\f
-/* 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.
*
*/
/*
* Use these macros if it's important (for correctness)
- * that %nil MUST be considered true
+ * that #nil MUST be considered true
*/
#define scm_is_false_and_not_nil(x) (scm_is_eq ((x), SCM_BOOL_F))
#define scm_is_true_or_nil(x) (!scm_is_eq ((x), SCM_BOOL_F))
/*
- * Use these macros if %nil will never be tested,
+ * Use these macros if #nil will never be tested,
* for increased efficiency.
*/
#define scm_is_false_assume_not_nil(x) (scm_is_eq ((x), SCM_BOOL_F))
* SCM_MATCHES_BITS_IN_COMMON in tags.h for more information on
* how the following macro works.
*/
-#if SCM_ENABLE_ELISP
-# define scm_is_false_or_nil(x) \
+#define scm_is_false_or_nil(x) \
(SCM_MATCHES_BITS_IN_COMMON ((x), SCM_ELISP_NIL, SCM_BOOL_F))
-#else
-# define scm_is_false_or_nil(x) (scm_is_false_assume_not_nil (x))
-#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))
/*
*
* If SCM_ENABLE_ELISP is true, then scm_is_bool_or_nil(x)
* returns 1 if and only if x is one of the following: SCM_BOOL_F,
- * SCM_BOOL_T, SCM_ELISP_NIL, or SCM_XXX_ANOTHER_BOOLEAN_DONT_USE.
+ * SCM_BOOL_T, SCM_ELISP_NIL, or SCM_XXX_ANOTHER_BOOLEAN_DONT_USE_0.
* Otherwise, it returns 0.
*/
-#if SCM_ENABLE_ELISP
-# define scm_is_bool_or_nil(x) \
+#define scm_is_bool_or_nil(x) \
(SCM_MATCHES_BITS_IN_COMMON ((x), SCM_BOOL_T, SCM_ELISP_NIL))
-#else
-# define scm_is_bool_or_nil(x) (scm_is_bool_and_not_nil (x))
-#endif
-
#define scm_is_bool_and_not_nil(x) \
(SCM_MATCHES_BITS_IN_COMMON ((x), SCM_BOOL_F, SCM_BOOL_T))
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);
\f
+/* Older spellings for the above routines, kept around for
+ compatibility. */
+#define SCM_FALSEP(x) (scm_is_false (x))
+#define SCM_NFALSEP(x) (scm_is_true (x))
+#define SCM_BOOLP(x) (scm_is_bool (x))
+#define SCM_BOOL(x) (scm_from_bool (x))
+#define SCM_NEGATE_BOOL(f) (scm_from_bool (!(f)))
+#define SCM_BOOL_NOT(x) (scm_not (x))
+
+\f
+
/*
* The following macros efficiently implement boolean truth testing as
* expected by most lisps, which treat '() aka SCM_EOL as false.
* following: SCM_BOOL_F, SCM_ELISP_NIL, SCM_EOL or
* SCM_XXX_ANOTHER_LISP_FALSE_DONT_USE. Otherwise, it returns 0.
*/
-#if SCM_ENABLE_ELISP
-# define scm_is_lisp_false(x) \
+#define scm_is_lisp_false(x) \
(SCM_MATCHES_BITS_IN_COMMON ((x), SCM_BOOL_F, SCM_EOL))
-# define scm_is_lisp_true(x) (!scm_is_lisp_false(x))
-#endif
\f