From 08b1a52af2a91c7828a0ed723609905cd306c866 Mon Sep 17 00:00:00 2001
From: Jan Nieuwenhuizen <janneke@gnu.org>
Date: Sat, 16 Jul 2016 07:56:50 +0200
Subject: [PATCH] syntax.mes: experiments...

---
 syntax.mes | 94 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 94 insertions(+)
 create mode 100644 syntax.mes

diff --git a/syntax.mes b/syntax.mes
new file mode 100644
index 00000000..699efb7f
--- /dev/null
+++ b/syntax.mes
@@ -0,0 +1,94 @@
+
+(display "define-syntax...")
+
+(define-macro define-syntax
+  (lambda (form expander)
+    (expander `(define-macro ,(cadr form)
+                 (let ((transformer ,(caddr form)))
+                   (lambda (form expander)
+                     (expander (transformer form
+                                            (lambda (x) x)
+                                            eq?)
+                               expander))))
+              expander)))
+
+(newline)
+
+(display "define-syntax when...")
+
+;; (define-syntax when
+;;   (syntax-rules ()
+;;     ((when condition exp ...)
+;;      (if condition
+;;          (begin exp ...)))))
+
+;; (define-macro (when cond exp . rest)
+;;   `(if ,cond
+;;        (begin ,exp . ,rest)))
+
+
+(define-macro (when clause . rest)
+  (cond
+   ((not (eq? clause #f)) (cons 'let (cons '() rest)))))
+
+(define-macro (ifwhen clause . rest)
+  (if (not (eq? clause #f)) (cons 'let (cons '() rest))))
+
+(define-macro my-when
+  (lambda (test . branch)
+    (list 'if test (cons 'begin branch))))
+
+;; (define-macro (q-when test . branch)
+;;   `(if ,test
+;;        (begin ,@branch)))
+
+;; (define-macro (when clause exp . rest)
+;;   (display "all=")
+;;   (display  (cons exp rest))
+;;   (newline)
+;;   `(if ,clause
+;;        (begin ,(cons exp rest))))
+
+;; (define-macro (when clause . rest)
+;;   (cond
+;;    ((not (eq? clause #f)) (cons 'let (cons '() rest)))))
+
+(newline)
+
+(ifwhen #t
+  (display "true")
+  (newline))
+
+(ifwhen #f
+  (display "false")
+  (newline)
+  '())
+
+(my-when #t
+  (display "my-when")
+  (newline)
+  '())
+
+
+;; (q-when #t
+;;   (display "q-when")
+;;   (newline)
+;;   '())
+
+
+(define *gensym* 0)
+(define (gensym)
+  (set! *gensym* (+ *gensym* 1))
+  (string->symbol (string-append "g" (number->string *gensym*))))
+
+(define-macro bla (gensym))
+
+(display bla) (newline)
+(display bla) (newline)
+(display bla) (newline)
+
+(newline)
+'()
+
+;;EOF
+EOF2