define-syntax.