From 2390d46a6323394adbafa630b54b9bd50aca9229 Mon Sep 17 00:00:00 2001
From: Jan Nieuwenhuizen <janneke@gnu.org>
Date: Mon, 19 Dec 2016 19:35:38 +0100
Subject: [PATCH] Closure is not a pair.

* module/mes/base.mes (closure_p, mes_car, mes_cdr): New function.
  (pair_p): Closure is not a pair.
* NEWS: Mention it.
* psyntax-0.mes (self-evaluating?): Add closure?.
---
 NEWS                     |  2 ++
 module/mes/base.mes      |  2 +-
 module/mes/psyntax-0.mes |  2 +-
 tests/closure.test       |  6 ++++++
 type.c                   | 20 +++++++++++++++++++-
 5 files changed, 29 insertions(+), 3 deletions(-)

diff --git a/NEWS b/NEWS
index 0495be8f..621578b3 100644
--- a/NEWS
+++ b/NEWS
@@ -22,6 +22,8 @@ block-comments are all handled by the Scheme reader later.
 *** Lambda* and define* are now supported.
 *** #;-comment is now supported.
 *** Non-nested #| |#-comment is now supported.
+** Noteworthy bug fixes
+*** Closure is not a pair.
 * Changes in 0.3 since 0.2
 ** Core
 *** Number-based rather than pointer-based cells.
diff --git a/module/mes/base.mes b/module/mes/base.mes
index 7ac4b4d9..e3510000 100644
--- a/module/mes/base.mes
+++ b/module/mes/base.mes
@@ -59,5 +59,5 @@
 (define (procedure? p)
   (cond ((builtin? p) #t)
         ((and (pair? p) (eq? (car p) 'lambda)))
-        ((and (pair? p) (eq? (car p) '*closure*)))
+        ((closure? p) #t)
         (#t #f)))
diff --git a/module/mes/psyntax-0.mes b/module/mes/psyntax-0.mes
index 04bb1d6d..350dc6c9 100644
--- a/module/mes/psyntax-0.mes
+++ b/module/mes/psyntax-0.mes
@@ -33,7 +33,7 @@
 
 (define annotation? (lambda (x) #f))
 (define (self-evaluating? x)
-  (or (boolean? x) (number? x) (string? x) (char? x) (null? x)))
+  (or (boolean? x) (number? x) (string? x) (char? x) (null? x) (closure? x)))
 
 (define (void) (if #f #f))
 
diff --git a/tests/closure.test b/tests/closure.test
index 494daca8..80987192 100755
--- a/tests/closure.test
+++ b/tests/closure.test
@@ -95,4 +95,10 @@ exit $?
     "noexpand")
    (pass-if "closure 9" (sc-expand))))
 
+(pass-if "closure is procedure"
+             (procedure? (lambda () #t)))
+
+(pass-if-not "closure is not a pair"
+             (pair? (lambda () #t)))
+
 (result 'report)
diff --git a/type.c b/type.c
index ca28387a..c8d5933b 100644
--- a/type.c
+++ b/type.c
@@ -26,6 +26,24 @@ char_p (SCM x)
   return TYPE (x) == CHAR ? cell_t : cell_f;
 }
 
+SCM
+closure_p (SCM x)
+{
+  return (TYPE (x) == PAIR && CAR (x) == cell_closure) ? cell_t : cell_f;
+}
+
+SCM
+mes_car (SCM x)
+{
+  return CAR (x);
+}
+
+SCM
+mes_cdr (SCM x)
+{
+  return CDR (x);
+}
+
 SCM
 keyword_p (SCM x)
 {
@@ -47,7 +65,7 @@ number_p (SCM x)
 SCM
 pair_p (SCM x)
 {
-  return TYPE (x) == PAIR ? cell_t : cell_f;
+  return (TYPE (x) == PAIR && CAR (x) != cell_closure) ? cell_t : cell_f;
 }
 
 SCM