From c79a96bae7757d2ec62776d3b2b05fffcdb3394d Mon Sep 17 00:00:00 2001
From: Justin Ethier <justin.ethier@gmail.com>
Date: Thu, 20 Aug 2015 22:14:19 -0400
Subject: [PATCH] Added letrec stub

---
 scheme/base.sld               | 13 +++++++++++++
 scheme/cyclone/transforms.sld |  4 ++--
 2 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/scheme/base.sld b/scheme/base.sld
index f57c1686..85e0e623 100644
--- a/scheme/base.sld
+++ b/scheme/base.sld
@@ -86,6 +86,7 @@
     or
     let
     let*
+    ;letrec
     begin
     case
     cond
@@ -153,6 +154,18 @@
                   `(,(rename 'let) (,(caar (cdr expr)))
                     (,(rename 'let*) ,(cdar (cdr expr)) ,@(cddr expr)))
                   (error "bad let* syntax"))))))
+;    (define-syntax letrec 
+;      (er-macro-transformer
+;        (lambda (exp rename compare)
+;          (let* ((bindings  (cadr exp)) ;(letrec->bindings exp)
+;                 (namings   (map (lambda (b) (list (car b) #f)) bindings))
+;                 (names     (map car (cadr exp))) ;(letrec->bound-vars exp)
+;                 (sets      (map (lambda (binding) 
+;                                   (cons 'set! binding))
+;                                 bindings))
+;                 (args      (map cadr (cadr exp)))) ;(letrec->args exp)
+;            `(let ,namings
+;               (begin ,@(append sets (cddr exp)))))))) ;(letrec->exp exp)
     (define-syntax begin 
       (er-macro-transformer
         (lambda (exp rename compare)
diff --git a/scheme/cyclone/transforms.sld b/scheme/cyclone/transforms.sld
index 2de16d1a..87507374 100644
--- a/scheme/cyclone/transforms.sld
+++ b/scheme/cyclone/transforms.sld
@@ -366,11 +366,11 @@
 (define (letrec->exp exp)
   (cddr exp))
 
-; letrec->exp : letrec-exp -> list[symbol]
+; letrec->bound-vars : letrec-exp -> list[symbol]
 (define (letrec->bound-vars exp)
   (map car (cadr exp)))
 
-; letrec->exp : letrec-exp -> list[exp]
+; letrec->args : letrec-exp -> list[exp]
 (define (letrec->args exp)
   (map cadr (cadr exp)))