From 5b8f47af43b6a170d5c5f4059a1ea9d07dcb5c11 Mon Sep 17 00:00:00 2001
From: Justin Ethier <justin.ethier@gmail.com>
Date: Tue, 21 Nov 2017 19:07:52 -0500
Subject: [PATCH] WIP for let-syntax

---
 scheme/cyclone/transforms.sld | 23 +++++++++++++++++++++++
 tests/let-syntax.scm          | 22 +++++++++++-----------
 2 files changed, 34 insertions(+), 11 deletions(-)

diff --git a/scheme/cyclone/transforms.sld b/scheme/cyclone/transforms.sld
index bb6cbd60..1ede1845 100644
--- a/scheme/cyclone/transforms.sld
+++ b/scheme/cyclone/transforms.sld
@@ -511,6 +511,12 @@
 
 ;TODO: modify this whole section to use macros:get-env instead of *defined-macros*. macro:get-env becomes the mac-env. any new scopes need to extend that env, and an env parameter needs to be added to (expand). any macros defined with define-syntax use that env as their mac-env (how to store that)?
 ; expand : exp -> exp
+
+;; TODO: need a local version of each expand that receives a local env built by
+;;       let-syntax forms
+;;(define (expand exp env rename-env local-env)
+;;(define (_expand exp env rename-env)
+
 (define (expand exp env rename-env)
   (define (log e)
     (display  
@@ -578,6 +584,23 @@
           ;; of the macros are defined. may need to make a special pass
           ;; to do loading or expansion of macro bodies
           `(define ,name ,(expand body env rename-env)))))))
+    ((let-syntax? exp)
+     (let* ((body (cddr exp))
+            (bindings (cadr exp))
+            (bindings-as-macros
+              (map 
+                (lambda (b)
+                  (let ((name (car b))
+                        (binding (cadr b)))
+                    (cons name (if (tagged-list? 'syntax-rules binding)
+                                   (expand binding env rename-env)
+                                   binding)))) 
+                bindings))
+            ; TODO: (new-local-macro-env (append bindings-as-macros local-env))
+           )
+(trace:error `(let-syntax ,bindings-as-macros))
+       (expand body env rename-env) ;; TODO: new-local-macro-env 
+       ))
     ((app? exp)
      (cond
        ((symbol? (car exp))
diff --git a/tests/let-syntax.scm b/tests/let-syntax.scm
index 69af2d17..a47135cd 100644
--- a/tests/let-syntax.scm
+++ b/tests/let-syntax.scm
@@ -9,17 +9,17 @@
 ;; (given-that if (set! if 'now))
 ;; if)) ;; => now
 
-;;(let ((x 'outer))
-;;  (let-syntax ((m (syntax-rules () ((m) x))))
-;;    (let ((x 'inner))
-;;      (m)))) ;; Should be outer
-
-(write 
 (let ((x 'outer))
-  (define-syntax m ;; Testing this out, but let-syntax needs to work, too
-   (syntax-rules () ((m) x)))
+  (let-syntax ((m (syntax-rules () ((m) x))))
     (let ((x 'inner))
-      (m))) ;; Should be outer
-      )
+      (m)))) ;; Should be outer
 
-(write (m)) ;; Should be an error, of course
+;(write 
+;(let ((x 'outer))
+;  (define-syntax m ;; Testing this out, but let-syntax needs to work, too
+;   (syntax-rules () ((m) x)))
+;    (let ((x 'inner))
+;      (m))) ;; Should be outer
+;      )
+;
+;(write (m)) ;; Should be an error, of course