From 1d28c3c3d63acc95e00113cf1ffe07adaa36000a Mon Sep 17 00:00:00 2001
From: Meng Zhang <zhangmeng@google.com>
Date: Tue, 20 Dec 2016 17:53:50 -0800
Subject: [PATCH 1/2] Add support for syntax-case

---
 define-library.scm | 27 ++++++++++++++-------------
 when-unless.scm    |  7 ++++---
 2 files changed, 18 insertions(+), 16 deletions(-)

diff --git a/define-library.scm b/define-library.scm
index 03cfbe9..beb8f48 100644
--- a/define-library.scm
+++ b/define-library.scm
@@ -16,6 +16,8 @@
 
 (##include "syntax.scm")
 (##include "syntaxrulesxform.scm")
+(##include "syntaxcasexform.scm")
+(##include "syntaxxform.scm")
 
 (define-runtime-syntax define-syntax
   (lambda (src)
@@ -28,6 +30,12 @@
 (define-runtime-syntax syntax-rules
   syn#syntax-rules-form-transformer)
 
+(define-runtime-syntax syntax-case
+  syn#syntax-case-form-transformer)
+
+(define-runtime-syntax syntax
+  (lambda (src) (syn#syntax-form-transformer src '())))
+
 ;;;============================================================================
 
 (define (keep keep? lst)
@@ -582,29 +590,25 @@
                           (pair? (cdr expr))
                           (symbol? (##source-strip (cadr expr)))
                           (pair? (cddr expr))
-                          (let ((x (##source-strip (caddr expr))))
-                            (and (pair? x)
-                                 (eq? (##source-strip (car x)) 'syntax-rules)))
                           (null? (cdddr expr))))
                 (done)
                 (let ((id (##source-strip (cadr expr)))
-                      (crules (syn#syntax-rules->crules (caddr expr))))
+                      (form (caddr expr)))
 
-                  (define (generate-local-macro-def id crules expr-src)
+                  (define (generate-local-macro-def id form expr-src)
                     (let ((locat (##source-locat expr-src)))
                       (##make-source
                        `(##define-syntax ,id
-                          (##lambda (##src)
-                            (syn#apply-rules ',crules ##src)))
+                         ,form)
                        locat)))
 
                   ;; replace original define-syntax by local macro def
                   ;; to avoid having to load syntax-rules implementation
                   (set-car! expr-srcs
-                            (generate-local-macro-def id crules expr-src))
+                            (generate-local-macro-def id form expr-src))
 
                   (loop (cdr expr-srcs)
-                        (cons (cons id crules)
+                        (cons (cons id form)
                               rev-macros))))))))
 
   (let ((form (##source-strip src)))
@@ -684,10 +688,7 @@
                                           (string-append
                                            (idmap-namespace idmap)
                                            (symbol->string id)))
-                                        (##lambda (src)
-                                          (syn#apply-rules
-                                           (##quote ,(cdr m))
-                                           src))))
+                                        ,(cdr m)))
                                     '())))
                             (idmap-macros idmap))))))
 
diff --git a/when-unless.scm b/when-unless.scm
index c38f650..24780ba 100644
--- a/when-unless.scm
+++ b/when-unless.scm
@@ -12,9 +12,10 @@
   (begin
 
     (define-syntax when
-      (syntax-rules ()
-        ((_ test expr expr* ...)
-         (if test (begin expr expr* ...)))))
+      (lambda (x)
+        (syntax-case x ()
+          ((_ test e e* ...)
+           #'(if test (begin e e* ...))))))
 
     (define-syntax unless
       (syntax-rules ()

From 0e676780149944887feab1a7981c88b0df71d2fe Mon Sep 17 00:00:00 2001
From: Meng Zhang <zhangmeng@google.com>
Date: Tue, 20 Dec 2016 18:30:10 -0800
Subject: [PATCH 2/2] Add macro support

---
 define-library.scm | 8 ++++++++
 test.scm           | 6 +++++-
 when-unless.scm    | 5 ++++-
 3 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/define-library.scm b/define-library.scm
index beb8f48..e7f54fb 100644
--- a/define-library.scm
+++ b/define-library.scm
@@ -36,6 +36,14 @@
 (define-runtime-syntax syntax
   (lambda (src) (syn#syntax-form-transformer src '())))
 
+(define-runtime-syntax macro
+  (lambda (src)
+    (let ((locat (##source-locat src)))
+      (##make-source
+       `(##lambda (##src)
+         (##apply (##lambda ,@(cdr (##source-strip src))) (##cdr (##source-strip ##src))))
+      locat))))
+
 ;;;============================================================================
 
 (define (keep keep? lst)
diff --git a/test.scm b/test.scm
index d702dfc..46f746b 100644
--- a/test.scm
+++ b/test.scm
@@ -15,6 +15,7 @@
   (begin
 
     (define skip-test #f)
+    (define z 10)
 
     (unless skip-test
 
@@ -22,4 +23,7 @@
       (pp (digest-string "" 'sha-1 'hex))
 
       ;; should give "a9993e364706816aba3e25717850c26c9cd0d89d"
-      (pp (digest-string "abc" 'sha-1 'hex)))))
+      (pp (digest-string "abc" 'sha-1 'hex)))
+
+    (when z 
+      (pp (addn 5 z)))))
diff --git a/when-unless.scm b/when-unless.scm
index 24780ba..f68b20e 100644
--- a/when-unless.scm
+++ b/when-unless.scm
@@ -7,9 +7,12 @@
   (import (only (gambit)
                 if not begin)) ;; required by expansions of when and unless
 
-  (export when unless)
+  (export when unless addn)
 
   (begin
+    (define-syntax addn
+      (macro args
+             `(##+ ,(car args) ,(cadr args))))
 
     (define-syntax when
       (lambda (x)