cond.lisp

; the let macro
(set macros "let" (fn (tree)
  (if (== (len tree) 0)
    (err "let takes at least one arg")
    (let
      (expr (last tree))
      (body (map (init tree) (fn (tree)
        (cons (quote "def") tree))))
      (form (push (cons (quote "do") body) expr))
      (compileExpr form body)))))

; the cond macro
(set macros "cond" (fn (tree)
  ; TODO when I get the >= operator in here, use that
  ; also mod
  (if (== (len tree) 0)
    (err "cond takes at least two args")
    (let
      (lt (last tree))
      (rest (slice tree 0 (- (len tree) 2)))
      (grouped (group2 rest))
      (form (foldR grouped (fn (acc con)
        (list (quote "if") (head con) (at con 1) acc)) lt))
      (compileExpr form)))))