summaryrefslogtreecommitdiff
path: root/libguile/boolean.h
diff options
context:
space:
mode:
authorAndy Wingo <wingo@pobox.com>2010-03-23 20:23:19 +0100
committerAndy Wingo <wingo@pobox.com>2010-03-30 10:31:27 +0200
commitd38b431ace4b01e5da9cb09bb6341277f2974160 (patch)
tree745db83549f083455e0ac4e96058da3e67acbba7 /libguile/boolean.h
parent655aadf4b09c40f4c7854e4325e8809fcb7cb36b (diff)
downloadguile-d38b431ace4b01e5da9cb09bb6341277f2974160.tar.gz
nil is false, whee
* libguile/boolean.h (scm_is_false): Recognize nil as false, by default. (scm_is_bool): Recognize nil as a boolean. * libguile/boolean.c (scm_not, scm_boolean, scm_to_bool, scm_is_bool): Adapt to treat nil as false. * libguile/vm-i-system.c (br-if, br-if-not): Just use scm_is_false instead of specifically mentioning nil.
Diffstat (limited to 'libguile/boolean.h')
-rw-r--r--libguile/boolean.h11
1 files changed, 6 insertions, 5 deletions
diff --git a/libguile/boolean.h b/libguile/boolean.h
index bc108f5c3..007500e10 100644
--- a/libguile/boolean.h
+++ b/libguile/boolean.h
@@ -27,7 +27,9 @@
-/* Boolean Values
+/* Boolean Values. Obviously there are #t and #f, but there is also nil to deal
+ * with. We choose to treat nil as a false boolean. All options might silently
+ * break existing code, but this one seems most responsible.
*
*/
@@ -58,8 +60,8 @@
#endif
#define scm_is_true_and_not_nil(x) (!scm_is_false_or_nil (x))
-/* XXX Should these macros treat %nil as false by default? */
-#define scm_is_false(x) (scm_is_false_and_not_nil (x))
+/* %nil is false. */
+#define scm_is_false(x) (scm_is_false_or_nil (x))
#define scm_is_true(x) (!scm_is_false (x))
/*
@@ -90,8 +92,7 @@
SCM_API int scm_is_bool (SCM);
-/* XXX Should scm_is_bool treat %nil as a boolean? */
-#define scm_is_bool(x) (scm_is_bool_and_not_nil (x))
+#define scm_is_bool(x) (scm_is_bool_or_nil (x))
#define scm_from_bool(x) ((x) ? SCM_BOOL_T : SCM_BOOL_F)
SCM_API int scm_to_bool (SCM x);