* [PATCH] %nil-handling optimization and fixes v1
@ 2009-07-09 16:11 Mark H Weaver
2009-07-23 21:38 ` Andy Wingo
` (2 more replies)
0 siblings, 3 replies; 11+ messages in thread
From: Mark H Weaver @ 2009-07-09 16:11 UTC (permalink / raw)
To: guile-devel
[-- Attachment #1: Type: text/plain, Size: 3289 bytes --]
Attached are patches to optimize %nil handling, along with some fixes
to %nil-handling bugs, as I outlined in my recent posts.
Four patches are attached. The first.patch is the most important, and
is a prerequisite for the others. In brief it does the following:
* Renumbers the IFLAG constants.
* Adds several macros related to boolean type tests, null tests, and
boolean-truth testing (including lisp-style boolean-truth tests).
* Adds compile-time checks to verify the necessary IFLAG numbering
properties needed for the checks to work properly.
* Changes some existing code to use the new optimized macros, without
changing the semantics of the code at all (except that scm_is_bool
is changed from a function to a macro).
I added the following macros, whose names explicitly state how %nil
should be handled. See the comments in the patch for more information
about these.
scm_is_false_assume_not_lisp_nil scm_is_true_assume_not_lisp_nil
scm_is_false_and_not_lisp_nil scm_is_true_or_lisp_nil
scm_is_false_or_lisp_nil scm_is_true_and_not_lisp_nil
scm_is_lisp_false scm_is_lisp_true
scm_is_null_assume_not_lisp_nil
scm_is_null_and_not_lisp_nil
scm_is_null_or_lisp_nil
scm_is_bool_and_not_lisp_nil
scm_is_bool_or_lisp_nil
The following already-existing macros are defined as aliases, such
that their semantics is unchanged (although scm_is_bool used to be a
function and is now a macro).
scm_is_null --> scm_is_null_and_not_lisp_nil
scm_is_false --> scm_is_false_and_not_lisp_nil
scm_is_true --> scm_is_true_or_lisp_nil
scm_is_bool --> scm_is_bool_and_not_lisp_nil
(I still believe that these should be changed to versions that handle
%nil properly, but await approval on that point, so these patches do
not make those changes)
Also, if the preprocessor macro SCM_ENABLE_ELISP is not true (this
macro already existed and was used in lang.h), all overheads
associated with %nil handling are eliminated from the above macros.
vm-fixes.patch changes semantics, by fixing %nil handling in the
following instructions: br-if, br-if-not, br-if-null, br-if-not-null,
not, not-not, null?, and not-null?
srfi-1-fixes.patch changes semantics, by fixing %nil handling in
several functions. Note that this patch (and several other large
forthcoming patches) will be unnecessary if the scm_is_false,
scm_is_true, and scm_is_null macros are changed to handle %nil as I
proposed.
non-essential.patch is the last and least important. It doesn't
change any functionality or implementation. It changes two
occurrences of scm_is_bool and scm_is_null, in which %nil must *not*
be treated as a boolean or null, to use newly-added equivalent macros
which are explicit about how nil should be handled. These changes
will be needed if scm_is_null is changed as I proposed. It also adds
a few comments related to %nil handling.
I've run "make check" on recent git master (c4b681fd) with these
patches applied, and everything seems to work.
I haven't yet run any benchmarks, because I'm not sure how to best do
that. I doubt the changes will make any noticeable difference except
possibly in C code which does a lot of tests which include %nil.
Comments and suggestions solicited.
Best,
Mark
[-- Attachment #2: first.patch --]
[-- Type: text/x-diff, Size: 15945 bytes --]
diff --git a/libguile/tags.h b/libguile/tags.h
index 3294533..25aea09 100644
--- a/libguile/tags.h
+++ b/libguile/tags.h
@@ -516,12 +516,47 @@ enum scm_tc8_tags
#define SCM_MAKIFLAG(n) SCM_MAKE_ITAG8 ((n), scm_tc8_flag)
#define SCM_IFLAGNUM(n) (SCM_ITAG8_DATA (n))
+/*
+ * IMPORTANT NOTE regarding IFLAG numbering!!!
+ *
+ * Several macros depend upon careful IFLAG numbering of SCM_BOOL_F,
+ * SCM_BOOL_T, SCM_ELISP_NIL, SCM_EOL, and the two SCM_XXX_*_DONT_USE
+ * constants. In particular:
+ *
+ * - SCM_BOOL_F and SCM_BOOL_T must differ in exactly one bit position.
+ * (used to implement scm_is_bool_and_not_lisp_nil, aka scm_is_bool)
+ *
+ * - SCM_ELISP_NIL and SCM_BOOL_F must differ in exactly one bit position.
+ * (used to implement scm_is_false_or_lisp_nil and
+ * scm_is_true_and_not_lisp_nil)
+ *
+ * - SCM_ELISP_NIL and SCM_EOL must differ in exactly one bit position.
+ * (used to implement scm_is_null_or_lisp_nil)
+ *
+ * - SCM_ELISP_NIL, SCM_BOOL_F, SCM_EOL, SCM_XXX_ANOTHER_LISP_FALSE_DONT_USE
+ * must all be equal except for two bit positions.
+ * (used to implement scm_is_lisp_false)
+ *
+ * - SCM_ELISP_NIL, SCM_BOOL_F, SCM_BOOL_T, SCM_XXX_ANOTHER_BOOLEAN_DONT_USE
+ * must all be equal except for two bit positions.
+ * (used to implement scm_is_bool_or_lisp_nil)
+ *
+ * These properties allow the aforementioned macros to be implemented
+ * by bitwise ANDing with a mask and then comparing with a constant,
+ * using as a common basis the macro SCM_MATCHES_BITS_IN_COMMON,
+ * defined below. The properties are checked at compile-time using
+ * `verify' macros near the top of boolean.c and pairs.c.
+ */
#define SCM_BOOL_F SCM_MAKIFLAG (0)
-#define SCM_BOOL_T SCM_MAKIFLAG (1)
-#define SCM_UNDEFINED SCM_MAKIFLAG (2)
-#define SCM_EOF_VAL SCM_MAKIFLAG (3)
-#define SCM_EOL SCM_MAKIFLAG (4)
-#define SCM_UNSPECIFIED SCM_MAKIFLAG (5)
+#define SCM_ELISP_NIL SCM_MAKIFLAG (1)
+#define SCM_XXX_ANOTHER_LISP_FALSE_DONT_USE SCM_MAKIFLAG (2)
+#define SCM_EOL SCM_MAKIFLAG (3)
+#define SCM_BOOL_T SCM_MAKIFLAG (4)
+#define SCM_XXX_ANOTHER_BOOLEAN_DONT_USE SCM_MAKIFLAG (5)
+
+#define SCM_UNSPECIFIED SCM_MAKIFLAG (6)
+#define SCM_UNDEFINED SCM_MAKIFLAG (7)
+#define SCM_EOF_VAL SCM_MAKIFLAG (8)
/* When a variable is unbound this is marked by the SCM_UNDEFINED
* value. The following is an unbound value which can be handled on
@@ -531,14 +566,50 @@ enum scm_tc8_tags
* the code which handles this value in C so that SCM_UNDEFINED can be
* used instead. It is not ideal to let this kind of unique and
* strange values loose on the Scheme level. */
-#define SCM_UNBOUND SCM_MAKIFLAG (6)
-
-/* The Elisp nil value. */
-#define SCM_ELISP_NIL SCM_MAKIFLAG (7)
-
+#define SCM_UNBOUND SCM_MAKIFLAG (9)
#define SCM_UNBNDP(x) (scm_is_eq ((x), SCM_UNDEFINED))
+/*
+ * SCM_MATCHES_BITS_IN_COMMON(x,a,b) returns 1 if and only if x
+ * matches both a and b in every bit position where a and b are equal;
+ * otherwise it returns 0. Bit positions where a and b differ are
+ * ignored.
+ *
+ * This is used to efficiently compare against two values which differ
+ * in exactly one bit position, or against four values which differ in
+ * exactly two bit positions. It is the basis for the following
+ * macros:
+ *
+ * scm_is_null_or_lisp_nil,
+ * scm_is_false_or_lisp_nil,
+ * scm_is_true_and_not_lisp_nil,
+ * scm_is_lisp_false,
+ * scm_is_lisp_true,
+ * scm_is_bool_and_not_lisp_nil (aka scm_is_bool)
+ * scm_is_bool_or_lisp_nil.
+ */
+#define SCM_MATCHES_BITS_IN_COMMON(x,a,b) \
+ ((SCM_UNPACK(x) & ~(SCM_UNPACK(a) ^ SCM_UNPACK(b))) == \
+ (SCM_UNPACK(a) & SCM_UNPACK(b)))
+
+/*
+ * These macros are used for compile-time verification that the
+ * constants have the properties needed for the above macro to work
+ * properly.
+ */
+#define SCM_WITH_LEAST_SIGNIFICANT_1_BIT_CLEARED(x) ((x) & ((x)-1))
+#define SCM_HAS_EXACTLY_ONE_BIT_SET(x) \
+ ((x) != 0 && SCM_WITH_LEAST_SIGNIFICANT_1_BIT_CLEARED (x) == 0)
+#define SCM_HAS_EXACTLY_TWO_BITS_SET(x) \
+ (SCM_HAS_EXACTLY_ONE_BIT_SET (SCM_WITH_LEAST_SIGNIFICANT_1_BIT_CLEARED (x)))
+
+#define SCM_VALUES_DIFFER_IN_EXACTLY_ONE_BIT_POSITION(a,b) \
+ (SCM_HAS_EXACTLY_ONE_BIT_SET (SCM_UNPACK(a) ^ SCM_UNPACK(b)))
+#define SCM_VALUES_DIFFER_IN_EXACTLY_TWO_BIT_POSITIONS(a,b,c,d) \
+ (SCM_HAS_EXACTLY_TWO_BITS_SET ((SCM_UNPACK(a) ^ SCM_UNPACK(b)) | \
+ (SCM_UNPACK(b) ^ SCM_UNPACK(c)) | \
+ (SCM_UNPACK(c) ^ SCM_UNPACK(d))))
\f
/* Evaluator byte codes ('immediate symbols'). These constants are used only
diff --git a/libguile/print.c b/libguile/print.c
index 6c44d59..fd65bf9 100644
--- a/libguile/print.c
+++ b/libguile/print.c
@@ -61,18 +61,17 @@
static const char *iflagnames[] =
{
"#f",
+ "#nil", /* Elisp nil value. Should print from elisp as symbol `nil'. */
+ "#<XXX_ANOTHER_LISP_FALSE_DONT_USE__SHOULD_NOT_EXIST!!>",
+ "()",
"#t",
+ "#<XXX_ANOTHER_BOOLEAN_DONT_USE__SHOULD_NOT_EXIST!!>",
+ "#<unspecified>",
"#<undefined>",
"#<eof>",
- "()",
- "#<unspecified>",
/* Unbound slot marker for GOOPS. For internal use in GOOPS only. */
"#<unbound>",
-
- /* Elisp nil value. This is its Scheme name; whenever it's printed in
- * Elisp, it should appear as the symbol `nil'. */
- "#nil"
};
SCM_SYMBOL (sym_reader, "reader");
diff --git a/libguile/boolean.h b/libguile/boolean.h
index 5a83797..2c480c0 100644
--- a/libguile/boolean.h
+++ b/libguile/boolean.h
@@ -31,16 +31,97 @@
*
*/
+/*
+ * Use these macros if it's important (for correctness)
+ * that %nil MUST be considered true
+ */
+#define scm_is_false_and_not_lisp_nil(x) (scm_is_eq ((x), SCM_BOOL_F))
+#define scm_is_true_or_lisp_nil(x) (!scm_is_eq ((x), SCM_BOOL_F))
+
+/*
+ * Use these macros if %nil will never be tested,
+ * for increased efficiency.
+ */
+#define scm_is_false_assume_not_lisp_nil(x) (scm_is_eq ((x), SCM_BOOL_F))
+#define scm_is_true_assume_not_lisp_nil(x) (!scm_is_eq ((x), SCM_BOOL_F))
+
+/*
+ * See the comments preceeding the definitions of SCM_BOOL_F and
+ * 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_lisp_nil(x) \
+ (SCM_MATCHES_BITS_IN_COMMON ((x), SCM_ELISP_NIL, SCM_BOOL_F))
+#else
+# define scm_is_false_or_lisp_nil(x) (scm_is_false_assume_not_lisp_nil (x))
+#endif
+#define scm_is_true_and_not_lisp_nil(x) (!scm_is_false_or_lisp_nil (x))
-#define scm_is_false(x) scm_is_eq ((x), SCM_BOOL_F)
-#define scm_is_true(x) !scm_is_false (x)
+/* XXX Should these macros treat %nil as false by default? */
+#define scm_is_false(x) (scm_is_false_and_not_lisp_nil (x))
+#define scm_is_true(x) (!scm_is_false (x))
+
+/*
+ * Since we know SCM_BOOL_F and SCM_BOOL_T differ by exactly one bit,
+ * and that SCM_BOOL_F and SCM_ELISP_NIL differ by exactly one bit,
+ * and that they of course can't be the same bit (or else SCM_BOOL_T
+ * and SCM_ELISP_NIL be would equal), it follows that SCM_BOOL_T and
+ * SCM_ELISP_NIL differ by exactly two bits, and these are the bits
+ * which will be ignored by SCM_MATCHES_BITS_IN_COMMON below.
+ *
+ * See the comments preceeding the definitions of SCM_BOOL_F and
+ * SCM_MATCHES_BITS_IN_COMMON in tags.h for more information.
+ *
+ * If SCM_ENABLE_ELISP is true, then scm_is_bool_or_lisp_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.
+ * Otherwise, it returns 0.
+ */
+#if SCM_ENABLE_ELISP
+# define scm_is_bool_or_lisp_nil(x) \
+ (SCM_MATCHES_BITS_IN_COMMON ((x), SCM_BOOL_T, SCM_ELISP_NIL))
+#else
+# define scm_is_bool_or_lisp_nil(x) (scm_is_bool_and_not_lisp_nil (x))
+#endif
+
+#define scm_is_bool_and_not_lisp_nil(x) \
+ (SCM_MATCHES_BITS_IN_COMMON ((x), SCM_BOOL_F, SCM_BOOL_T))
+
+/* XXX Should scm_is_bool treat %nil as a boolean? */
+#define scm_is_bool(x) (scm_is_bool_and_not_lisp_nil (x))
-SCM_API int scm_is_bool (SCM x);
#define scm_from_bool(x) ((x) ? SCM_BOOL_T : SCM_BOOL_F)
SCM_API int scm_to_bool (SCM x);
\f
+/*
+ * The following macros efficiently implement boolean truth testing as
+ * expected by most lisps, which treat '() aka SCM_EOL as false.
+ *
+ * Since we know SCM_ELISP_NIL and SCM_BOOL_F differ by exactly one
+ * bit, and that SCM_ELISP_NIL and SCM_EOL differ by exactly one bit,
+ * and that they of course can't be the same bit (or else SCM_BOOL_F
+ * and SCM_EOL be would equal), it follows that SCM_BOOL_F and SCM_EOL
+ * differ by exactly two bits, and these are the bits which will be
+ * ignored by SCM_MATCHES_BITS_IN_COMMON below.
+ *
+ * See the comments preceeding the definitions of SCM_BOOL_F and
+ * SCM_MATCHES_BITS_IN_COMMON in tags.h for more information.
+ *
+ * scm_is_lisp_false(x) returns 1 if and only if x is one of the
+ * 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) \
+ (SCM_MATCHES_BITS_IN_COMMON ((x), SCM_BOOL_F, SCM_EOL))
+# define scm_is_lisp_true(x) (!scm_is_lisp_false(x))
+#endif
+
+\f
+
SCM_API SCM scm_not (SCM x);
SCM_API SCM scm_boolean_p (SCM obj);
diff --git a/libguile/boolean.c b/libguile/boolean.c
index d79bf79..9a4f896 100644
--- a/libguile/boolean.c
+++ b/libguile/boolean.c
@@ -29,15 +29,37 @@
#include "libguile/lang.h"
#include "libguile/tags.h"
+#include "verify.h"
+
\f
+/*
+ * These compile-time tests verify the properties needed for the
+ * efficient test macros defined in boolean.h, which are defined in
+ * terms of the SCM_MATCHES_BITS_IN_COMMON macro.
+ *
+ * See the comments preceeding the definitions of SCM_BOOL_F and
+ * SCM_MATCHES_BITS_IN_COMMON in tags.h for more information.
+ */
+verify (SCM_VALUES_DIFFER_IN_EXACTLY_ONE_BIT_POSITION \
+ (SCM_BOOL_F, SCM_BOOL_T));
+verify (SCM_VALUES_DIFFER_IN_EXACTLY_ONE_BIT_POSITION \
+ (SCM_ELISP_NIL, SCM_BOOL_F));
+verify (SCM_VALUES_DIFFER_IN_EXACTLY_ONE_BIT_POSITION \
+ (SCM_ELISP_NIL, SCM_EOL));
+verify (SCM_VALUES_DIFFER_IN_EXACTLY_TWO_BIT_POSITIONS \
+ (SCM_ELISP_NIL, SCM_BOOL_F, SCM_BOOL_T, \
+ SCM_XXX_ANOTHER_BOOLEAN_DONT_USE));
+verify (SCM_VALUES_DIFFER_IN_EXACTLY_TWO_BIT_POSITIONS \
+ (SCM_ELISP_NIL, SCM_BOOL_F, SCM_EOL, \
+ SCM_XXX_ANOTHER_LISP_FALSE_DONT_USE));
SCM_DEFINE (scm_not, "not", 1, 0, 0,
(SCM x),
"Return @code{#t} iff @var{x} is @code{#f}, else return @code{#f}.")
#define FUNC_NAME s_scm_not
{
- return scm_from_bool (scm_is_false (x) || SCM_NILP (x));
+ return scm_from_bool (scm_is_false_or_lisp_nil (x));
}
#undef FUNC_NAME
@@ -47,19 +69,14 @@ SCM_DEFINE (scm_boolean_p, "boolean?", 1, 0, 0,
"Return @code{#t} iff @var{obj} is either @code{#t} or @code{#f}.")
#define FUNC_NAME s_scm_boolean_p
{
- return scm_from_bool (scm_is_bool (obj) || SCM_NILP (obj));
+ return scm_from_bool (scm_is_bool_or_lisp_nil (obj));
}
#undef FUNC_NAME
int
-scm_is_bool (SCM x)
-{
- return scm_is_eq (x, SCM_BOOL_F) || scm_is_eq (x, SCM_BOOL_T);
-}
-
-int
scm_to_bool (SCM x)
{
+ /* XXX Should this first test use scm_is_false_or_lisp_nil instead? */
if (scm_is_eq (x, SCM_BOOL_F))
return 0;
else if (scm_is_eq (x, SCM_BOOL_T))
diff --git a/libguile/pairs.h b/libguile/pairs.h
index a6d44d2..9c75709 100644
--- a/libguile/pairs.h
+++ b/libguile/pairs.h
@@ -34,7 +34,32 @@
# define SCM_VALIDATE_PAIR(cell, expr) (expr)
#endif
-#define scm_is_null(x) (scm_is_eq ((x), SCM_EOL))
+/*
+ * Use scm_is_null_and_not_lisp_nil if it's important (for correctness)
+ * that %nil must NOT be considered null.
+ */
+#define scm_is_null_and_not_lisp_nil(x) (scm_is_eq ((x), SCM_EOL))
+
+/*
+ * Use scm_is_null_assume_not_lisp_nil if %nil will never be tested,
+ * for increased efficiency.
+ */
+#define scm_is_null_assume_not_lisp_nil(x) (scm_is_eq ((x), SCM_EOL))
+
+/*
+ * See the comments preceeding the definitions of SCM_BOOL_F and
+ * SCM_MATCHES_BITS_IN_COMMON in tags.h for more information on
+ * how the following macro works.
+ */
+#if SCM_ENABLE_ELISP
+# define scm_is_null_or_lisp_nil(x) \
+ (SCM_MATCHES_BITS_IN_COMMON ((x), SCM_ELISP_NIL, SCM_EOL))
+#else
+# define scm_is_null_or_lisp_nil(x) (scm_is_null_assume_not_lisp_nil (x))
+#endif
+
+/* XXX Should scm_is_null treat %nil as null by default? */
+#define scm_is_null(x) (scm_is_null_and_not_lisp_nil(x))
#define SCM_CAR(x) (SCM_VALIDATE_PAIR (x, SCM_CELL_OBJECT_0 (x)))
#define SCM_CDR(x) (SCM_VALIDATE_PAIR (x, SCM_CELL_OBJECT_1 (x)))
diff --git a/libguile/pairs.c b/libguile/pairs.c
index aaaeb11..49eef82 100644
--- a/libguile/pairs.c
+++ b/libguile/pairs.c
@@ -27,11 +27,25 @@
#include "libguile/pairs.h"
+#include "verify.h"
+
\f
/* {Pairs}
*/
+/*
+ * This compile-time test verifies the properties needed for the
+ * efficient test macro scm_is_null_or_lisp_nil defined in pairs.h,
+ * which is defined in terms of the SCM_MATCHES_BITS_IN_COMMON macro.
+ *
+ * See the comments preceeding the definitions of SCM_BOOL_F and
+ * SCM_MATCHES_BITS_IN_COMMON in tags.h for more information.
+ */
+verify (SCM_VALUES_DIFFER_IN_EXACTLY_ONE_BIT_POSITION \
+ (SCM_ELISP_NIL, SCM_EOL));
+
+
#if (SCM_DEBUG_PAIR_ACCESSES == 1)
#include "libguile/ports.h"
diff --git a/libguile/lang.h b/libguile/lang.h
index 47128de..985f5ef 100644
--- a/libguile/lang.h
+++ b/libguile/lang.h
@@ -39,7 +39,7 @@ SCM_INTERNAL void scm_init_lang (void);
#endif /* ! SCM_ENABLE_ELISP */
-#define SCM_NULL_OR_NIL_P(x) (scm_is_null (x) || SCM_NILP (x))
+#define SCM_NULL_OR_NIL_P(x) (scm_is_null_or_lisp_nil (x))
#endif /* SCM_LANG_H */
diff --git a/libguile/eval.i.c b/libguile/eval.i.c
index 99aa265..9da1664 100644
--- a/libguile/eval.i.c
+++ b/libguile/eval.i.c
@@ -304,7 +304,7 @@ dispatch:
while (!scm_is_null (SCM_CDR (x)))
{
SCM test_result = EVALCAR (x, env);
- if (scm_is_false (test_result) || SCM_NILP (test_result))
+ if (scm_is_false_or_lisp_nil (test_result))
RETURN (SCM_BOOL_F);
else
x = SCM_CDR (x);
@@ -442,8 +442,7 @@ dispatch:
xx = SCM_CDR (clause);
proc = EVALCAR (xx, env);
guard_result = SCM_APPLY (proc, arg1, SCM_EOL);
- if (scm_is_true (guard_result)
- && !SCM_NILP (guard_result))
+ if (scm_is_true_and_not_lisp_nil (guard_result))
{
proc = SCM_CDDR (xx);
proc = EVALCAR (proc, env);
@@ -451,7 +450,7 @@ dispatch:
goto apply_proc;
}
}
- else if (scm_is_true (arg1) && !SCM_NILP (arg1))
+ else if (scm_is_true_and_not_lisp_nil (arg1))
{
x = SCM_CDR (clause);
if (scm_is_null (x))
@@ -498,7 +497,7 @@ dispatch:
SCM test_result = EVALCAR (test_form, env);
- while (scm_is_false (test_result) || SCM_NILP (test_result))
+ while (scm_is_false_or_lisp_nil (test_result))
{
{
/* Evaluate body forms. */
@@ -552,7 +551,7 @@ dispatch:
{
SCM test_result = EVALCAR (x, env);
x = SCM_CDR (x); /* then expression */
- if (scm_is_false (test_result) || SCM_NILP (test_result))
+ if (scm_is_false_or_lisp_nil (test_result))
{
x = SCM_CDR (x); /* else expression */
if (scm_is_null (x))
@@ -623,7 +622,7 @@ dispatch:
while (!scm_is_null (SCM_CDR (x)))
{
SCM val = EVALCAR (x, env);
- if (scm_is_true (val) && !SCM_NILP (val))
+ if (scm_is_true_and_not_lisp_nil (val))
RETURN (val);
else
x = SCM_CDR (x);
[-- Attachment #3: vm-fixes.patch --]
[-- Type: text/x-diff, Size: 1873 bytes --]
diff --git a/libguile/vm-i-system.c b/libguile/vm-i-system.c
index d55d6e2..427a2fc 100644
--- a/libguile/vm-i-system.c
+++ b/libguile/vm-i-system.c
@@ -406,12 +406,12 @@ VM_DEFINE_INSTRUCTION (31, br, "br", 2, 0, 0)
VM_DEFINE_INSTRUCTION (32, br_if, "br-if", 2, 0, 0)
{
- BR (!SCM_FALSEP (*sp));
+ BR (scm_is_true_and_not_lisp_nil (*sp));
}
VM_DEFINE_INSTRUCTION (33, br_if_not, "br-if-not", 2, 0, 0)
{
- BR (SCM_FALSEP (*sp));
+ BR (scm_is_false_or_lisp_nil (*sp));
}
VM_DEFINE_INSTRUCTION (34, br_if_eq, "br-if-eq", 2, 0, 0)
@@ -428,12 +428,12 @@ VM_DEFINE_INSTRUCTION (35, br_if_not_eq, "br-if-not-eq", 2, 0, 0)
VM_DEFINE_INSTRUCTION (36, br_if_null, "br-if-null", 2, 0, 0)
{
- BR (SCM_NULLP (*sp));
+ BR (scm_is_null_or_lisp_nil (*sp));
}
VM_DEFINE_INSTRUCTION (37, br_if_not_null, "br-if-not-null", 2, 0, 0)
{
- BR (!SCM_NULLP (*sp));
+ BR (!scm_is_null_or_lisp_nil (*sp));
}
\f
diff --git a/libguile/vm-i-scheme.c b/libguile/vm-i-scheme.c
index 5de39a2..40781ff 100644
--- a/libguile/vm-i-scheme.c
+++ b/libguile/vm-i-scheme.c
@@ -32,13 +32,13 @@
VM_DEFINE_FUNCTION (80, not, "not", 1)
{
ARGS1 (x);
- RETURN (SCM_BOOL (SCM_FALSEP (x)));
+ RETURN (SCM_BOOL (scm_is_false_or_lisp_nil (x)));
}
VM_DEFINE_FUNCTION (81, not_not, "not-not", 1)
{
ARGS1 (x);
- RETURN (SCM_BOOL (!SCM_FALSEP (x)));
+ RETURN (SCM_BOOL (!scm_is_false_or_lisp_nil (x)));
}
VM_DEFINE_FUNCTION (82, eq, "eq?", 2)
@@ -56,13 +56,13 @@ VM_DEFINE_FUNCTION (83, not_eq, "not-eq?", 2)
VM_DEFINE_FUNCTION (84, nullp, "null?", 1)
{
ARGS1 (x);
- RETURN (SCM_BOOL (SCM_NULLP (x)));
+ RETURN (SCM_BOOL (scm_is_null_or_lisp_nil (x)));
}
VM_DEFINE_FUNCTION (85, not_nullp, "not-null?", 1)
{
ARGS1 (x);
- RETURN (SCM_BOOL (!SCM_NULLP (x)));
+ RETURN (SCM_BOOL (!scm_is_null_or_lisp_nil (x)));
}
VM_DEFINE_FUNCTION (86, eqv, "eqv?", 2)
[-- Attachment #4: srfi-1-fixes.patch --]
[-- Type: text/x-diff, Size: 14109 bytes --]
diff --git a/srfi/srfi-1.c b/srfi/srfi-1.c
index 02f46fc..268f1dc 100644
--- a/srfi/srfi-1.c
+++ b/srfi/srfi-1.c
@@ -211,7 +211,7 @@ SCM_DEFINE (scm_srfi1_break, "break", 2, 0, 0,
for ( ; scm_is_pair (lst); lst = SCM_CDR (lst))
{
SCM elem = SCM_CAR (lst);
- if (scm_is_true (pred_tramp (pred, elem)))
+ if (scm_is_true_and_not_lisp_nil (pred_tramp (pred, elem)))
goto done;
/* want this elem, tack it onto the end of ret */
@@ -243,7 +243,7 @@ SCM_DEFINE (scm_srfi1_break_x, "break!", 2, 0, 0,
p = &lst;
for (upto = lst; scm_is_pair (upto); upto = SCM_CDR (upto))
{
- if (scm_is_true (pred_tramp (pred, SCM_CAR (upto))))
+ if (scm_is_true_and_not_lisp_nil (pred_tramp (pred, SCM_CAR (upto))))
goto done;
/* want this element */
@@ -334,7 +334,8 @@ SCM_DEFINE (scm_srfi1_count, "count", 2, 0, 1,
SCM_ASSERT (pred_tramp, pred, SCM_ARG1, FUNC_NAME);
for ( ; scm_is_pair (list1); list1 = SCM_CDR (list1))
- count += scm_is_true (pred_tramp (pred, SCM_CAR (list1)));
+ count += scm_is_true_and_not_lisp_nil (pred_tramp (pred,
+ SCM_CAR (list1)));
/* check below that list1 is a proper list, and done */
end_list1:
@@ -361,8 +362,9 @@ SCM_DEFINE (scm_srfi1_count, "count", 2, 0, 1,
argnum = 3;
break;
}
- count += scm_is_true (pred_tramp
- (pred, SCM_CAR (list1), SCM_CAR (list2)));
+ count += scm_is_true_and_not_lisp_nil (pred_tramp
+ (pred, SCM_CAR (list1),
+ SCM_CAR (list2)));
list1 = SCM_CDR (list1);
list2 = SCM_CDR (list2);
}
@@ -396,7 +398,8 @@ SCM_DEFINE (scm_srfi1_count, "count", 2, 0, 1,
SCM_SIMPLE_VECTOR_SET (vec, i, SCM_CDR (lst)); /* rest of lst */
}
- count += scm_is_true (scm_apply (pred, args, SCM_EOL));
+ count += scm_is_true_and_not_lisp_nil (scm_apply (pred, args,
+ SCM_EOL));
}
}
@@ -452,7 +455,7 @@ SCM_DEFINE (scm_srfi1_delete, "delete", 2, 1, 0,
for ( ; scm_is_pair (lst); lst = SCM_CDR (lst))
{
- if (scm_is_true (equal_p (pred, x, SCM_CAR (lst))))
+ if (scm_is_true_and_not_lisp_nil (equal_p (pred, x, SCM_CAR (lst))))
{
/* delete this element, so copy those at keeplst */
p = list_copy_part (keeplst, count, p);
@@ -509,7 +512,7 @@ SCM_DEFINE (scm_srfi1_delete_x, "delete!", 2, 1, 0,
scm_is_pair (walk);
walk = SCM_CDR (walk))
{
- if (scm_is_true (equal_p (pred, x, SCM_CAR (walk))))
+ if (scm_is_true_and_not_lisp_nil (equal_p (pred, x, SCM_CAR (walk))))
*prev = SCM_CDR (walk);
else
prev = SCM_CDRLOC (walk);
@@ -591,7 +594,7 @@ SCM_DEFINE (scm_srfi1_delete_duplicates, "delete-duplicates", 1, 1, 0,
/* look for item in "ret" list */
for (l = ret; scm_is_pair (l); l = SCM_CDR (l))
{
- if (scm_is_true (equal_p (pred, SCM_CAR (l), item)))
+ if (scm_is_true_and_not_lisp_nil (equal_p (pred, SCM_CAR (l), item)))
{
/* "item" is a duplicate, so copy keeplst onto ret */
duplicate:
@@ -608,7 +611,7 @@ SCM_DEFINE (scm_srfi1_delete_duplicates, "delete-duplicates", 1, 1, 0,
for (i = 0, l = keeplst;
i < count && scm_is_pair (l);
i++, l = SCM_CDR (l))
- if (scm_is_true (equal_p (pred, SCM_CAR (l), item)))
+ if (scm_is_true_and_not_lisp_nil (equal_p (pred, SCM_CAR (l), item)))
goto duplicate;
/* keep this element */
@@ -684,7 +687,8 @@ SCM_DEFINE (scm_srfi1_delete_duplicates_x, "delete-duplicates!", 1, 1, 0,
l = ret;
for (;;)
{
- if (scm_is_true (equal_p (pred, SCM_CAR (l), item)))
+ if (scm_is_true_and_not_lisp_nil (equal_p (pred, SCM_CAR (l),
+ item)))
break; /* equal, forget this element */
if (scm_is_eq (l, endret))
@@ -770,7 +774,7 @@ SCM_DEFINE (scm_srfi1_drop_while, "drop-while", 2, 0, 0,
SCM_ASSERT (pred_tramp, pred, SCM_ARG1, FUNC_NAME);
for ( ; scm_is_pair (lst); lst = SCM_CDR (lst))
- if (scm_is_false (pred_tramp (pred, SCM_CAR (lst))))
+ if (scm_is_false_or_lisp_nil (pred_tramp (pred, SCM_CAR (lst))))
goto done;
SCM_ASSERT_TYPE (SCM_NULL_OR_NIL_P (lst), lst, SCM_ARG2, FUNC_NAME, "list");
@@ -824,7 +828,7 @@ SCM_DEFINE (scm_srfi1_filter_map, "filter-map", 2, 0, 1,
for ( ; scm_is_pair (list1); list1 = SCM_CDR (list1))
{
elem = proc_tramp (proc, SCM_CAR (list1));
- if (scm_is_true (elem))
+ if (scm_is_true_and_not_lisp_nil (elem))
{
newcell = scm_cons (elem, SCM_EOL);
*loc = newcell;
@@ -855,7 +859,7 @@ SCM_DEFINE (scm_srfi1_filter_map, "filter-map", 2, 0, 1,
goto check_lst_and_done;
}
elem = proc_tramp (proc, SCM_CAR (list1), SCM_CAR (list2));
- if (scm_is_true (elem))
+ if (scm_is_true_and_not_lisp_nil (elem))
{
newcell = scm_cons (elem, SCM_EOL);
*loc = newcell;
@@ -895,7 +899,7 @@ SCM_DEFINE (scm_srfi1_filter_map, "filter-map", 2, 0, 1,
}
elem = scm_apply (proc, args, SCM_EOL);
- if (scm_is_true (elem))
+ if (scm_is_true_and_not_lisp_nil (elem))
{
newcell = scm_cons (elem, SCM_EOL);
*loc = newcell;
@@ -924,7 +928,7 @@ SCM_DEFINE (scm_srfi1_find, "find", 2, 0, 0,
for ( ; scm_is_pair (lst); lst = SCM_CDR (lst))
{
SCM elem = SCM_CAR (lst);
- if (scm_is_true (pred_tramp (pred, elem)))
+ if (scm_is_true_and_not_lisp_nil (pred_tramp (pred, elem)))
return elem;
}
SCM_ASSERT_TYPE (SCM_NULL_OR_NIL_P (lst), lst, SCM_ARG2, FUNC_NAME, "list");
@@ -945,7 +949,7 @@ SCM_DEFINE (scm_srfi1_find_tail, "find-tail", 2, 0, 0,
SCM_ASSERT (pred_tramp, pred, SCM_ARG1, FUNC_NAME);
for ( ; scm_is_pair (lst); lst = SCM_CDR (lst))
- if (scm_is_true (pred_tramp (pred, SCM_CAR (lst))))
+ if (scm_is_true_and_not_lisp_nil (pred_tramp (pred, SCM_CAR (lst))))
return lst;
SCM_ASSERT_TYPE (SCM_NULL_OR_NIL_P (lst), lst, SCM_ARG2, FUNC_NAME, "list");
@@ -1121,7 +1125,7 @@ SCM_DEFINE (scm_srfi1_list_index, "list-index", 2, 0, 1,
SCM_ASSERT (pred_tramp, pred, SCM_ARG1, FUNC_NAME);
for ( ; scm_is_pair (list1); n++, list1 = SCM_CDR (list1))
- if (scm_is_true (pred_tramp (pred, SCM_CAR (list1))))
+ if (scm_is_true_and_not_lisp_nil (pred_tramp (pred, SCM_CAR (list1))))
return SCM_I_MAKINUM (n);
/* not found, check below that list1 is a proper list */
@@ -1146,8 +1150,9 @@ SCM_DEFINE (scm_srfi1_list_index, "list-index", 2, 0, 1,
argnum = 3;
break;
}
- if (scm_is_true (pred_tramp (pred,
- SCM_CAR (list1), SCM_CAR (list2))))
+ if (scm_is_true_and_not_lisp_nil (pred_tramp (pred,
+ SCM_CAR (list1),
+ SCM_CAR (list2))))
return SCM_I_MAKINUM (n);
list1 = SCM_CDR (list1);
@@ -1183,7 +1188,7 @@ SCM_DEFINE (scm_srfi1_list_index, "list-index", 2, 0, 1,
SCM_SIMPLE_VECTOR_SET (vec, i, SCM_CDR (lst)); /* rest of lst */
}
- if (scm_is_true (scm_apply (pred, args, SCM_EOL)))
+ if (scm_is_true_and_not_lisp_nil (scm_apply (pred, args, SCM_EOL)))
return SCM_I_MAKINUM (n);
}
}
@@ -1286,7 +1291,8 @@ SCM_DEFINE (scm_srfi1_lset_adjoin, "lset-adjoin", 2, 0, 1,
elem = SCM_CAR (rest);
for (l = lst; scm_is_pair (l); l = SCM_CDR (l))
- if (scm_is_true (equal_tramp (equal, SCM_CAR (l), elem)))
+ if (scm_is_true_and_not_lisp_nil (equal_tramp (equal, SCM_CAR (l),
+ elem)))
goto next_elem; /* elem already in lst, don't add */
SCM_ASSERT_TYPE (SCM_NULL_OR_NIL_P(l), lst, SCM_ARG2, FUNC_NAME, "list");
@@ -1343,7 +1349,8 @@ SCM_DEFINE (scm_srfi1_lset_difference_x, "lset-difference!", 2, 0, 1,
r = SCM_CDR (r), argnum++)
{
for (b = SCM_CAR (r); scm_is_pair (b); b = SCM_CDR (b))
- if (scm_is_true (equal_tramp (equal, elem, SCM_CAR (b))))
+ if (scm_is_true_and_not_lisp_nil (equal_tramp (equal, elem,
+ SCM_CAR (b))))
goto next_elem; /* equal to elem, so drop that elem */
SCM_ASSERT_TYPE (SCM_NULL_OR_NIL_P (b), b, argnum, FUNC_NAME,"list");
@@ -1385,7 +1392,7 @@ check_map_args (SCM argv,
long elt_len;
elt = SCM_SIMPLE_VECTOR_REF (argv, i);
- if (!(scm_is_null (elt) || scm_is_pair (elt)))
+ if (!(scm_is_null_or_lisp_nil (elt) || scm_is_pair (elt)))
goto check_map_error;
elt_len = srfi1_ilength (elt);
@@ -1430,7 +1437,8 @@ scm_srfi1_map (SCM proc, SCM arg1, SCM args)
SCM *pres = &res;
len = srfi1_ilength (arg1);
- SCM_GASSERTn ((scm_is_null (arg1) || scm_is_pair (arg1)) && len >= -1,
+ SCM_GASSERTn ((scm_is_null_or_lisp_nil (arg1) ||
+ scm_is_pair (arg1)) && len >= -1,
g_srfi1_map,
scm_cons2 (proc, arg1, args), SCM_ARG2, s_srfi1_map);
SCM_VALIDATE_REST_ARGUMENT (args);
@@ -1456,7 +1464,7 @@ scm_srfi1_map (SCM proc, SCM arg1, SCM args)
scm_cons2 (proc, arg1, args), SCM_ARG1, s_srfi1_map);
if (len < 0 || (len2 >= 0 && len2 < len))
len = len2;
- SCM_GASSERTn ((scm_is_null (arg2) || scm_is_pair (arg2))
+ SCM_GASSERTn ((scm_is_null_or_lisp_nil (arg2) || scm_is_pair (arg2))
&& len >= 0 && len2 >= -1,
g_srfi1_map,
scm_cons2 (proc, arg1, args),
@@ -1501,7 +1509,8 @@ scm_srfi1_for_each (SCM proc, SCM arg1, SCM args)
{
long i, len;
len = srfi1_ilength (arg1);
- SCM_GASSERTn ((scm_is_null (arg1) || scm_is_pair (arg1)) && len >= -1,
+ SCM_GASSERTn ((scm_is_null_or_lisp_nil (arg1) ||
+ scm_is_pair (arg1)) && len >= -1,
g_srfi1_for_each, scm_cons2 (proc, arg1, args),
SCM_ARG2, s_srfi1_for_each);
SCM_VALIDATE_REST_ARGUMENT (args);
@@ -1528,7 +1537,7 @@ scm_srfi1_for_each (SCM proc, SCM arg1, SCM args)
scm_cons2 (proc, arg1, args), SCM_ARG1, s_srfi1_for_each);
if (len < 0 || (len2 >= 0 && len2 < len))
len = len2;
- SCM_GASSERTn ((scm_is_null (arg2) || scm_is_pair (arg2))
+ SCM_GASSERTn ((scm_is_null_or_lisp_nil (arg2) || scm_is_pair (arg2))
&& len >= 0 && len2 >= -1,
g_srfi1_for_each,
scm_cons2 (proc, arg1, args),
@@ -1593,7 +1602,7 @@ SCM_DEFINE (scm_srfi1_member, "member", 2, 1, 0,
}
for (; !SCM_NULL_OR_NIL_P (lst); lst = SCM_CDR (lst))
{
- if (scm_is_true (equal_p (pred, x, SCM_CAR (lst))))
+ if (scm_is_true_and_not_lisp_nil (equal_p (pred, x, SCM_CAR (lst))))
return lst;
}
return SCM_BOOL_F;
@@ -1621,7 +1630,7 @@ SCM_DEFINE (scm_srfi1_assoc, "assoc", 2, 1, 0,
SCM tmp = SCM_CAR (ls);
SCM_ASSERT_TYPE (scm_is_pair (tmp), alist, SCM_ARG2, FUNC_NAME,
"association list");
- if (scm_is_true (equal_p (pred, key, SCM_CAR (tmp))))
+ if (scm_is_true_and_not_lisp_nil (equal_p (pred, key, SCM_CAR (tmp))))
return tmp;
}
SCM_ASSERT_TYPE (SCM_NULL_OR_NIL_P (ls), alist, SCM_ARG2, FUNC_NAME,
@@ -1685,7 +1694,7 @@ SCM_DEFINE (scm_srfi1_partition, "partition", 2, 0, 0,
elt = SCM_CAR (list);
new_tail = scm_cons (SCM_CAR (list), SCM_EOL);
- if (scm_is_true (call (pred, elt))) {
+ if (scm_is_true_and_not_lisp_nil (call (pred, elt))) {
SCM_SETCDR(kept_tail, new_tail);
kept_tail = new_tail;
}
@@ -1737,7 +1746,7 @@ SCM_DEFINE (scm_srfi1_partition_x, "partition!", 2, 0, 0,
for ( ; scm_is_pair (lst); lst = SCM_CDR (lst))
{
- if (scm_is_true (pred_tramp (pred, SCM_CAR (lst))))
+ if (scm_is_true_and_not_lisp_nil (pred_tramp (pred, SCM_CAR (lst))))
{
*tp = lst;
tp = SCM_CDRLOC (lst);
@@ -1906,7 +1915,7 @@ SCM_DEFINE (scm_srfi1_remove, "remove", 2, 0, 0,
scm_is_pair (walk);
walk = SCM_CDR (walk))
{
- if (scm_is_false (call (pred, SCM_CAR (walk))))
+ if (scm_is_false_or_lisp_nil (call (pred, SCM_CAR (walk))))
{
*prev = scm_cons (SCM_CAR (walk), SCM_EOL);
prev = SCM_CDRLOC (*prev);
@@ -1938,7 +1947,7 @@ SCM_DEFINE (scm_srfi1_remove_x, "remove!", 2, 0, 0,
scm_is_pair (walk);
walk = SCM_CDR (walk))
{
- if (scm_is_false (call (pred, SCM_CAR (walk))))
+ if (scm_is_false_or_lisp_nil (call (pred, SCM_CAR (walk))))
prev = SCM_CDRLOC (walk);
else
*prev = SCM_CDR (walk);
@@ -1987,7 +1996,7 @@ SCM_DEFINE (scm_srfi1_span, "span", 2, 0, 0,
for ( ; scm_is_pair (lst); lst = SCM_CDR (lst))
{
SCM elem = SCM_CAR (lst);
- if (scm_is_false (pred_tramp (pred, elem)))
+ if (scm_is_false_or_lisp_nil (pred_tramp (pred, elem)))
goto done;
/* want this elem, tack it onto the end of ret */
@@ -2019,7 +2028,7 @@ SCM_DEFINE (scm_srfi1_span_x, "span!", 2, 0, 0,
p = &lst;
for (upto = lst; scm_is_pair (upto); upto = SCM_CDR (upto))
{
- if (scm_is_false (pred_tramp (pred, SCM_CAR (upto))))
+ if (scm_is_false_or_lisp_nil (pred_tramp (pred, SCM_CAR (upto))))
goto done;
/* want this element */
@@ -2147,7 +2156,7 @@ SCM_DEFINE (scm_srfi1_take_while, "take-while", 2, 0, 0,
for ( ; scm_is_pair (lst); lst = SCM_CDR (lst))
{
SCM elem = SCM_CAR (lst);
- if (scm_is_false (pred_tramp (pred, elem)))
+ if (scm_is_false_or_lisp_nil (pred_tramp (pred, elem)))
goto done;
/* want this elem, tack it onto the end of ret */
@@ -2178,7 +2187,7 @@ SCM_DEFINE (scm_srfi1_take_while_x, "take-while!", 2, 0, 0,
p = &lst;
for (upto = lst; scm_is_pair (upto); upto = SCM_CDR (upto))
{
- if (scm_is_false (pred_tramp (pred, SCM_CAR (upto))))
+ if (scm_is_false_or_lisp_nil (pred_tramp (pred, SCM_CAR (upto))))
goto done;
/* want this element */
[-- Attachment #5: non-essential.patch --]
[-- Type: text/x-diff, Size: 1138 bytes --]
diff --git a/libguile/discouraged.h b/libguile/discouraged.h
index 1be05f0..0411069 100644
--- a/libguile/discouraged.h
+++ b/libguile/discouraged.h
@@ -54,6 +54,9 @@
/* SCM_BOOL_NOT returns the other boolean.
* The order of ^s here is important for Borland C++ (!?!?!)
+ *
+ * XXX Should this handle %nil properly, and thus be
+ * defined as (scm_from_bool (scm_is_false_or_lisp_nil (x))) ?
*/
#define SCM_BOOL_NOT(x) (SCM_PACK (SCM_UNPACK (x) \
^ (SCM_UNPACK (SCM_BOOL_T) \
diff --git a/libguile/goops.c b/libguile/goops.c
index 1548472..b6234a6 100644
--- a/libguile/goops.c
+++ b/libguile/goops.c
@@ -190,11 +190,12 @@ SCM_DEFINE (scm_class_of, "class-of", 1, 0, 0,
return scm_class_integer;
case scm_tc3_imm24:
+ /* XXX What should be done with SCM_ELISP_NIL? */
if (SCM_CHARP (x))
return scm_class_char;
- else if (scm_is_bool (x))
+ else if (scm_is_bool_and_not_lisp_nil (x))
return scm_class_boolean;
- else if (scm_is_null (x))
+ else if (scm_is_null_and_not_lisp_nil (x))
return scm_class_null;
else
return scm_class_unknown;
^ permalink raw reply related [flat|nested] 11+ messages in thread
* Re: [PATCH] %nil-handling optimization and fixes v1
2009-07-09 16:11 [PATCH] %nil-handling optimization and fixes v1 Mark H Weaver
@ 2009-07-23 21:38 ` Andy Wingo
2009-07-30 22:05 ` Neil Jerram
` (2 more replies)
2009-08-28 7:08 ` Neil Jerram
2009-08-28 7:08 ` Neil Jerram
2 siblings, 3 replies; 11+ messages in thread
From: Andy Wingo @ 2009-07-23 21:38 UTC (permalink / raw)
To: Mark H Weaver; +Cc: guile-devel
Hi Mark,
This is also not a patch review yet :)
On Thu 09 Jul 2009 18:11, Mark H Weaver <mhw@netris.org> writes:
> I added the following macros, whose names explicitly state how %nil
> should be handled. See the comments in the patch for more information
> about these.
>
> scm_is_false_assume_not_lisp_nil scm_is_true_assume_not_lisp_nil
> scm_is_false_and_not_lisp_nil scm_is_true_or_lisp_nil
> scm_is_false_or_lisp_nil scm_is_true_and_not_lisp_nil
>
> scm_is_lisp_false scm_is_lisp_true
>
> scm_is_null_assume_not_lisp_nil
> scm_is_null_and_not_lisp_nil
> scm_is_null_or_lisp_nil
>
> scm_is_bool_and_not_lisp_nil
> scm_is_bool_or_lisp_nil
These are terrible names. But they seem to be the best names for the
concepts we're trying to express. I don't understand all of them yet,
will wait for a review -- unless Neil takes care of that before I do ;-)
> The following already-existing macros are defined as aliases, such
> that their semantics is unchanged (although scm_is_bool used to be a
> function and is now a macro).
>
> scm_is_null --> scm_is_null_and_not_lisp_nil
> scm_is_false --> scm_is_false_and_not_lisp_nil
> scm_is_true --> scm_is_true_or_lisp_nil
> scm_is_bool --> scm_is_bool_and_not_lisp_nil
This part sounds right to me, based on the current semantics.
> (I still believe that these should be changed to versions that handle
> %nil properly, but await approval on that point, so these patches do
> not make those changes)
Yes, this also sounds right to me.
> Also, if the preprocessor macro SCM_ENABLE_ELISP is not true (this
> macro already existed and was used in lang.h), all overheads
> associated with %nil handling are eliminated from the above macros.
Excellent. Hacks like this are excellent :-)
> vm-fixes.patch changes semantics, by fixing %nil handling in the
> following instructions: br-if, br-if-not, br-if-null, br-if-not-null,
> not, not-not, null?, and not-null?
Sounds great in principle, though i have not looked at it
> srfi-1-fixes.patch changes semantics, by fixing %nil handling in
> several functions. Note that this patch (and several other large
> forthcoming patches) will be unnecessary if the scm_is_false,
> scm_is_true, and scm_is_null macros are changed to handle %nil as I
> proposed.
Hm. Perhaps we should decide first.
> non-essential.patch is the last and least important. It doesn't
> change any functionality or implementation. It changes two
> occurrences of scm_is_bool and scm_is_null, in which %nil must *not*
> be treated as a boolean or null, to use newly-added equivalent macros
> which are explicit about how nil should be handled. These changes
> will be needed if scm_is_null is changed as I proposed. It also adds
> a few comments related to %nil handling.
>
> I've run "make check" on recent git master (c4b681fd) with these
> patches applied, and everything seems to work.
Sounds good too.
> I haven't yet run any benchmarks, because I'm not sure how to best do
> that. I doubt the changes will make any noticeable difference except
> possibly in C code which does a lot of tests which include %nil.
Yeah I don't expect too many differences either. Still, nice to clean
up.
Regards,
Andy
--
http://wingolog.org/
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH] %nil-handling optimization and fixes v1
2009-07-23 21:38 ` Andy Wingo
@ 2009-07-30 22:05 ` Neil Jerram
2009-08-30 9:18 ` Neil Jerram
2009-08-30 18:01 ` Mark H Weaver
2 siblings, 0 replies; 11+ messages in thread
From: Neil Jerram @ 2009-07-30 22:05 UTC (permalink / raw)
To: Mark H Weaver; +Cc: Andy Wingo, guile-devel
Andy Wingo <wingo@pobox.com> writes:
> Hi Mark,
>
> This is also not a patch review yet :)
>
> On Thu 09 Jul 2009 18:11, Mark H Weaver <mhw@netris.org> writes:
>
>> I added the following macros, whose names explicitly state how %nil
>> should be handled. See the comments in the patch for more information
>> about these.
Hi Mark,
I'm really sorry I haven't reviewed this patch yet, or commented on
your arguments for handling %nil more pervasively. From skimming the
emails, your arguments look persuasive, but I'm afraid detailed review
will have to wait a bit longer, as I'm going to be on holiday and away
from email for a couple of weeks. I'm sorry about that, and really
appreciate your work on this area.
Regards,
Neil
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH] %nil-handling optimization and fixes v1
2009-07-09 16:11 [PATCH] %nil-handling optimization and fixes v1 Mark H Weaver
2009-07-23 21:38 ` Andy Wingo
@ 2009-08-28 7:08 ` Neil Jerram
2009-08-28 7:11 ` Neil Jerram
2009-08-28 7:08 ` Neil Jerram
2 siblings, 1 reply; 11+ messages in thread
From: Neil Jerram @ 2009-08-28 7:08 UTC (permalink / raw)
To: Mark H Weaver; +Cc: guile-devel
So, finally, here we go with these patches.
Mark H Weaver <mhw@netris.org> writes:
> Attached are patches to optimize %nil handling, along with some fixes
> to %nil-handling bugs, as I outlined in my recent posts.
>
> Four patches are attached. The first.patch is the most important, and
> is a prerequisite for the others. In brief it does the following:
>
> * Renumbers the IFLAG constants.
>
> * Adds several macros related to boolean type tests, null tests, and
> boolean-truth testing (including lisp-style boolean-truth tests).
>
> * Adds compile-time checks to verify the necessary IFLAG numbering
> properties needed for the checks to work properly.
>
> * Changes some existing code to use the new optimized macros, without
> changing the semantics of the code at all (except that scm_is_bool
> is changed from a function to a macro).
>
> I added the following macros, whose names explicitly state how %nil
> should be handled. See the comments in the patch for more information
> about these.
>
> scm_is_false_assume_not_lisp_nil scm_is_true_assume_not_lisp_nil
> scm_is_false_and_not_lisp_nil scm_is_true_or_lisp_nil
> scm_is_false_or_lisp_nil scm_is_true_and_not_lisp_nil
>
> scm_is_lisp_false scm_is_lisp_true
>
> scm_is_null_assume_not_lisp_nil
> scm_is_null_and_not_lisp_nil
> scm_is_null_or_lisp_nil
>
> scm_is_bool_and_not_lisp_nil
> scm_is_bool_or_lisp_nil
>
> The following already-existing macros are defined as aliases, such
> that their semantics is unchanged (although scm_is_bool used to be a
> function and is now a macro).
>
> scm_is_null --> scm_is_null_and_not_lisp_nil
> scm_is_false --> scm_is_false_and_not_lisp_nil
> scm_is_true --> scm_is_true_or_lisp_nil
> scm_is_bool --> scm_is_bool_and_not_lisp_nil
>
> (I still believe that these should be changed to versions that handle
> %nil properly, but await approval on that point, so these patches do
> not make those changes)
>
> Also, if the preprocessor macro SCM_ENABLE_ELISP is not true (this
> macro already existed and was used in lang.h), all overheads
> associated with %nil handling are eliminated from the above macros.
>
>
> vm-fixes.patch changes semantics, by fixing %nil handling in the
> following instructions: br-if, br-if-not, br-if-null, br-if-not-null,
> not, not-not, null?, and not-null?
>
> srfi-1-fixes.patch changes semantics, by fixing %nil handling in
> several functions. Note that this patch (and several other large
> forthcoming patches) will be unnecessary if the scm_is_false,
> scm_is_true, and scm_is_null macros are changed to handle %nil as I
> proposed.
>
> non-essential.patch is the last and least important. It doesn't
> change any functionality or implementation. It changes two
> occurrences of scm_is_bool and scm_is_null, in which %nil must *not*
> be treated as a boolean or null, to use newly-added equivalent macros
> which are explicit about how nil should be handled. These changes
> will be needed if scm_is_null is changed as I proposed. It also adds
> a few comments related to %nil handling.
>
> I've run "make check" on recent git master (c4b681fd) with these
> patches applied, and everything seems to work.
>
> I haven't yet run any benchmarks, because I'm not sure how to best do
> that. I doubt the changes will make any noticeable difference except
> possibly in C code which does a lot of tests which include %nil.
>
> Comments and suggestions solicited.
>
> Best,
> Mark
>
> diff --git a/libguile/tags.h b/libguile/tags.h
> index 3294533..25aea09 100644
> --- a/libguile/tags.h
> +++ b/libguile/tags.h
> @@ -516,12 +516,47 @@ enum scm_tc8_tags
> #define SCM_MAKIFLAG(n) SCM_MAKE_ITAG8 ((n), scm_tc8_flag)
> #define SCM_IFLAGNUM(n) (SCM_ITAG8_DATA (n))
>
> +/*
> + * IMPORTANT NOTE regarding IFLAG numbering!!!
> + *
> + * Several macros depend upon careful IFLAG numbering of SCM_BOOL_F,
> + * SCM_BOOL_T, SCM_ELISP_NIL, SCM_EOL, and the two SCM_XXX_*_DONT_USE
> + * constants. In particular:
> + *
> + * - SCM_BOOL_F and SCM_BOOL_T must differ in exactly one bit position.
> + * (used to implement scm_is_bool_and_not_lisp_nil, aka scm_is_bool)
> + *
> + * - SCM_ELISP_NIL and SCM_BOOL_F must differ in exactly one bit position.
> + * (used to implement scm_is_false_or_lisp_nil and
> + * scm_is_true_and_not_lisp_nil)
> + *
> + * - SCM_ELISP_NIL and SCM_EOL must differ in exactly one bit position.
> + * (used to implement scm_is_null_or_lisp_nil)
> + *
> + * - SCM_ELISP_NIL, SCM_BOOL_F, SCM_EOL, SCM_XXX_ANOTHER_LISP_FALSE_DONT_USE
> + * must all be equal except for two bit positions.
> + * (used to implement scm_is_lisp_false)
> + *
> + * - SCM_ELISP_NIL, SCM_BOOL_F, SCM_BOOL_T, SCM_XXX_ANOTHER_BOOLEAN_DONT_USE
> + * must all be equal except for two bit positions.
> + * (used to implement scm_is_bool_or_lisp_nil)
> + *
> + * These properties allow the aforementioned macros to be implemented
> + * by bitwise ANDing with a mask and then comparing with a constant,
> + * using as a common basis the macro SCM_MATCHES_BITS_IN_COMMON,
> + * defined below. The properties are checked at compile-time using
> + * `verify' macros near the top of boolean.c and pairs.c.
> + */
Appreciate the detailed comments.
> #define SCM_BOOL_F SCM_MAKIFLAG (0)
> -#define SCM_BOOL_T SCM_MAKIFLAG (1)
> -#define SCM_UNDEFINED SCM_MAKIFLAG (2)
> -#define SCM_EOF_VAL SCM_MAKIFLAG (3)
> -#define SCM_EOL SCM_MAKIFLAG (4)
> -#define SCM_UNSPECIFIED SCM_MAKIFLAG (5)
> +#define SCM_ELISP_NIL SCM_MAKIFLAG (1)
> +#define SCM_XXX_ANOTHER_LISP_FALSE_DONT_USE SCM_MAKIFLAG (2)
> +#define SCM_EOL SCM_MAKIFLAG (3)
> +#define SCM_BOOL_T SCM_MAKIFLAG (4)
> +#define SCM_XXX_ANOTHER_BOOLEAN_DONT_USE SCM_MAKIFLAG (5)
> +
> +#define SCM_UNSPECIFIED SCM_MAKIFLAG (6)
> +#define SCM_UNDEFINED SCM_MAKIFLAG (7)
> +#define SCM_EOF_VAL SCM_MAKIFLAG (8)
>
> /* When a variable is unbound this is marked by the SCM_UNDEFINED
> * value. The following is an unbound value which can be handled on
> @@ -531,14 +566,50 @@ enum scm_tc8_tags
> * the code which handles this value in C so that SCM_UNDEFINED can be
> * used instead. It is not ideal to let this kind of unique and
> * strange values loose on the Scheme level. */
> -#define SCM_UNBOUND SCM_MAKIFLAG (6)
> -
> -/* The Elisp nil value. */
> -#define SCM_ELISP_NIL SCM_MAKIFLAG (7)
> -
> +#define SCM_UNBOUND SCM_MAKIFLAG (9)
>
> #define SCM_UNBNDP(x) (scm_is_eq ((x), SCM_UNDEFINED))
>
> +/*
> + * SCM_MATCHES_BITS_IN_COMMON(x,a,b) returns 1 if and only if x
> + * matches both a and b in every bit position where a and b are equal;
> + * otherwise it returns 0. Bit positions where a and b differ are
> + * ignored.
> + *
> + * This is used to efficiently compare against two values which differ
> + * in exactly one bit position, or against four values which differ in
> + * exactly two bit positions. It is the basis for the following
> + * macros:
> + *
> + * scm_is_null_or_lisp_nil,
> + * scm_is_false_or_lisp_nil,
> + * scm_is_true_and_not_lisp_nil,
> + * scm_is_lisp_false,
> + * scm_is_lisp_true,
> + * scm_is_bool_and_not_lisp_nil (aka scm_is_bool)
> + * scm_is_bool_or_lisp_nil.
> + */
> +#define SCM_MATCHES_BITS_IN_COMMON(x,a,b) \
> + ((SCM_UNPACK(x) & ~(SCM_UNPACK(a) ^ SCM_UNPACK(b))) == \
> + (SCM_UNPACK(a) & SCM_UNPACK(b)))
> +
> +/*
> + * These macros are used for compile-time verification that the
> + * constants have the properties needed for the above macro to work
> + * properly.
> + */
> +#define SCM_WITH_LEAST_SIGNIFICANT_1_BIT_CLEARED(x) ((x) & ((x)-1))
> +#define SCM_HAS_EXACTLY_ONE_BIT_SET(x) \
> + ((x) != 0 && SCM_WITH_LEAST_SIGNIFICANT_1_BIT_CLEARED (x) == 0)
I know they're not needed, but I'd still add some more parentheses
here.
> +#define SCM_HAS_EXACTLY_TWO_BITS_SET(x) \
> + (SCM_HAS_EXACTLY_ONE_BIT_SET (SCM_WITH_LEAST_SIGNIFICANT_1_BIT_CLEARED (x)))
> +
> +#define SCM_VALUES_DIFFER_IN_EXACTLY_ONE_BIT_POSITION(a,b) \
> + (SCM_HAS_EXACTLY_ONE_BIT_SET (SCM_UNPACK(a) ^ SCM_UNPACK(b)))
> +#define SCM_VALUES_DIFFER_IN_EXACTLY_TWO_BIT_POSITIONS(a,b,c,d) \
> + (SCM_HAS_EXACTLY_TWO_BITS_SET ((SCM_UNPACK(a) ^ SCM_UNPACK(b)) | \
> + (SCM_UNPACK(b) ^ SCM_UNPACK(c)) | \
> + (SCM_UNPACK(c) ^ SCM_UNPACK(d))))
> \f
I'd like to make it explicit that these macros are not part of the
public libguile API, and we recently agreed on using the
BUILDING_LIBGUILE macro to do this. So we just need to put #ifdef
BUILDING_LIBGUILE ... #endif around them.
> /* Evaluator byte codes ('immediate symbols'). These constants are used only
> diff --git a/libguile/print.c b/libguile/print.c
> index 6c44d59..fd65bf9 100644
> --- a/libguile/print.c
> +++ b/libguile/print.c
> @@ -61,18 +61,17 @@
> static const char *iflagnames[] =
> {
> "#f",
> + "#nil", /* Elisp nil value. Should print from elisp as symbol `nil'. */
> + "#<XXX_ANOTHER_LISP_FALSE_DONT_USE__SHOULD_NOT_EXIST!!>",
> + "()",
> "#t",
> + "#<XXX_ANOTHER_BOOLEAN_DONT_USE__SHOULD_NOT_EXIST!!>",
"SHOULD_NOT_EXIST" might make a future developer think that those
entries should removed from the code. Maybe add a comment to explain
what it really means, or change to "SHOULD_NEVER_BE_SEEN"?
> + "#<unspecified>",
> "#<undefined>",
> "#<eof>",
> - "()",
> - "#<unspecified>",
>
> /* Unbound slot marker for GOOPS. For internal use in GOOPS only. */
> "#<unbound>",
> -
> - /* Elisp nil value. This is its Scheme name; whenever it's printed in
> - * Elisp, it should appear as the symbol `nil'. */
> - "#nil"
> };
>
> SCM_SYMBOL (sym_reader, "reader");
> diff --git a/libguile/boolean.h b/libguile/boolean.h
> index 5a83797..2c480c0 100644
> --- a/libguile/boolean.h
> +++ b/libguile/boolean.h
> @@ -31,16 +31,97 @@
> *
> */
>
> +/*
> + * Use these macros if it's important (for correctness)
> + * that %nil MUST be considered true
> + */
> +#define scm_is_false_and_not_lisp_nil(x) (scm_is_eq ((x), SCM_BOOL_F))
> +#define scm_is_true_or_lisp_nil(x) (!scm_is_eq ((x), SCM_BOOL_F))
> +
> +/*
> + * Use these macros if %nil will never be tested,
> + * for increased efficiency.
> + */
> +#define scm_is_false_assume_not_lisp_nil(x) (scm_is_eq ((x), SCM_BOOL_F))
> +#define scm_is_true_assume_not_lisp_nil(x) (!scm_is_eq ((x), SCM_BOOL_F))
> +
> +/*
> + * See the comments preceeding the definitions of SCM_BOOL_F and
> + * 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_lisp_nil(x) \
> + (SCM_MATCHES_BITS_IN_COMMON ((x), SCM_ELISP_NIL, SCM_BOOL_F))
> +#else
> +# define scm_is_false_or_lisp_nil(x) (scm_is_false_assume_not_lisp_nil (x))
> +#endif
> +#define scm_is_true_and_not_lisp_nil(x) (!scm_is_false_or_lisp_nil (x))
>
> -#define scm_is_false(x) scm_is_eq ((x), SCM_BOOL_F)
> -#define scm_is_true(x) !scm_is_false (x)
> +/* XXX Should these macros treat %nil as false by default? */
> +#define scm_is_false(x) (scm_is_false_and_not_lisp_nil (x))
> +#define scm_is_true(x) (!scm_is_false (x))
> +
> +/*
> + * Since we know SCM_BOOL_F and SCM_BOOL_T differ by exactly one bit,
> + * and that SCM_BOOL_F and SCM_ELISP_NIL differ by exactly one bit,
> + * and that they of course can't be the same bit (or else SCM_BOOL_T
> + * and SCM_ELISP_NIL be would equal), it follows that SCM_BOOL_T and
> + * SCM_ELISP_NIL differ by exactly two bits, and these are the bits
> + * which will be ignored by SCM_MATCHES_BITS_IN_COMMON below.
> + *
> + * See the comments preceeding the definitions of SCM_BOOL_F and
> + * SCM_MATCHES_BITS_IN_COMMON in tags.h for more information.
> + *
> + * If SCM_ENABLE_ELISP is true, then scm_is_bool_or_lisp_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.
> + * Otherwise, it returns 0.
> + */
> +#if SCM_ENABLE_ELISP
> +# define scm_is_bool_or_lisp_nil(x) \
> + (SCM_MATCHES_BITS_IN_COMMON ((x), SCM_BOOL_T, SCM_ELISP_NIL))
> +#else
> +# define scm_is_bool_or_lisp_nil(x) (scm_is_bool_and_not_lisp_nil (x))
> +#endif
> +
> +#define scm_is_bool_and_not_lisp_nil(x) \
> + (SCM_MATCHES_BITS_IN_COMMON ((x), SCM_BOOL_F, SCM_BOOL_T))
> +
> +/* XXX Should scm_is_bool treat %nil as a boolean? */
> +#define scm_is_bool(x) (scm_is_bool_and_not_lisp_nil (x))
>
> -SCM_API int scm_is_bool (SCM x);
> #define scm_from_bool(x) ((x) ? SCM_BOOL_T : SCM_BOOL_F)
> SCM_API int scm_to_bool (SCM x);
>
> \f
>
> +/*
> + * The following macros efficiently implement boolean truth testing as
> + * expected by most lisps, which treat '() aka SCM_EOL as false.
> + *
> + * Since we know SCM_ELISP_NIL and SCM_BOOL_F differ by exactly one
> + * bit, and that SCM_ELISP_NIL and SCM_EOL differ by exactly one bit,
> + * and that they of course can't be the same bit (or else SCM_BOOL_F
> + * and SCM_EOL be would equal), it follows that SCM_BOOL_F and SCM_EOL
> + * differ by exactly two bits, and these are the bits which will be
> + * ignored by SCM_MATCHES_BITS_IN_COMMON below.
> + *
> + * See the comments preceeding the definitions of SCM_BOOL_F and
> + * SCM_MATCHES_BITS_IN_COMMON in tags.h for more information.
> + *
> + * scm_is_lisp_false(x) returns 1 if and only if x is one of the
> + * 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) \
> + (SCM_MATCHES_BITS_IN_COMMON ((x), SCM_BOOL_F, SCM_EOL))
> +# define scm_is_lisp_true(x) (!scm_is_lisp_false(x))
> +#endif
> +
> +\f
> +
> SCM_API SCM scm_not (SCM x);
> SCM_API SCM scm_boolean_p (SCM obj);
>
> diff --git a/libguile/boolean.c b/libguile/boolean.c
> index d79bf79..9a4f896 100644
> --- a/libguile/boolean.c
> +++ b/libguile/boolean.c
> @@ -29,15 +29,37 @@
> #include "libguile/lang.h"
> #include "libguile/tags.h"
>
> +#include "verify.h"
> +
> \f
>
> +/*
> + * These compile-time tests verify the properties needed for the
> + * efficient test macros defined in boolean.h, which are defined in
> + * terms of the SCM_MATCHES_BITS_IN_COMMON macro.
> + *
> + * See the comments preceeding the definitions of SCM_BOOL_F and
> + * SCM_MATCHES_BITS_IN_COMMON in tags.h for more information.
> + */
> +verify (SCM_VALUES_DIFFER_IN_EXACTLY_ONE_BIT_POSITION \
> + (SCM_BOOL_F, SCM_BOOL_T));
> +verify (SCM_VALUES_DIFFER_IN_EXACTLY_ONE_BIT_POSITION \
> + (SCM_ELISP_NIL, SCM_BOOL_F));
> +verify (SCM_VALUES_DIFFER_IN_EXACTLY_ONE_BIT_POSITION \
> + (SCM_ELISP_NIL, SCM_EOL));
> +verify (SCM_VALUES_DIFFER_IN_EXACTLY_TWO_BIT_POSITIONS \
> + (SCM_ELISP_NIL, SCM_BOOL_F, SCM_BOOL_T, \
> + SCM_XXX_ANOTHER_BOOLEAN_DONT_USE));
> +verify (SCM_VALUES_DIFFER_IN_EXACTLY_TWO_BIT_POSITIONS \
> + (SCM_ELISP_NIL, SCM_BOOL_F, SCM_EOL, \
> + SCM_XXX_ANOTHER_LISP_FALSE_DONT_USE));
>
> SCM_DEFINE (scm_not, "not", 1, 0, 0,
> (SCM x),
> "Return @code{#t} iff @var{x} is @code{#f}, else return @code{#f}.")
> #define FUNC_NAME s_scm_not
> {
> - return scm_from_bool (scm_is_false (x) || SCM_NILP (x));
> + return scm_from_bool (scm_is_false_or_lisp_nil (x));
> }
> #undef FUNC_NAME
>
> @@ -47,19 +69,14 @@ SCM_DEFINE (scm_boolean_p, "boolean?", 1, 0, 0,
> "Return @code{#t} iff @var{obj} is either @code{#t} or @code{#f}.")
> #define FUNC_NAME s_scm_boolean_p
> {
> - return scm_from_bool (scm_is_bool (obj) || SCM_NILP (obj));
> + return scm_from_bool (scm_is_bool_or_lisp_nil (obj));
> }
> #undef FUNC_NAME
>
> int
> -scm_is_bool (SCM x)
> -{
> - return scm_is_eq (x, SCM_BOOL_F) || scm_is_eq (x, SCM_BOOL_T);
> -}
> -
> -int
> scm_to_bool (SCM x)
> {
> + /* XXX Should this first test use scm_is_false_or_lisp_nil instead? */
> if (scm_is_eq (x, SCM_BOOL_F))
> return 0;
> else if (scm_is_eq (x, SCM_BOOL_T))
> diff --git a/libguile/pairs.h b/libguile/pairs.h
> index a6d44d2..9c75709 100644
> --- a/libguile/pairs.h
> +++ b/libguile/pairs.h
> @@ -34,7 +34,32 @@
> # define SCM_VALIDATE_PAIR(cell, expr) (expr)
> #endif
>
> -#define scm_is_null(x) (scm_is_eq ((x), SCM_EOL))
> +/*
> + * Use scm_is_null_and_not_lisp_nil if it's important (for correctness)
> + * that %nil must NOT be considered null.
> + */
> +#define scm_is_null_and_not_lisp_nil(x) (scm_is_eq ((x), SCM_EOL))
> +
> +/*
> + * Use scm_is_null_assume_not_lisp_nil if %nil will never be tested,
> + * for increased efficiency.
> + */
> +#define scm_is_null_assume_not_lisp_nil(x) (scm_is_eq ((x), SCM_EOL))
> +
> +/*
> + * See the comments preceeding the definitions of SCM_BOOL_F and
> + * SCM_MATCHES_BITS_IN_COMMON in tags.h for more information on
> + * how the following macro works.
> + */
> +#if SCM_ENABLE_ELISP
> +# define scm_is_null_or_lisp_nil(x) \
> + (SCM_MATCHES_BITS_IN_COMMON ((x), SCM_ELISP_NIL, SCM_EOL))
> +#else
> +# define scm_is_null_or_lisp_nil(x) (scm_is_null_assume_not_lisp_nil (x))
> +#endif
> +
> +/* XXX Should scm_is_null treat %nil as null by default? */
> +#define scm_is_null(x) (scm_is_null_and_not_lisp_nil(x))
>
> #define SCM_CAR(x) (SCM_VALIDATE_PAIR (x, SCM_CELL_OBJECT_0 (x)))
> #define SCM_CDR(x) (SCM_VALIDATE_PAIR (x, SCM_CELL_OBJECT_1 (x)))
> diff --git a/libguile/pairs.c b/libguile/pairs.c
> index aaaeb11..49eef82 100644
> --- a/libguile/pairs.c
> +++ b/libguile/pairs.c
> @@ -27,11 +27,25 @@
>
> #include "libguile/pairs.h"
>
> +#include "verify.h"
> +
> \f
>
> /* {Pairs}
> */
>
> +/*
> + * This compile-time test verifies the properties needed for the
> + * efficient test macro scm_is_null_or_lisp_nil defined in pairs.h,
> + * which is defined in terms of the SCM_MATCHES_BITS_IN_COMMON macro.
> + *
> + * See the comments preceeding the definitions of SCM_BOOL_F and
> + * SCM_MATCHES_BITS_IN_COMMON in tags.h for more information.
> + */
> +verify (SCM_VALUES_DIFFER_IN_EXACTLY_ONE_BIT_POSITION \
> + (SCM_ELISP_NIL, SCM_EOL));
> +
> +
> #if (SCM_DEBUG_PAIR_ACCESSES == 1)
>
> #include "libguile/ports.h"
> diff --git a/libguile/lang.h b/libguile/lang.h
> index 47128de..985f5ef 100644
> --- a/libguile/lang.h
> +++ b/libguile/lang.h
> @@ -39,7 +39,7 @@ SCM_INTERNAL void scm_init_lang (void);
>
> #endif /* ! SCM_ENABLE_ELISP */
>
> -#define SCM_NULL_OR_NIL_P(x) (scm_is_null (x) || SCM_NILP (x))
> +#define SCM_NULL_OR_NIL_P(x) (scm_is_null_or_lisp_nil (x))
>
> #endif /* SCM_LANG_H */
>
> diff --git a/libguile/eval.i.c b/libguile/eval.i.c
> index 99aa265..9da1664 100644
> --- a/libguile/eval.i.c
> +++ b/libguile/eval.i.c
> @@ -304,7 +304,7 @@ dispatch:
> while (!scm_is_null (SCM_CDR (x)))
> {
> SCM test_result = EVALCAR (x, env);
> - if (scm_is_false (test_result) || SCM_NILP (test_result))
> + if (scm_is_false_or_lisp_nil (test_result))
> RETURN (SCM_BOOL_F);
> else
> x = SCM_CDR (x);
> @@ -442,8 +442,7 @@ dispatch:
> xx = SCM_CDR (clause);
> proc = EVALCAR (xx, env);
> guard_result = SCM_APPLY (proc, arg1, SCM_EOL);
> - if (scm_is_true (guard_result)
> - && !SCM_NILP (guard_result))
> + if (scm_is_true_and_not_lisp_nil (guard_result))
> {
> proc = SCM_CDDR (xx);
> proc = EVALCAR (proc, env);
> @@ -451,7 +450,7 @@ dispatch:
> goto apply_proc;
> }
> }
> - else if (scm_is_true (arg1) && !SCM_NILP (arg1))
> + else if (scm_is_true_and_not_lisp_nil (arg1))
> {
> x = SCM_CDR (clause);
> if (scm_is_null (x))
> @@ -498,7 +497,7 @@ dispatch:
>
> SCM test_result = EVALCAR (test_form, env);
>
> - while (scm_is_false (test_result) || SCM_NILP (test_result))
> + while (scm_is_false_or_lisp_nil (test_result))
> {
> {
> /* Evaluate body forms. */
> @@ -552,7 +551,7 @@ dispatch:
> {
> SCM test_result = EVALCAR (x, env);
> x = SCM_CDR (x); /* then expression */
> - if (scm_is_false (test_result) || SCM_NILP (test_result))
> + if (scm_is_false_or_lisp_nil (test_result))
> {
> x = SCM_CDR (x); /* else expression */
> if (scm_is_null (x))
> @@ -623,7 +622,7 @@ dispatch:
> while (!scm_is_null (SCM_CDR (x)))
> {
> SCM val = EVALCAR (x, env);
> - if (scm_is_true (val) && !SCM_NILP (val))
> + if (scm_is_true_and_not_lisp_nil (val))
> RETURN (val);
> else
> x = SCM_CDR (x);
>
> diff --git a/libguile/vm-i-system.c b/libguile/vm-i-system.c
> index d55d6e2..427a2fc 100644
> --- a/libguile/vm-i-system.c
> +++ b/libguile/vm-i-system.c
> @@ -406,12 +406,12 @@ VM_DEFINE_INSTRUCTION (31, br, "br", 2, 0, 0)
>
> VM_DEFINE_INSTRUCTION (32, br_if, "br-if", 2, 0, 0)
> {
> - BR (!SCM_FALSEP (*sp));
> + BR (scm_is_true_and_not_lisp_nil (*sp));
> }
>
> VM_DEFINE_INSTRUCTION (33, br_if_not, "br-if-not", 2, 0, 0)
> {
> - BR (SCM_FALSEP (*sp));
> + BR (scm_is_false_or_lisp_nil (*sp));
> }
>
> VM_DEFINE_INSTRUCTION (34, br_if_eq, "br-if-eq", 2, 0, 0)
> @@ -428,12 +428,12 @@ VM_DEFINE_INSTRUCTION (35, br_if_not_eq, "br-if-not-eq", 2, 0, 0)
>
> VM_DEFINE_INSTRUCTION (36, br_if_null, "br-if-null", 2, 0, 0)
> {
> - BR (SCM_NULLP (*sp));
> + BR (scm_is_null_or_lisp_nil (*sp));
> }
>
> VM_DEFINE_INSTRUCTION (37, br_if_not_null, "br-if-not-null", 2, 0, 0)
> {
> - BR (!SCM_NULLP (*sp));
> + BR (!scm_is_null_or_lisp_nil (*sp));
> }
>
> \f
> diff --git a/libguile/vm-i-scheme.c b/libguile/vm-i-scheme.c
> index 5de39a2..40781ff 100644
> --- a/libguile/vm-i-scheme.c
> +++ b/libguile/vm-i-scheme.c
> @@ -32,13 +32,13 @@
> VM_DEFINE_FUNCTION (80, not, "not", 1)
> {
> ARGS1 (x);
> - RETURN (SCM_BOOL (SCM_FALSEP (x)));
> + RETURN (SCM_BOOL (scm_is_false_or_lisp_nil (x)));
> }
>
> VM_DEFINE_FUNCTION (81, not_not, "not-not", 1)
> {
> ARGS1 (x);
> - RETURN (SCM_BOOL (!SCM_FALSEP (x)));
> + RETURN (SCM_BOOL (!scm_is_false_or_lisp_nil (x)));
> }
>
> VM_DEFINE_FUNCTION (82, eq, "eq?", 2)
> @@ -56,13 +56,13 @@ VM_DEFINE_FUNCTION (83, not_eq, "not-eq?", 2)
> VM_DEFINE_FUNCTION (84, nullp, "null?", 1)
> {
> ARGS1 (x);
> - RETURN (SCM_BOOL (SCM_NULLP (x)));
> + RETURN (SCM_BOOL (scm_is_null_or_lisp_nil (x)));
> }
>
> VM_DEFINE_FUNCTION (85, not_nullp, "not-null?", 1)
> {
> ARGS1 (x);
> - RETURN (SCM_BOOL (!SCM_NULLP (x)));
> + RETURN (SCM_BOOL (!scm_is_null_or_lisp_nil (x)));
> }
>
> VM_DEFINE_FUNCTION (86, eqv, "eqv?", 2)
>
> diff --git a/srfi/srfi-1.c b/srfi/srfi-1.c
> index 02f46fc..268f1dc 100644
> --- a/srfi/srfi-1.c
> +++ b/srfi/srfi-1.c
> @@ -211,7 +211,7 @@ SCM_DEFINE (scm_srfi1_break, "break", 2, 0, 0,
> for ( ; scm_is_pair (lst); lst = SCM_CDR (lst))
> {
> SCM elem = SCM_CAR (lst);
> - if (scm_is_true (pred_tramp (pred, elem)))
> + if (scm_is_true_and_not_lisp_nil (pred_tramp (pred, elem)))
> goto done;
>
> /* want this elem, tack it onto the end of ret */
> @@ -243,7 +243,7 @@ SCM_DEFINE (scm_srfi1_break_x, "break!", 2, 0, 0,
> p = &lst;
> for (upto = lst; scm_is_pair (upto); upto = SCM_CDR (upto))
> {
> - if (scm_is_true (pred_tramp (pred, SCM_CAR (upto))))
> + if (scm_is_true_and_not_lisp_nil (pred_tramp (pred, SCM_CAR (upto))))
> goto done;
>
> /* want this element */
> @@ -334,7 +334,8 @@ SCM_DEFINE (scm_srfi1_count, "count", 2, 0, 1,
> SCM_ASSERT (pred_tramp, pred, SCM_ARG1, FUNC_NAME);
>
> for ( ; scm_is_pair (list1); list1 = SCM_CDR (list1))
> - count += scm_is_true (pred_tramp (pred, SCM_CAR (list1)));
> + count += scm_is_true_and_not_lisp_nil (pred_tramp (pred,
> + SCM_CAR (list1)));
>
> /* check below that list1 is a proper list, and done */
> end_list1:
> @@ -361,8 +362,9 @@ SCM_DEFINE (scm_srfi1_count, "count", 2, 0, 1,
> argnum = 3;
> break;
> }
> - count += scm_is_true (pred_tramp
> - (pred, SCM_CAR (list1), SCM_CAR (list2)));
> + count += scm_is_true_and_not_lisp_nil (pred_tramp
> + (pred, SCM_CAR (list1),
> + SCM_CAR (list2)));
> list1 = SCM_CDR (list1);
> list2 = SCM_CDR (list2);
> }
> @@ -396,7 +398,8 @@ SCM_DEFINE (scm_srfi1_count, "count", 2, 0, 1,
> SCM_SIMPLE_VECTOR_SET (vec, i, SCM_CDR (lst)); /* rest of lst */
> }
>
> - count += scm_is_true (scm_apply (pred, args, SCM_EOL));
> + count += scm_is_true_and_not_lisp_nil (scm_apply (pred, args,
> + SCM_EOL));
> }
> }
>
> @@ -452,7 +455,7 @@ SCM_DEFINE (scm_srfi1_delete, "delete", 2, 1, 0,
>
> for ( ; scm_is_pair (lst); lst = SCM_CDR (lst))
> {
> - if (scm_is_true (equal_p (pred, x, SCM_CAR (lst))))
> + if (scm_is_true_and_not_lisp_nil (equal_p (pred, x, SCM_CAR (lst))))
> {
> /* delete this element, so copy those at keeplst */
> p = list_copy_part (keeplst, count, p);
> @@ -509,7 +512,7 @@ SCM_DEFINE (scm_srfi1_delete_x, "delete!", 2, 1, 0,
> scm_is_pair (walk);
> walk = SCM_CDR (walk))
> {
> - if (scm_is_true (equal_p (pred, x, SCM_CAR (walk))))
> + if (scm_is_true_and_not_lisp_nil (equal_p (pred, x, SCM_CAR (walk))))
> *prev = SCM_CDR (walk);
> else
> prev = SCM_CDRLOC (walk);
> @@ -591,7 +594,7 @@ SCM_DEFINE (scm_srfi1_delete_duplicates, "delete-duplicates", 1, 1, 0,
> /* look for item in "ret" list */
> for (l = ret; scm_is_pair (l); l = SCM_CDR (l))
> {
> - if (scm_is_true (equal_p (pred, SCM_CAR (l), item)))
> + if (scm_is_true_and_not_lisp_nil (equal_p (pred, SCM_CAR (l), item)))
> {
> /* "item" is a duplicate, so copy keeplst onto ret */
> duplicate:
> @@ -608,7 +611,7 @@ SCM_DEFINE (scm_srfi1_delete_duplicates, "delete-duplicates", 1, 1, 0,
> for (i = 0, l = keeplst;
> i < count && scm_is_pair (l);
> i++, l = SCM_CDR (l))
> - if (scm_is_true (equal_p (pred, SCM_CAR (l), item)))
> + if (scm_is_true_and_not_lisp_nil (equal_p (pred, SCM_CAR (l), item)))
> goto duplicate;
>
> /* keep this element */
> @@ -684,7 +687,8 @@ SCM_DEFINE (scm_srfi1_delete_duplicates_x, "delete-duplicates!", 1, 1, 0,
> l = ret;
> for (;;)
> {
> - if (scm_is_true (equal_p (pred, SCM_CAR (l), item)))
> + if (scm_is_true_and_not_lisp_nil (equal_p (pred, SCM_CAR (l),
> + item)))
> break; /* equal, forget this element */
>
> if (scm_is_eq (l, endret))
> @@ -770,7 +774,7 @@ SCM_DEFINE (scm_srfi1_drop_while, "drop-while", 2, 0, 0,
> SCM_ASSERT (pred_tramp, pred, SCM_ARG1, FUNC_NAME);
>
> for ( ; scm_is_pair (lst); lst = SCM_CDR (lst))
> - if (scm_is_false (pred_tramp (pred, SCM_CAR (lst))))
> + if (scm_is_false_or_lisp_nil (pred_tramp (pred, SCM_CAR (lst))))
> goto done;
>
> SCM_ASSERT_TYPE (SCM_NULL_OR_NIL_P (lst), lst, SCM_ARG2, FUNC_NAME, "list");
> @@ -824,7 +828,7 @@ SCM_DEFINE (scm_srfi1_filter_map, "filter-map", 2, 0, 1,
> for ( ; scm_is_pair (list1); list1 = SCM_CDR (list1))
> {
> elem = proc_tramp (proc, SCM_CAR (list1));
> - if (scm_is_true (elem))
> + if (scm_is_true_and_not_lisp_nil (elem))
> {
> newcell = scm_cons (elem, SCM_EOL);
> *loc = newcell;
> @@ -855,7 +859,7 @@ SCM_DEFINE (scm_srfi1_filter_map, "filter-map", 2, 0, 1,
> goto check_lst_and_done;
> }
> elem = proc_tramp (proc, SCM_CAR (list1), SCM_CAR (list2));
> - if (scm_is_true (elem))
> + if (scm_is_true_and_not_lisp_nil (elem))
> {
> newcell = scm_cons (elem, SCM_EOL);
> *loc = newcell;
> @@ -895,7 +899,7 @@ SCM_DEFINE (scm_srfi1_filter_map, "filter-map", 2, 0, 1,
> }
>
> elem = scm_apply (proc, args, SCM_EOL);
> - if (scm_is_true (elem))
> + if (scm_is_true_and_not_lisp_nil (elem))
> {
> newcell = scm_cons (elem, SCM_EOL);
> *loc = newcell;
> @@ -924,7 +928,7 @@ SCM_DEFINE (scm_srfi1_find, "find", 2, 0, 0,
> for ( ; scm_is_pair (lst); lst = SCM_CDR (lst))
> {
> SCM elem = SCM_CAR (lst);
> - if (scm_is_true (pred_tramp (pred, elem)))
> + if (scm_is_true_and_not_lisp_nil (pred_tramp (pred, elem)))
> return elem;
> }
> SCM_ASSERT_TYPE (SCM_NULL_OR_NIL_P (lst), lst, SCM_ARG2, FUNC_NAME, "list");
> @@ -945,7 +949,7 @@ SCM_DEFINE (scm_srfi1_find_tail, "find-tail", 2, 0, 0,
> SCM_ASSERT (pred_tramp, pred, SCM_ARG1, FUNC_NAME);
>
> for ( ; scm_is_pair (lst); lst = SCM_CDR (lst))
> - if (scm_is_true (pred_tramp (pred, SCM_CAR (lst))))
> + if (scm_is_true_and_not_lisp_nil (pred_tramp (pred, SCM_CAR (lst))))
> return lst;
> SCM_ASSERT_TYPE (SCM_NULL_OR_NIL_P (lst), lst, SCM_ARG2, FUNC_NAME, "list");
>
> @@ -1121,7 +1125,7 @@ SCM_DEFINE (scm_srfi1_list_index, "list-index", 2, 0, 1,
> SCM_ASSERT (pred_tramp, pred, SCM_ARG1, FUNC_NAME);
>
> for ( ; scm_is_pair (list1); n++, list1 = SCM_CDR (list1))
> - if (scm_is_true (pred_tramp (pred, SCM_CAR (list1))))
> + if (scm_is_true_and_not_lisp_nil (pred_tramp (pred, SCM_CAR (list1))))
> return SCM_I_MAKINUM (n);
>
> /* not found, check below that list1 is a proper list */
> @@ -1146,8 +1150,9 @@ SCM_DEFINE (scm_srfi1_list_index, "list-index", 2, 0, 1,
> argnum = 3;
> break;
> }
> - if (scm_is_true (pred_tramp (pred,
> - SCM_CAR (list1), SCM_CAR (list2))))
> + if (scm_is_true_and_not_lisp_nil (pred_tramp (pred,
> + SCM_CAR (list1),
> + SCM_CAR (list2))))
> return SCM_I_MAKINUM (n);
>
> list1 = SCM_CDR (list1);
> @@ -1183,7 +1188,7 @@ SCM_DEFINE (scm_srfi1_list_index, "list-index", 2, 0, 1,
> SCM_SIMPLE_VECTOR_SET (vec, i, SCM_CDR (lst)); /* rest of lst */
> }
>
> - if (scm_is_true (scm_apply (pred, args, SCM_EOL)))
> + if (scm_is_true_and_not_lisp_nil (scm_apply (pred, args, SCM_EOL)))
> return SCM_I_MAKINUM (n);
> }
> }
> @@ -1286,7 +1291,8 @@ SCM_DEFINE (scm_srfi1_lset_adjoin, "lset-adjoin", 2, 0, 1,
> elem = SCM_CAR (rest);
>
> for (l = lst; scm_is_pair (l); l = SCM_CDR (l))
> - if (scm_is_true (equal_tramp (equal, SCM_CAR (l), elem)))
> + if (scm_is_true_and_not_lisp_nil (equal_tramp (equal, SCM_CAR (l),
> + elem)))
> goto next_elem; /* elem already in lst, don't add */
>
> SCM_ASSERT_TYPE (SCM_NULL_OR_NIL_P(l), lst, SCM_ARG2, FUNC_NAME, "list");
> @@ -1343,7 +1349,8 @@ SCM_DEFINE (scm_srfi1_lset_difference_x, "lset-difference!", 2, 0, 1,
> r = SCM_CDR (r), argnum++)
> {
> for (b = SCM_CAR (r); scm_is_pair (b); b = SCM_CDR (b))
> - if (scm_is_true (equal_tramp (equal, elem, SCM_CAR (b))))
> + if (scm_is_true_and_not_lisp_nil (equal_tramp (equal, elem,
> + SCM_CAR (b))))
> goto next_elem; /* equal to elem, so drop that elem */
>
> SCM_ASSERT_TYPE (SCM_NULL_OR_NIL_P (b), b, argnum, FUNC_NAME,"list");
> @@ -1385,7 +1392,7 @@ check_map_args (SCM argv,
> long elt_len;
> elt = SCM_SIMPLE_VECTOR_REF (argv, i);
>
> - if (!(scm_is_null (elt) || scm_is_pair (elt)))
> + if (!(scm_is_null_or_lisp_nil (elt) || scm_is_pair (elt)))
> goto check_map_error;
>
> elt_len = srfi1_ilength (elt);
> @@ -1430,7 +1437,8 @@ scm_srfi1_map (SCM proc, SCM arg1, SCM args)
> SCM *pres = &res;
>
> len = srfi1_ilength (arg1);
> - SCM_GASSERTn ((scm_is_null (arg1) || scm_is_pair (arg1)) && len >= -1,
> + SCM_GASSERTn ((scm_is_null_or_lisp_nil (arg1) ||
> + scm_is_pair (arg1)) && len >= -1,
> g_srfi1_map,
> scm_cons2 (proc, arg1, args), SCM_ARG2, s_srfi1_map);
> SCM_VALIDATE_REST_ARGUMENT (args);
> @@ -1456,7 +1464,7 @@ scm_srfi1_map (SCM proc, SCM arg1, SCM args)
> scm_cons2 (proc, arg1, args), SCM_ARG1, s_srfi1_map);
> if (len < 0 || (len2 >= 0 && len2 < len))
> len = len2;
> - SCM_GASSERTn ((scm_is_null (arg2) || scm_is_pair (arg2))
> + SCM_GASSERTn ((scm_is_null_or_lisp_nil (arg2) || scm_is_pair (arg2))
> && len >= 0 && len2 >= -1,
> g_srfi1_map,
> scm_cons2 (proc, arg1, args),
> @@ -1501,7 +1509,8 @@ scm_srfi1_for_each (SCM proc, SCM arg1, SCM args)
> {
> long i, len;
> len = srfi1_ilength (arg1);
> - SCM_GASSERTn ((scm_is_null (arg1) || scm_is_pair (arg1)) && len >= -1,
> + SCM_GASSERTn ((scm_is_null_or_lisp_nil (arg1) ||
> + scm_is_pair (arg1)) && len >= -1,
> g_srfi1_for_each, scm_cons2 (proc, arg1, args),
> SCM_ARG2, s_srfi1_for_each);
> SCM_VALIDATE_REST_ARGUMENT (args);
> @@ -1528,7 +1537,7 @@ scm_srfi1_for_each (SCM proc, SCM arg1, SCM args)
> scm_cons2 (proc, arg1, args), SCM_ARG1, s_srfi1_for_each);
> if (len < 0 || (len2 >= 0 && len2 < len))
> len = len2;
> - SCM_GASSERTn ((scm_is_null (arg2) || scm_is_pair (arg2))
> + SCM_GASSERTn ((scm_is_null_or_lisp_nil (arg2) || scm_is_pair (arg2))
> && len >= 0 && len2 >= -1,
> g_srfi1_for_each,
> scm_cons2 (proc, arg1, args),
> @@ -1593,7 +1602,7 @@ SCM_DEFINE (scm_srfi1_member, "member", 2, 1, 0,
> }
> for (; !SCM_NULL_OR_NIL_P (lst); lst = SCM_CDR (lst))
> {
> - if (scm_is_true (equal_p (pred, x, SCM_CAR (lst))))
> + if (scm_is_true_and_not_lisp_nil (equal_p (pred, x, SCM_CAR (lst))))
> return lst;
> }
> return SCM_BOOL_F;
> @@ -1621,7 +1630,7 @@ SCM_DEFINE (scm_srfi1_assoc, "assoc", 2, 1, 0,
> SCM tmp = SCM_CAR (ls);
> SCM_ASSERT_TYPE (scm_is_pair (tmp), alist, SCM_ARG2, FUNC_NAME,
> "association list");
> - if (scm_is_true (equal_p (pred, key, SCM_CAR (tmp))))
> + if (scm_is_true_and_not_lisp_nil (equal_p (pred, key, SCM_CAR (tmp))))
> return tmp;
> }
> SCM_ASSERT_TYPE (SCM_NULL_OR_NIL_P (ls), alist, SCM_ARG2, FUNC_NAME,
> @@ -1685,7 +1694,7 @@ SCM_DEFINE (scm_srfi1_partition, "partition", 2, 0, 0,
> elt = SCM_CAR (list);
> new_tail = scm_cons (SCM_CAR (list), SCM_EOL);
>
> - if (scm_is_true (call (pred, elt))) {
> + if (scm_is_true_and_not_lisp_nil (call (pred, elt))) {
> SCM_SETCDR(kept_tail, new_tail);
> kept_tail = new_tail;
> }
> @@ -1737,7 +1746,7 @@ SCM_DEFINE (scm_srfi1_partition_x, "partition!", 2, 0, 0,
>
> for ( ; scm_is_pair (lst); lst = SCM_CDR (lst))
> {
> - if (scm_is_true (pred_tramp (pred, SCM_CAR (lst))))
> + if (scm_is_true_and_not_lisp_nil (pred_tramp (pred, SCM_CAR (lst))))
> {
> *tp = lst;
> tp = SCM_CDRLOC (lst);
> @@ -1906,7 +1915,7 @@ SCM_DEFINE (scm_srfi1_remove, "remove", 2, 0, 0,
> scm_is_pair (walk);
> walk = SCM_CDR (walk))
> {
> - if (scm_is_false (call (pred, SCM_CAR (walk))))
> + if (scm_is_false_or_lisp_nil (call (pred, SCM_CAR (walk))))
> {
> *prev = scm_cons (SCM_CAR (walk), SCM_EOL);
> prev = SCM_CDRLOC (*prev);
> @@ -1938,7 +1947,7 @@ SCM_DEFINE (scm_srfi1_remove_x, "remove!", 2, 0, 0,
> scm_is_pair (walk);
> walk = SCM_CDR (walk))
> {
> - if (scm_is_false (call (pred, SCM_CAR (walk))))
> + if (scm_is_false_or_lisp_nil (call (pred, SCM_CAR (walk))))
> prev = SCM_CDRLOC (walk);
> else
> *prev = SCM_CDR (walk);
> @@ -1987,7 +1996,7 @@ SCM_DEFINE (scm_srfi1_span, "span", 2, 0, 0,
> for ( ; scm_is_pair (lst); lst = SCM_CDR (lst))
> {
> SCM elem = SCM_CAR (lst);
> - if (scm_is_false (pred_tramp (pred, elem)))
> + if (scm_is_false_or_lisp_nil (pred_tramp (pred, elem)))
> goto done;
>
> /* want this elem, tack it onto the end of ret */
> @@ -2019,7 +2028,7 @@ SCM_DEFINE (scm_srfi1_span_x, "span!", 2, 0, 0,
> p = &lst;
> for (upto = lst; scm_is_pair (upto); upto = SCM_CDR (upto))
> {
> - if (scm_is_false (pred_tramp (pred, SCM_CAR (upto))))
> + if (scm_is_false_or_lisp_nil (pred_tramp (pred, SCM_CAR (upto))))
> goto done;
>
> /* want this element */
> @@ -2147,7 +2156,7 @@ SCM_DEFINE (scm_srfi1_take_while, "take-while", 2, 0, 0,
> for ( ; scm_is_pair (lst); lst = SCM_CDR (lst))
> {
> SCM elem = SCM_CAR (lst);
> - if (scm_is_false (pred_tramp (pred, elem)))
> + if (scm_is_false_or_lisp_nil (pred_tramp (pred, elem)))
> goto done;
>
> /* want this elem, tack it onto the end of ret */
> @@ -2178,7 +2187,7 @@ SCM_DEFINE (scm_srfi1_take_while_x, "take-while!", 2, 0, 0,
> p = &lst;
> for (upto = lst; scm_is_pair (upto); upto = SCM_CDR (upto))
> {
> - if (scm_is_false (pred_tramp (pred, SCM_CAR (upto))))
> + if (scm_is_false_or_lisp_nil (pred_tramp (pred, SCM_CAR (upto))))
> goto done;
>
> /* want this element */
>
> diff --git a/libguile/discouraged.h b/libguile/discouraged.h
> index 1be05f0..0411069 100644
> --- a/libguile/discouraged.h
> +++ b/libguile/discouraged.h
> @@ -54,6 +54,9 @@
>
> /* SCM_BOOL_NOT returns the other boolean.
> * The order of ^s here is important for Borland C++ (!?!?!)
> + *
> + * XXX Should this handle %nil properly, and thus be
> + * defined as (scm_from_bool (scm_is_false_or_lisp_nil (x))) ?
> */
> #define SCM_BOOL_NOT(x) (SCM_PACK (SCM_UNPACK (x) \
> ^ (SCM_UNPACK (SCM_BOOL_T) \
> diff --git a/libguile/goops.c b/libguile/goops.c
> index 1548472..b6234a6 100644
> --- a/libguile/goops.c
> +++ b/libguile/goops.c
> @@ -190,11 +190,12 @@ SCM_DEFINE (scm_class_of, "class-of", 1, 0, 0,
> return scm_class_integer;
>
> case scm_tc3_imm24:
> + /* XXX What should be done with SCM_ELISP_NIL? */
> if (SCM_CHARP (x))
> return scm_class_char;
> - else if (scm_is_bool (x))
> + else if (scm_is_bool_and_not_lisp_nil (x))
> return scm_class_boolean;
> - else if (scm_is_null (x))
> + else if (scm_is_null_and_not_lisp_nil (x))
> return scm_class_null;
> else
> return scm_class_unknown;
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH] %nil-handling optimization and fixes v1
2009-07-09 16:11 [PATCH] %nil-handling optimization and fixes v1 Mark H Weaver
2009-07-23 21:38 ` Andy Wingo
2009-08-28 7:08 ` Neil Jerram
@ 2009-08-28 7:08 ` Neil Jerram
2009-08-30 13:58 ` Neil Jerram
2 siblings, 1 reply; 11+ messages in thread
From: Neil Jerram @ 2009-08-28 7:08 UTC (permalink / raw)
To: Mark H Weaver; +Cc: guile-devel
So, finally, here we go with these patches. (again! :-))
In summary, they all look great, and I just have a few minor comments
(below) on the first one.
But I guess we need to decide on your suggestion about
> (I still believe that these should be changed to versions that handle
> %nil properly, but await approval on that point, so these patches do
> not make those changes)
because if we agreed this, some of the changes would be needed, or
wouldn't be needed. So I'll review the discussions on that next.
Regards,
Neil
> +/*
> + * IMPORTANT NOTE regarding IFLAG numbering!!!
> + *
> + * Several macros depend upon careful IFLAG numbering of SCM_BOOL_F,
> + * SCM_BOOL_T, SCM_ELISP_NIL, SCM_EOL, and the two SCM_XXX_*_DONT_USE
> + * constants. In particular:
> + *
> + * - SCM_BOOL_F and SCM_BOOL_T must differ in exactly one bit position.
> + * (used to implement scm_is_bool_and_not_lisp_nil, aka scm_is_bool)
> + *
> + * - SCM_ELISP_NIL and SCM_BOOL_F must differ in exactly one bit position.
> + * (used to implement scm_is_false_or_lisp_nil and
> + * scm_is_true_and_not_lisp_nil)
> + *
> + * - SCM_ELISP_NIL and SCM_EOL must differ in exactly one bit position.
> + * (used to implement scm_is_null_or_lisp_nil)
> + *
> + * - SCM_ELISP_NIL, SCM_BOOL_F, SCM_EOL, SCM_XXX_ANOTHER_LISP_FALSE_DONT_USE
> + * must all be equal except for two bit positions.
> + * (used to implement scm_is_lisp_false)
> + *
> + * - SCM_ELISP_NIL, SCM_BOOL_F, SCM_BOOL_T, SCM_XXX_ANOTHER_BOOLEAN_DONT_USE
> + * must all be equal except for two bit positions.
> + * (used to implement scm_is_bool_or_lisp_nil)
> + *
> + * These properties allow the aforementioned macros to be implemented
> + * by bitwise ANDing with a mask and then comparing with a constant,
> + * using as a common basis the macro SCM_MATCHES_BITS_IN_COMMON,
> + * defined below. The properties are checked at compile-time using
> + * `verify' macros near the top of boolean.c and pairs.c.
> + */
Appreciate the detailed comments.
> +/*
> + * These macros are used for compile-time verification that the
> + * constants have the properties needed for the above macro to work
> + * properly.
> + */
> +#define SCM_WITH_LEAST_SIGNIFICANT_1_BIT_CLEARED(x) ((x) & ((x)-1))
> +#define SCM_HAS_EXACTLY_ONE_BIT_SET(x) \
> + ((x) != 0 && SCM_WITH_LEAST_SIGNIFICANT_1_BIT_CLEARED (x) == 0)
I know they're not needed, but I'd still add some more parentheses
here.
> +#define SCM_HAS_EXACTLY_TWO_BITS_SET(x) \
> + (SCM_HAS_EXACTLY_ONE_BIT_SET (SCM_WITH_LEAST_SIGNIFICANT_1_BIT_CLEARED (x)))
> +
> +#define SCM_VALUES_DIFFER_IN_EXACTLY_ONE_BIT_POSITION(a,b) \
> + (SCM_HAS_EXACTLY_ONE_BIT_SET (SCM_UNPACK(a) ^ SCM_UNPACK(b)))
> +#define SCM_VALUES_DIFFER_IN_EXACTLY_TWO_BIT_POSITIONS(a,b,c,d) \
> + (SCM_HAS_EXACTLY_TWO_BITS_SET ((SCM_UNPACK(a) ^ SCM_UNPACK(b)) | \
> + (SCM_UNPACK(b) ^ SCM_UNPACK(c)) | \
> + (SCM_UNPACK(c) ^ SCM_UNPACK(d))))
> \f
I'd like to make it explicit that these macros are not part of the
public libguile API; and we recently agreed on using the
BUILDING_LIBGUILE macro to do this. So we just need to put #ifdef
BUILDING_LIBGUILE ... #endif around them.
> /* Evaluator byte codes ('immediate symbols'). These constants are used only
> diff --git a/libguile/print.c b/libguile/print.c
> index 6c44d59..fd65bf9 100644
> --- a/libguile/print.c
> +++ b/libguile/print.c
> @@ -61,18 +61,17 @@
> static const char *iflagnames[] =
> {
> "#f",
> + "#nil", /* Elisp nil value. Should print from elisp as symbol `nil'. */
> + "#<XXX_ANOTHER_LISP_FALSE_DONT_USE__SHOULD_NOT_EXIST!!>",
> + "()",
> "#t",
> + "#<XXX_ANOTHER_BOOLEAN_DONT_USE__SHOULD_NOT_EXIST!!>",
"SHOULD_NOT_EXIST" might make a future developer think that those
entries should removed from the code. Maybe add a comment to explain
what it really means, or change to "SHOULD_NEVER_BE_SEEN"?
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH] %nil-handling optimization and fixes v1
2009-08-28 7:08 ` Neil Jerram
@ 2009-08-28 7:11 ` Neil Jerram
0 siblings, 0 replies; 11+ messages in thread
From: Neil Jerram @ 2009-08-28 7:11 UTC (permalink / raw)
To: Mark H Weaver; +Cc: guile-devel
I'm sorry, I typed the wrong keys and sent this response prematurely.
I'll finish off the review and send a complete response later on!
Neil
Neil Jerram <neil@ossau.uklinux.net> writes:
> So, finally, here we go with these patches.
>
> Mark H Weaver <mhw@netris.org> writes:
>
>> Attached are patches to optimize %nil handling, along with some fixes
>> to %nil-handling bugs, as I outlined in my recent posts.
>>
>> Four patches are attached. The first.patch is the most important, and
>> is a prerequisite for the others. In brief it does the following:
>>
>> * Renumbers the IFLAG constants.
>>
>> * Adds several macros related to boolean type tests, null tests, and
>> boolean-truth testing (including lisp-style boolean-truth tests).
>>
>> * Adds compile-time checks to verify the necessary IFLAG numbering
>> properties needed for the checks to work properly.
>>
>> * Changes some existing code to use the new optimized macros, without
>> changing the semantics of the code at all (except that scm_is_bool
>> is changed from a function to a macro).
>>
>> I added the following macros, whose names explicitly state how %nil
>> should be handled. See the comments in the patch for more information
>> about these.
>>
>> scm_is_false_assume_not_lisp_nil scm_is_true_assume_not_lisp_nil
>> scm_is_false_and_not_lisp_nil scm_is_true_or_lisp_nil
>> scm_is_false_or_lisp_nil scm_is_true_and_not_lisp_nil
>>
>> scm_is_lisp_false scm_is_lisp_true
>>
>> scm_is_null_assume_not_lisp_nil
>> scm_is_null_and_not_lisp_nil
>> scm_is_null_or_lisp_nil
>>
>> scm_is_bool_and_not_lisp_nil
>> scm_is_bool_or_lisp_nil
>>
>> The following already-existing macros are defined as aliases, such
>> that their semantics is unchanged (although scm_is_bool used to be a
>> function and is now a macro).
>>
>> scm_is_null --> scm_is_null_and_not_lisp_nil
>> scm_is_false --> scm_is_false_and_not_lisp_nil
>> scm_is_true --> scm_is_true_or_lisp_nil
>> scm_is_bool --> scm_is_bool_and_not_lisp_nil
>>
>> (I still believe that these should be changed to versions that handle
>> %nil properly, but await approval on that point, so these patches do
>> not make those changes)
>>
>> Also, if the preprocessor macro SCM_ENABLE_ELISP is not true (this
>> macro already existed and was used in lang.h), all overheads
>> associated with %nil handling are eliminated from the above macros.
>>
>>
>> vm-fixes.patch changes semantics, by fixing %nil handling in the
>> following instructions: br-if, br-if-not, br-if-null, br-if-not-null,
>> not, not-not, null?, and not-null?
>>
>> srfi-1-fixes.patch changes semantics, by fixing %nil handling in
>> several functions. Note that this patch (and several other large
>> forthcoming patches) will be unnecessary if the scm_is_false,
>> scm_is_true, and scm_is_null macros are changed to handle %nil as I
>> proposed.
>>
>> non-essential.patch is the last and least important. It doesn't
>> change any functionality or implementation. It changes two
>> occurrences of scm_is_bool and scm_is_null, in which %nil must *not*
>> be treated as a boolean or null, to use newly-added equivalent macros
>> which are explicit about how nil should be handled. These changes
>> will be needed if scm_is_null is changed as I proposed. It also adds
>> a few comments related to %nil handling.
>>
>> I've run "make check" on recent git master (c4b681fd) with these
>> patches applied, and everything seems to work.
>>
>> I haven't yet run any benchmarks, because I'm not sure how to best do
>> that. I doubt the changes will make any noticeable difference except
>> possibly in C code which does a lot of tests which include %nil.
>>
>> Comments and suggestions solicited.
>>
>> Best,
>> Mark
>>
>> diff --git a/libguile/tags.h b/libguile/tags.h
>> index 3294533..25aea09 100644
>> --- a/libguile/tags.h
>> +++ b/libguile/tags.h
>> @@ -516,12 +516,47 @@ enum scm_tc8_tags
>> #define SCM_MAKIFLAG(n) SCM_MAKE_ITAG8 ((n), scm_tc8_flag)
>> #define SCM_IFLAGNUM(n) (SCM_ITAG8_DATA (n))
>>
>> +/*
>> + * IMPORTANT NOTE regarding IFLAG numbering!!!
>> + *
>> + * Several macros depend upon careful IFLAG numbering of SCM_BOOL_F,
>> + * SCM_BOOL_T, SCM_ELISP_NIL, SCM_EOL, and the two SCM_XXX_*_DONT_USE
>> + * constants. In particular:
>> + *
>> + * - SCM_BOOL_F and SCM_BOOL_T must differ in exactly one bit position.
>> + * (used to implement scm_is_bool_and_not_lisp_nil, aka scm_is_bool)
>> + *
>> + * - SCM_ELISP_NIL and SCM_BOOL_F must differ in exactly one bit position.
>> + * (used to implement scm_is_false_or_lisp_nil and
>> + * scm_is_true_and_not_lisp_nil)
>> + *
>> + * - SCM_ELISP_NIL and SCM_EOL must differ in exactly one bit position.
>> + * (used to implement scm_is_null_or_lisp_nil)
>> + *
>> + * - SCM_ELISP_NIL, SCM_BOOL_F, SCM_EOL, SCM_XXX_ANOTHER_LISP_FALSE_DONT_USE
>> + * must all be equal except for two bit positions.
>> + * (used to implement scm_is_lisp_false)
>> + *
>> + * - SCM_ELISP_NIL, SCM_BOOL_F, SCM_BOOL_T, SCM_XXX_ANOTHER_BOOLEAN_DONT_USE
>> + * must all be equal except for two bit positions.
>> + * (used to implement scm_is_bool_or_lisp_nil)
>> + *
>> + * These properties allow the aforementioned macros to be implemented
>> + * by bitwise ANDing with a mask and then comparing with a constant,
>> + * using as a common basis the macro SCM_MATCHES_BITS_IN_COMMON,
>> + * defined below. The properties are checked at compile-time using
>> + * `verify' macros near the top of boolean.c and pairs.c.
>> + */
>
> Appreciate the detailed comments.
>
>> #define SCM_BOOL_F SCM_MAKIFLAG (0)
>> -#define SCM_BOOL_T SCM_MAKIFLAG (1)
>> -#define SCM_UNDEFINED SCM_MAKIFLAG (2)
>> -#define SCM_EOF_VAL SCM_MAKIFLAG (3)
>> -#define SCM_EOL SCM_MAKIFLAG (4)
>> -#define SCM_UNSPECIFIED SCM_MAKIFLAG (5)
>> +#define SCM_ELISP_NIL SCM_MAKIFLAG (1)
>> +#define SCM_XXX_ANOTHER_LISP_FALSE_DONT_USE SCM_MAKIFLAG (2)
>> +#define SCM_EOL SCM_MAKIFLAG (3)
>> +#define SCM_BOOL_T SCM_MAKIFLAG (4)
>> +#define SCM_XXX_ANOTHER_BOOLEAN_DONT_USE SCM_MAKIFLAG (5)
>> +
>> +#define SCM_UNSPECIFIED SCM_MAKIFLAG (6)
>> +#define SCM_UNDEFINED SCM_MAKIFLAG (7)
>> +#define SCM_EOF_VAL SCM_MAKIFLAG (8)
>>
>> /* When a variable is unbound this is marked by the SCM_UNDEFINED
>> * value. The following is an unbound value which can be handled on
>> @@ -531,14 +566,50 @@ enum scm_tc8_tags
>> * the code which handles this value in C so that SCM_UNDEFINED can be
>> * used instead. It is not ideal to let this kind of unique and
>> * strange values loose on the Scheme level. */
>> -#define SCM_UNBOUND SCM_MAKIFLAG (6)
>> -
>> -/* The Elisp nil value. */
>> -#define SCM_ELISP_NIL SCM_MAKIFLAG (7)
>> -
>> +#define SCM_UNBOUND SCM_MAKIFLAG (9)
>>
>> #define SCM_UNBNDP(x) (scm_is_eq ((x), SCM_UNDEFINED))
>>
>> +/*
>> + * SCM_MATCHES_BITS_IN_COMMON(x,a,b) returns 1 if and only if x
>> + * matches both a and b in every bit position where a and b are equal;
>> + * otherwise it returns 0. Bit positions where a and b differ are
>> + * ignored.
>> + *
>> + * This is used to efficiently compare against two values which differ
>> + * in exactly one bit position, or against four values which differ in
>> + * exactly two bit positions. It is the basis for the following
>> + * macros:
>> + *
>> + * scm_is_null_or_lisp_nil,
>> + * scm_is_false_or_lisp_nil,
>> + * scm_is_true_and_not_lisp_nil,
>> + * scm_is_lisp_false,
>> + * scm_is_lisp_true,
>> + * scm_is_bool_and_not_lisp_nil (aka scm_is_bool)
>> + * scm_is_bool_or_lisp_nil.
>> + */
>> +#define SCM_MATCHES_BITS_IN_COMMON(x,a,b) \
>> + ((SCM_UNPACK(x) & ~(SCM_UNPACK(a) ^ SCM_UNPACK(b))) == \
>> + (SCM_UNPACK(a) & SCM_UNPACK(b)))
>> +
>> +/*
>> + * These macros are used for compile-time verification that the
>> + * constants have the properties needed for the above macro to work
>> + * properly.
>> + */
>> +#define SCM_WITH_LEAST_SIGNIFICANT_1_BIT_CLEARED(x) ((x) & ((x)-1))
>> +#define SCM_HAS_EXACTLY_ONE_BIT_SET(x) \
>> + ((x) != 0 && SCM_WITH_LEAST_SIGNIFICANT_1_BIT_CLEARED (x) == 0)
>
> I know they're not needed, but I'd still add some more parentheses
> here.
>
>> +#define SCM_HAS_EXACTLY_TWO_BITS_SET(x) \
>> + (SCM_HAS_EXACTLY_ONE_BIT_SET (SCM_WITH_LEAST_SIGNIFICANT_1_BIT_CLEARED (x)))
>> +
>> +#define SCM_VALUES_DIFFER_IN_EXACTLY_ONE_BIT_POSITION(a,b) \
>> + (SCM_HAS_EXACTLY_ONE_BIT_SET (SCM_UNPACK(a) ^ SCM_UNPACK(b)))
>> +#define SCM_VALUES_DIFFER_IN_EXACTLY_TWO_BIT_POSITIONS(a,b,c,d) \
>> + (SCM_HAS_EXACTLY_TWO_BITS_SET ((SCM_UNPACK(a) ^ SCM_UNPACK(b)) | \
>> + (SCM_UNPACK(b) ^ SCM_UNPACK(c)) | \
>> + (SCM_UNPACK(c) ^ SCM_UNPACK(d))))
>> \f
>
> I'd like to make it explicit that these macros are not part of the
> public libguile API, and we recently agreed on using the
> BUILDING_LIBGUILE macro to do this. So we just need to put #ifdef
> BUILDING_LIBGUILE ... #endif around them.
>
>> /* Evaluator byte codes ('immediate symbols'). These constants are used only
>> diff --git a/libguile/print.c b/libguile/print.c
>> index 6c44d59..fd65bf9 100644
>> --- a/libguile/print.c
>> +++ b/libguile/print.c
>> @@ -61,18 +61,17 @@
>> static const char *iflagnames[] =
>> {
>> "#f",
>> + "#nil", /* Elisp nil value. Should print from elisp as symbol `nil'. */
>> + "#<XXX_ANOTHER_LISP_FALSE_DONT_USE__SHOULD_NOT_EXIST!!>",
>> + "()",
>> "#t",
>> + "#<XXX_ANOTHER_BOOLEAN_DONT_USE__SHOULD_NOT_EXIST!!>",
>
> "SHOULD_NOT_EXIST" might make a future developer think that those
> entries should removed from the code. Maybe add a comment to explain
> what it really means, or change to "SHOULD_NEVER_BE_SEEN"?
>
>> + "#<unspecified>",
>> "#<undefined>",
>> "#<eof>",
>> - "()",
>> - "#<unspecified>",
>>
>> /* Unbound slot marker for GOOPS. For internal use in GOOPS only. */
>> "#<unbound>",
>> -
>> - /* Elisp nil value. This is its Scheme name; whenever it's printed in
>> - * Elisp, it should appear as the symbol `nil'. */
>> - "#nil"
>> };
>>
>> SCM_SYMBOL (sym_reader, "reader");
>> diff --git a/libguile/boolean.h b/libguile/boolean.h
>> index 5a83797..2c480c0 100644
>> --- a/libguile/boolean.h
>> +++ b/libguile/boolean.h
>> @@ -31,16 +31,97 @@
>> *
>> */
>>
>> +/*
>> + * Use these macros if it's important (for correctness)
>> + * that %nil MUST be considered true
>> + */
>> +#define scm_is_false_and_not_lisp_nil(x) (scm_is_eq ((x), SCM_BOOL_F))
>> +#define scm_is_true_or_lisp_nil(x) (!scm_is_eq ((x), SCM_BOOL_F))
>> +
>> +/*
>> + * Use these macros if %nil will never be tested,
>> + * for increased efficiency.
>> + */
>> +#define scm_is_false_assume_not_lisp_nil(x) (scm_is_eq ((x), SCM_BOOL_F))
>> +#define scm_is_true_assume_not_lisp_nil(x) (!scm_is_eq ((x), SCM_BOOL_F))
>> +
>> +/*
>> + * See the comments preceeding the definitions of SCM_BOOL_F and
>> + * 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_lisp_nil(x) \
>> + (SCM_MATCHES_BITS_IN_COMMON ((x), SCM_ELISP_NIL, SCM_BOOL_F))
>> +#else
>> +# define scm_is_false_or_lisp_nil(x) (scm_is_false_assume_not_lisp_nil (x))
>> +#endif
>> +#define scm_is_true_and_not_lisp_nil(x) (!scm_is_false_or_lisp_nil (x))
>>
>> -#define scm_is_false(x) scm_is_eq ((x), SCM_BOOL_F)
>> -#define scm_is_true(x) !scm_is_false (x)
>> +/* XXX Should these macros treat %nil as false by default? */
>> +#define scm_is_false(x) (scm_is_false_and_not_lisp_nil (x))
>> +#define scm_is_true(x) (!scm_is_false (x))
>> +
>> +/*
>> + * Since we know SCM_BOOL_F and SCM_BOOL_T differ by exactly one bit,
>> + * and that SCM_BOOL_F and SCM_ELISP_NIL differ by exactly one bit,
>> + * and that they of course can't be the same bit (or else SCM_BOOL_T
>> + * and SCM_ELISP_NIL be would equal), it follows that SCM_BOOL_T and
>> + * SCM_ELISP_NIL differ by exactly two bits, and these are the bits
>> + * which will be ignored by SCM_MATCHES_BITS_IN_COMMON below.
>> + *
>> + * See the comments preceeding the definitions of SCM_BOOL_F and
>> + * SCM_MATCHES_BITS_IN_COMMON in tags.h for more information.
>> + *
>> + * If SCM_ENABLE_ELISP is true, then scm_is_bool_or_lisp_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.
>> + * Otherwise, it returns 0.
>> + */
>> +#if SCM_ENABLE_ELISP
>> +# define scm_is_bool_or_lisp_nil(x) \
>> + (SCM_MATCHES_BITS_IN_COMMON ((x), SCM_BOOL_T, SCM_ELISP_NIL))
>> +#else
>> +# define scm_is_bool_or_lisp_nil(x) (scm_is_bool_and_not_lisp_nil (x))
>> +#endif
>> +
>> +#define scm_is_bool_and_not_lisp_nil(x) \
>> + (SCM_MATCHES_BITS_IN_COMMON ((x), SCM_BOOL_F, SCM_BOOL_T))
>> +
>> +/* XXX Should scm_is_bool treat %nil as a boolean? */
>> +#define scm_is_bool(x) (scm_is_bool_and_not_lisp_nil (x))
>>
>> -SCM_API int scm_is_bool (SCM x);
>> #define scm_from_bool(x) ((x) ? SCM_BOOL_T : SCM_BOOL_F)
>> SCM_API int scm_to_bool (SCM x);
>>
>> \f
>>
>> +/*
>> + * The following macros efficiently implement boolean truth testing as
>> + * expected by most lisps, which treat '() aka SCM_EOL as false.
>> + *
>> + * Since we know SCM_ELISP_NIL and SCM_BOOL_F differ by exactly one
>> + * bit, and that SCM_ELISP_NIL and SCM_EOL differ by exactly one bit,
>> + * and that they of course can't be the same bit (or else SCM_BOOL_F
>> + * and SCM_EOL be would equal), it follows that SCM_BOOL_F and SCM_EOL
>> + * differ by exactly two bits, and these are the bits which will be
>> + * ignored by SCM_MATCHES_BITS_IN_COMMON below.
>> + *
>> + * See the comments preceeding the definitions of SCM_BOOL_F and
>> + * SCM_MATCHES_BITS_IN_COMMON in tags.h for more information.
>> + *
>> + * scm_is_lisp_false(x) returns 1 if and only if x is one of the
>> + * 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) \
>> + (SCM_MATCHES_BITS_IN_COMMON ((x), SCM_BOOL_F, SCM_EOL))
>> +# define scm_is_lisp_true(x) (!scm_is_lisp_false(x))
>> +#endif
>> +
>> +\f
>> +
>> SCM_API SCM scm_not (SCM x);
>> SCM_API SCM scm_boolean_p (SCM obj);
>>
>> diff --git a/libguile/boolean.c b/libguile/boolean.c
>> index d79bf79..9a4f896 100644
>> --- a/libguile/boolean.c
>> +++ b/libguile/boolean.c
>> @@ -29,15 +29,37 @@
>> #include "libguile/lang.h"
>> #include "libguile/tags.h"
>>
>> +#include "verify.h"
>> +
>> \f
>>
>> +/*
>> + * These compile-time tests verify the properties needed for the
>> + * efficient test macros defined in boolean.h, which are defined in
>> + * terms of the SCM_MATCHES_BITS_IN_COMMON macro.
>> + *
>> + * See the comments preceeding the definitions of SCM_BOOL_F and
>> + * SCM_MATCHES_BITS_IN_COMMON in tags.h for more information.
>> + */
>> +verify (SCM_VALUES_DIFFER_IN_EXACTLY_ONE_BIT_POSITION \
>> + (SCM_BOOL_F, SCM_BOOL_T));
>> +verify (SCM_VALUES_DIFFER_IN_EXACTLY_ONE_BIT_POSITION \
>> + (SCM_ELISP_NIL, SCM_BOOL_F));
>> +verify (SCM_VALUES_DIFFER_IN_EXACTLY_ONE_BIT_POSITION \
>> + (SCM_ELISP_NIL, SCM_EOL));
>> +verify (SCM_VALUES_DIFFER_IN_EXACTLY_TWO_BIT_POSITIONS \
>> + (SCM_ELISP_NIL, SCM_BOOL_F, SCM_BOOL_T, \
>> + SCM_XXX_ANOTHER_BOOLEAN_DONT_USE));
>> +verify (SCM_VALUES_DIFFER_IN_EXACTLY_TWO_BIT_POSITIONS \
>> + (SCM_ELISP_NIL, SCM_BOOL_F, SCM_EOL, \
>> + SCM_XXX_ANOTHER_LISP_FALSE_DONT_USE));
>>
>> SCM_DEFINE (scm_not, "not", 1, 0, 0,
>> (SCM x),
>> "Return @code{#t} iff @var{x} is @code{#f}, else return @code{#f}.")
>> #define FUNC_NAME s_scm_not
>> {
>> - return scm_from_bool (scm_is_false (x) || SCM_NILP (x));
>> + return scm_from_bool (scm_is_false_or_lisp_nil (x));
>> }
>> #undef FUNC_NAME
>>
>> @@ -47,19 +69,14 @@ SCM_DEFINE (scm_boolean_p, "boolean?", 1, 0, 0,
>> "Return @code{#t} iff @var{obj} is either @code{#t} or @code{#f}.")
>> #define FUNC_NAME s_scm_boolean_p
>> {
>> - return scm_from_bool (scm_is_bool (obj) || SCM_NILP (obj));
>> + return scm_from_bool (scm_is_bool_or_lisp_nil (obj));
>> }
>> #undef FUNC_NAME
>>
>> int
>> -scm_is_bool (SCM x)
>> -{
>> - return scm_is_eq (x, SCM_BOOL_F) || scm_is_eq (x, SCM_BOOL_T);
>> -}
>> -
>> -int
>> scm_to_bool (SCM x)
>> {
>> + /* XXX Should this first test use scm_is_false_or_lisp_nil instead? */
>> if (scm_is_eq (x, SCM_BOOL_F))
>> return 0;
>> else if (scm_is_eq (x, SCM_BOOL_T))
>> diff --git a/libguile/pairs.h b/libguile/pairs.h
>> index a6d44d2..9c75709 100644
>> --- a/libguile/pairs.h
>> +++ b/libguile/pairs.h
>> @@ -34,7 +34,32 @@
>> # define SCM_VALIDATE_PAIR(cell, expr) (expr)
>> #endif
>>
>> -#define scm_is_null(x) (scm_is_eq ((x), SCM_EOL))
>> +/*
>> + * Use scm_is_null_and_not_lisp_nil if it's important (for correctness)
>> + * that %nil must NOT be considered null.
>> + */
>> +#define scm_is_null_and_not_lisp_nil(x) (scm_is_eq ((x), SCM_EOL))
>> +
>> +/*
>> + * Use scm_is_null_assume_not_lisp_nil if %nil will never be tested,
>> + * for increased efficiency.
>> + */
>> +#define scm_is_null_assume_not_lisp_nil(x) (scm_is_eq ((x), SCM_EOL))
>> +
>> +/*
>> + * See the comments preceeding the definitions of SCM_BOOL_F and
>> + * SCM_MATCHES_BITS_IN_COMMON in tags.h for more information on
>> + * how the following macro works.
>> + */
>> +#if SCM_ENABLE_ELISP
>> +# define scm_is_null_or_lisp_nil(x) \
>> + (SCM_MATCHES_BITS_IN_COMMON ((x), SCM_ELISP_NIL, SCM_EOL))
>> +#else
>> +# define scm_is_null_or_lisp_nil(x) (scm_is_null_assume_not_lisp_nil (x))
>> +#endif
>> +
>> +/* XXX Should scm_is_null treat %nil as null by default? */
>> +#define scm_is_null(x) (scm_is_null_and_not_lisp_nil(x))
>>
>> #define SCM_CAR(x) (SCM_VALIDATE_PAIR (x, SCM_CELL_OBJECT_0 (x)))
>> #define SCM_CDR(x) (SCM_VALIDATE_PAIR (x, SCM_CELL_OBJECT_1 (x)))
>> diff --git a/libguile/pairs.c b/libguile/pairs.c
>> index aaaeb11..49eef82 100644
>> --- a/libguile/pairs.c
>> +++ b/libguile/pairs.c
>> @@ -27,11 +27,25 @@
>>
>> #include "libguile/pairs.h"
>>
>> +#include "verify.h"
>> +
>> \f
>>
>> /* {Pairs}
>> */
>>
>> +/*
>> + * This compile-time test verifies the properties needed for the
>> + * efficient test macro scm_is_null_or_lisp_nil defined in pairs.h,
>> + * which is defined in terms of the SCM_MATCHES_BITS_IN_COMMON macro.
>> + *
>> + * See the comments preceeding the definitions of SCM_BOOL_F and
>> + * SCM_MATCHES_BITS_IN_COMMON in tags.h for more information.
>> + */
>> +verify (SCM_VALUES_DIFFER_IN_EXACTLY_ONE_BIT_POSITION \
>> + (SCM_ELISP_NIL, SCM_EOL));
>> +
>> +
>> #if (SCM_DEBUG_PAIR_ACCESSES == 1)
>>
>> #include "libguile/ports.h"
>> diff --git a/libguile/lang.h b/libguile/lang.h
>> index 47128de..985f5ef 100644
>> --- a/libguile/lang.h
>> +++ b/libguile/lang.h
>> @@ -39,7 +39,7 @@ SCM_INTERNAL void scm_init_lang (void);
>>
>> #endif /* ! SCM_ENABLE_ELISP */
>>
>> -#define SCM_NULL_OR_NIL_P(x) (scm_is_null (x) || SCM_NILP (x))
>> +#define SCM_NULL_OR_NIL_P(x) (scm_is_null_or_lisp_nil (x))
>>
>> #endif /* SCM_LANG_H */
>>
>> diff --git a/libguile/eval.i.c b/libguile/eval.i.c
>> index 99aa265..9da1664 100644
>> --- a/libguile/eval.i.c
>> +++ b/libguile/eval.i.c
>> @@ -304,7 +304,7 @@ dispatch:
>> while (!scm_is_null (SCM_CDR (x)))
>> {
>> SCM test_result = EVALCAR (x, env);
>> - if (scm_is_false (test_result) || SCM_NILP (test_result))
>> + if (scm_is_false_or_lisp_nil (test_result))
>> RETURN (SCM_BOOL_F);
>> else
>> x = SCM_CDR (x);
>> @@ -442,8 +442,7 @@ dispatch:
>> xx = SCM_CDR (clause);
>> proc = EVALCAR (xx, env);
>> guard_result = SCM_APPLY (proc, arg1, SCM_EOL);
>> - if (scm_is_true (guard_result)
>> - && !SCM_NILP (guard_result))
>> + if (scm_is_true_and_not_lisp_nil (guard_result))
>> {
>> proc = SCM_CDDR (xx);
>> proc = EVALCAR (proc, env);
>> @@ -451,7 +450,7 @@ dispatch:
>> goto apply_proc;
>> }
>> }
>> - else if (scm_is_true (arg1) && !SCM_NILP (arg1))
>> + else if (scm_is_true_and_not_lisp_nil (arg1))
>> {
>> x = SCM_CDR (clause);
>> if (scm_is_null (x))
>> @@ -498,7 +497,7 @@ dispatch:
>>
>> SCM test_result = EVALCAR (test_form, env);
>>
>> - while (scm_is_false (test_result) || SCM_NILP (test_result))
>> + while (scm_is_false_or_lisp_nil (test_result))
>> {
>> {
>> /* Evaluate body forms. */
>> @@ -552,7 +551,7 @@ dispatch:
>> {
>> SCM test_result = EVALCAR (x, env);
>> x = SCM_CDR (x); /* then expression */
>> - if (scm_is_false (test_result) || SCM_NILP (test_result))
>> + if (scm_is_false_or_lisp_nil (test_result))
>> {
>> x = SCM_CDR (x); /* else expression */
>> if (scm_is_null (x))
>> @@ -623,7 +622,7 @@ dispatch:
>> while (!scm_is_null (SCM_CDR (x)))
>> {
>> SCM val = EVALCAR (x, env);
>> - if (scm_is_true (val) && !SCM_NILP (val))
>> + if (scm_is_true_and_not_lisp_nil (val))
>> RETURN (val);
>> else
>> x = SCM_CDR (x);
>>
>> diff --git a/libguile/vm-i-system.c b/libguile/vm-i-system.c
>> index d55d6e2..427a2fc 100644
>> --- a/libguile/vm-i-system.c
>> +++ b/libguile/vm-i-system.c
>> @@ -406,12 +406,12 @@ VM_DEFINE_INSTRUCTION (31, br, "br", 2, 0, 0)
>>
>> VM_DEFINE_INSTRUCTION (32, br_if, "br-if", 2, 0, 0)
>> {
>> - BR (!SCM_FALSEP (*sp));
>> + BR (scm_is_true_and_not_lisp_nil (*sp));
>> }
>>
>> VM_DEFINE_INSTRUCTION (33, br_if_not, "br-if-not", 2, 0, 0)
>> {
>> - BR (SCM_FALSEP (*sp));
>> + BR (scm_is_false_or_lisp_nil (*sp));
>> }
>>
>> VM_DEFINE_INSTRUCTION (34, br_if_eq, "br-if-eq", 2, 0, 0)
>> @@ -428,12 +428,12 @@ VM_DEFINE_INSTRUCTION (35, br_if_not_eq, "br-if-not-eq", 2, 0, 0)
>>
>> VM_DEFINE_INSTRUCTION (36, br_if_null, "br-if-null", 2, 0, 0)
>> {
>> - BR (SCM_NULLP (*sp));
>> + BR (scm_is_null_or_lisp_nil (*sp));
>> }
>>
>> VM_DEFINE_INSTRUCTION (37, br_if_not_null, "br-if-not-null", 2, 0, 0)
>> {
>> - BR (!SCM_NULLP (*sp));
>> + BR (!scm_is_null_or_lisp_nil (*sp));
>> }
>>
>> \f
>> diff --git a/libguile/vm-i-scheme.c b/libguile/vm-i-scheme.c
>> index 5de39a2..40781ff 100644
>> --- a/libguile/vm-i-scheme.c
>> +++ b/libguile/vm-i-scheme.c
>> @@ -32,13 +32,13 @@
>> VM_DEFINE_FUNCTION (80, not, "not", 1)
>> {
>> ARGS1 (x);
>> - RETURN (SCM_BOOL (SCM_FALSEP (x)));
>> + RETURN (SCM_BOOL (scm_is_false_or_lisp_nil (x)));
>> }
>>
>> VM_DEFINE_FUNCTION (81, not_not, "not-not", 1)
>> {
>> ARGS1 (x);
>> - RETURN (SCM_BOOL (!SCM_FALSEP (x)));
>> + RETURN (SCM_BOOL (!scm_is_false_or_lisp_nil (x)));
>> }
>>
>> VM_DEFINE_FUNCTION (82, eq, "eq?", 2)
>> @@ -56,13 +56,13 @@ VM_DEFINE_FUNCTION (83, not_eq, "not-eq?", 2)
>> VM_DEFINE_FUNCTION (84, nullp, "null?", 1)
>> {
>> ARGS1 (x);
>> - RETURN (SCM_BOOL (SCM_NULLP (x)));
>> + RETURN (SCM_BOOL (scm_is_null_or_lisp_nil (x)));
>> }
>>
>> VM_DEFINE_FUNCTION (85, not_nullp, "not-null?", 1)
>> {
>> ARGS1 (x);
>> - RETURN (SCM_BOOL (!SCM_NULLP (x)));
>> + RETURN (SCM_BOOL (!scm_is_null_or_lisp_nil (x)));
>> }
>>
>> VM_DEFINE_FUNCTION (86, eqv, "eqv?", 2)
>>
>> diff --git a/srfi/srfi-1.c b/srfi/srfi-1.c
>> index 02f46fc..268f1dc 100644
>> --- a/srfi/srfi-1.c
>> +++ b/srfi/srfi-1.c
>> @@ -211,7 +211,7 @@ SCM_DEFINE (scm_srfi1_break, "break", 2, 0, 0,
>> for ( ; scm_is_pair (lst); lst = SCM_CDR (lst))
>> {
>> SCM elem = SCM_CAR (lst);
>> - if (scm_is_true (pred_tramp (pred, elem)))
>> + if (scm_is_true_and_not_lisp_nil (pred_tramp (pred, elem)))
>> goto done;
>>
>> /* want this elem, tack it onto the end of ret */
>> @@ -243,7 +243,7 @@ SCM_DEFINE (scm_srfi1_break_x, "break!", 2, 0, 0,
>> p = &lst;
>> for (upto = lst; scm_is_pair (upto); upto = SCM_CDR (upto))
>> {
>> - if (scm_is_true (pred_tramp (pred, SCM_CAR (upto))))
>> + if (scm_is_true_and_not_lisp_nil (pred_tramp (pred, SCM_CAR (upto))))
>> goto done;
>>
>> /* want this element */
>> @@ -334,7 +334,8 @@ SCM_DEFINE (scm_srfi1_count, "count", 2, 0, 1,
>> SCM_ASSERT (pred_tramp, pred, SCM_ARG1, FUNC_NAME);
>>
>> for ( ; scm_is_pair (list1); list1 = SCM_CDR (list1))
>> - count += scm_is_true (pred_tramp (pred, SCM_CAR (list1)));
>> + count += scm_is_true_and_not_lisp_nil (pred_tramp (pred,
>> + SCM_CAR (list1)));
>>
>> /* check below that list1 is a proper list, and done */
>> end_list1:
>> @@ -361,8 +362,9 @@ SCM_DEFINE (scm_srfi1_count, "count", 2, 0, 1,
>> argnum = 3;
>> break;
>> }
>> - count += scm_is_true (pred_tramp
>> - (pred, SCM_CAR (list1), SCM_CAR (list2)));
>> + count += scm_is_true_and_not_lisp_nil (pred_tramp
>> + (pred, SCM_CAR (list1),
>> + SCM_CAR (list2)));
>> list1 = SCM_CDR (list1);
>> list2 = SCM_CDR (list2);
>> }
>> @@ -396,7 +398,8 @@ SCM_DEFINE (scm_srfi1_count, "count", 2, 0, 1,
>> SCM_SIMPLE_VECTOR_SET (vec, i, SCM_CDR (lst)); /* rest of lst */
>> }
>>
>> - count += scm_is_true (scm_apply (pred, args, SCM_EOL));
>> + count += scm_is_true_and_not_lisp_nil (scm_apply (pred, args,
>> + SCM_EOL));
>> }
>> }
>>
>> @@ -452,7 +455,7 @@ SCM_DEFINE (scm_srfi1_delete, "delete", 2, 1, 0,
>>
>> for ( ; scm_is_pair (lst); lst = SCM_CDR (lst))
>> {
>> - if (scm_is_true (equal_p (pred, x, SCM_CAR (lst))))
>> + if (scm_is_true_and_not_lisp_nil (equal_p (pred, x, SCM_CAR (lst))))
>> {
>> /* delete this element, so copy those at keeplst */
>> p = list_copy_part (keeplst, count, p);
>> @@ -509,7 +512,7 @@ SCM_DEFINE (scm_srfi1_delete_x, "delete!", 2, 1, 0,
>> scm_is_pair (walk);
>> walk = SCM_CDR (walk))
>> {
>> - if (scm_is_true (equal_p (pred, x, SCM_CAR (walk))))
>> + if (scm_is_true_and_not_lisp_nil (equal_p (pred, x, SCM_CAR (walk))))
>> *prev = SCM_CDR (walk);
>> else
>> prev = SCM_CDRLOC (walk);
>> @@ -591,7 +594,7 @@ SCM_DEFINE (scm_srfi1_delete_duplicates, "delete-duplicates", 1, 1, 0,
>> /* look for item in "ret" list */
>> for (l = ret; scm_is_pair (l); l = SCM_CDR (l))
>> {
>> - if (scm_is_true (equal_p (pred, SCM_CAR (l), item)))
>> + if (scm_is_true_and_not_lisp_nil (equal_p (pred, SCM_CAR (l), item)))
>> {
>> /* "item" is a duplicate, so copy keeplst onto ret */
>> duplicate:
>> @@ -608,7 +611,7 @@ SCM_DEFINE (scm_srfi1_delete_duplicates, "delete-duplicates", 1, 1, 0,
>> for (i = 0, l = keeplst;
>> i < count && scm_is_pair (l);
>> i++, l = SCM_CDR (l))
>> - if (scm_is_true (equal_p (pred, SCM_CAR (l), item)))
>> + if (scm_is_true_and_not_lisp_nil (equal_p (pred, SCM_CAR (l), item)))
>> goto duplicate;
>>
>> /* keep this element */
>> @@ -684,7 +687,8 @@ SCM_DEFINE (scm_srfi1_delete_duplicates_x, "delete-duplicates!", 1, 1, 0,
>> l = ret;
>> for (;;)
>> {
>> - if (scm_is_true (equal_p (pred, SCM_CAR (l), item)))
>> + if (scm_is_true_and_not_lisp_nil (equal_p (pred, SCM_CAR (l),
>> + item)))
>> break; /* equal, forget this element */
>>
>> if (scm_is_eq (l, endret))
>> @@ -770,7 +774,7 @@ SCM_DEFINE (scm_srfi1_drop_while, "drop-while", 2, 0, 0,
>> SCM_ASSERT (pred_tramp, pred, SCM_ARG1, FUNC_NAME);
>>
>> for ( ; scm_is_pair (lst); lst = SCM_CDR (lst))
>> - if (scm_is_false (pred_tramp (pred, SCM_CAR (lst))))
>> + if (scm_is_false_or_lisp_nil (pred_tramp (pred, SCM_CAR (lst))))
>> goto done;
>>
>> SCM_ASSERT_TYPE (SCM_NULL_OR_NIL_P (lst), lst, SCM_ARG2, FUNC_NAME, "list");
>> @@ -824,7 +828,7 @@ SCM_DEFINE (scm_srfi1_filter_map, "filter-map", 2, 0, 1,
>> for ( ; scm_is_pair (list1); list1 = SCM_CDR (list1))
>> {
>> elem = proc_tramp (proc, SCM_CAR (list1));
>> - if (scm_is_true (elem))
>> + if (scm_is_true_and_not_lisp_nil (elem))
>> {
>> newcell = scm_cons (elem, SCM_EOL);
>> *loc = newcell;
>> @@ -855,7 +859,7 @@ SCM_DEFINE (scm_srfi1_filter_map, "filter-map", 2, 0, 1,
>> goto check_lst_and_done;
>> }
>> elem = proc_tramp (proc, SCM_CAR (list1), SCM_CAR (list2));
>> - if (scm_is_true (elem))
>> + if (scm_is_true_and_not_lisp_nil (elem))
>> {
>> newcell = scm_cons (elem, SCM_EOL);
>> *loc = newcell;
>> @@ -895,7 +899,7 @@ SCM_DEFINE (scm_srfi1_filter_map, "filter-map", 2, 0, 1,
>> }
>>
>> elem = scm_apply (proc, args, SCM_EOL);
>> - if (scm_is_true (elem))
>> + if (scm_is_true_and_not_lisp_nil (elem))
>> {
>> newcell = scm_cons (elem, SCM_EOL);
>> *loc = newcell;
>> @@ -924,7 +928,7 @@ SCM_DEFINE (scm_srfi1_find, "find", 2, 0, 0,
>> for ( ; scm_is_pair (lst); lst = SCM_CDR (lst))
>> {
>> SCM elem = SCM_CAR (lst);
>> - if (scm_is_true (pred_tramp (pred, elem)))
>> + if (scm_is_true_and_not_lisp_nil (pred_tramp (pred, elem)))
>> return elem;
>> }
>> SCM_ASSERT_TYPE (SCM_NULL_OR_NIL_P (lst), lst, SCM_ARG2, FUNC_NAME, "list");
>> @@ -945,7 +949,7 @@ SCM_DEFINE (scm_srfi1_find_tail, "find-tail", 2, 0, 0,
>> SCM_ASSERT (pred_tramp, pred, SCM_ARG1, FUNC_NAME);
>>
>> for ( ; scm_is_pair (lst); lst = SCM_CDR (lst))
>> - if (scm_is_true (pred_tramp (pred, SCM_CAR (lst))))
>> + if (scm_is_true_and_not_lisp_nil (pred_tramp (pred, SCM_CAR (lst))))
>> return lst;
>> SCM_ASSERT_TYPE (SCM_NULL_OR_NIL_P (lst), lst, SCM_ARG2, FUNC_NAME, "list");
>>
>> @@ -1121,7 +1125,7 @@ SCM_DEFINE (scm_srfi1_list_index, "list-index", 2, 0, 1,
>> SCM_ASSERT (pred_tramp, pred, SCM_ARG1, FUNC_NAME);
>>
>> for ( ; scm_is_pair (list1); n++, list1 = SCM_CDR (list1))
>> - if (scm_is_true (pred_tramp (pred, SCM_CAR (list1))))
>> + if (scm_is_true_and_not_lisp_nil (pred_tramp (pred, SCM_CAR (list1))))
>> return SCM_I_MAKINUM (n);
>>
>> /* not found, check below that list1 is a proper list */
>> @@ -1146,8 +1150,9 @@ SCM_DEFINE (scm_srfi1_list_index, "list-index", 2, 0, 1,
>> argnum = 3;
>> break;
>> }
>> - if (scm_is_true (pred_tramp (pred,
>> - SCM_CAR (list1), SCM_CAR (list2))))
>> + if (scm_is_true_and_not_lisp_nil (pred_tramp (pred,
>> + SCM_CAR (list1),
>> + SCM_CAR (list2))))
>> return SCM_I_MAKINUM (n);
>>
>> list1 = SCM_CDR (list1);
>> @@ -1183,7 +1188,7 @@ SCM_DEFINE (scm_srfi1_list_index, "list-index", 2, 0, 1,
>> SCM_SIMPLE_VECTOR_SET (vec, i, SCM_CDR (lst)); /* rest of lst */
>> }
>>
>> - if (scm_is_true (scm_apply (pred, args, SCM_EOL)))
>> + if (scm_is_true_and_not_lisp_nil (scm_apply (pred, args, SCM_EOL)))
>> return SCM_I_MAKINUM (n);
>> }
>> }
>> @@ -1286,7 +1291,8 @@ SCM_DEFINE (scm_srfi1_lset_adjoin, "lset-adjoin", 2, 0, 1,
>> elem = SCM_CAR (rest);
>>
>> for (l = lst; scm_is_pair (l); l = SCM_CDR (l))
>> - if (scm_is_true (equal_tramp (equal, SCM_CAR (l), elem)))
>> + if (scm_is_true_and_not_lisp_nil (equal_tramp (equal, SCM_CAR (l),
>> + elem)))
>> goto next_elem; /* elem already in lst, don't add */
>>
>> SCM_ASSERT_TYPE (SCM_NULL_OR_NIL_P(l), lst, SCM_ARG2, FUNC_NAME, "list");
>> @@ -1343,7 +1349,8 @@ SCM_DEFINE (scm_srfi1_lset_difference_x, "lset-difference!", 2, 0, 1,
>> r = SCM_CDR (r), argnum++)
>> {
>> for (b = SCM_CAR (r); scm_is_pair (b); b = SCM_CDR (b))
>> - if (scm_is_true (equal_tramp (equal, elem, SCM_CAR (b))))
>> + if (scm_is_true_and_not_lisp_nil (equal_tramp (equal, elem,
>> + SCM_CAR (b))))
>> goto next_elem; /* equal to elem, so drop that elem */
>>
>> SCM_ASSERT_TYPE (SCM_NULL_OR_NIL_P (b), b, argnum, FUNC_NAME,"list");
>> @@ -1385,7 +1392,7 @@ check_map_args (SCM argv,
>> long elt_len;
>> elt = SCM_SIMPLE_VECTOR_REF (argv, i);
>>
>> - if (!(scm_is_null (elt) || scm_is_pair (elt)))
>> + if (!(scm_is_null_or_lisp_nil (elt) || scm_is_pair (elt)))
>> goto check_map_error;
>>
>> elt_len = srfi1_ilength (elt);
>> @@ -1430,7 +1437,8 @@ scm_srfi1_map (SCM proc, SCM arg1, SCM args)
>> SCM *pres = &res;
>>
>> len = srfi1_ilength (arg1);
>> - SCM_GASSERTn ((scm_is_null (arg1) || scm_is_pair (arg1)) && len >= -1,
>> + SCM_GASSERTn ((scm_is_null_or_lisp_nil (arg1) ||
>> + scm_is_pair (arg1)) && len >= -1,
>> g_srfi1_map,
>> scm_cons2 (proc, arg1, args), SCM_ARG2, s_srfi1_map);
>> SCM_VALIDATE_REST_ARGUMENT (args);
>> @@ -1456,7 +1464,7 @@ scm_srfi1_map (SCM proc, SCM arg1, SCM args)
>> scm_cons2 (proc, arg1, args), SCM_ARG1, s_srfi1_map);
>> if (len < 0 || (len2 >= 0 && len2 < len))
>> len = len2;
>> - SCM_GASSERTn ((scm_is_null (arg2) || scm_is_pair (arg2))
>> + SCM_GASSERTn ((scm_is_null_or_lisp_nil (arg2) || scm_is_pair (arg2))
>> && len >= 0 && len2 >= -1,
>> g_srfi1_map,
>> scm_cons2 (proc, arg1, args),
>> @@ -1501,7 +1509,8 @@ scm_srfi1_for_each (SCM proc, SCM arg1, SCM args)
>> {
>> long i, len;
>> len = srfi1_ilength (arg1);
>> - SCM_GASSERTn ((scm_is_null (arg1) || scm_is_pair (arg1)) && len >= -1,
>> + SCM_GASSERTn ((scm_is_null_or_lisp_nil (arg1) ||
>> + scm_is_pair (arg1)) && len >= -1,
>> g_srfi1_for_each, scm_cons2 (proc, arg1, args),
>> SCM_ARG2, s_srfi1_for_each);
>> SCM_VALIDATE_REST_ARGUMENT (args);
>> @@ -1528,7 +1537,7 @@ scm_srfi1_for_each (SCM proc, SCM arg1, SCM args)
>> scm_cons2 (proc, arg1, args), SCM_ARG1, s_srfi1_for_each);
>> if (len < 0 || (len2 >= 0 && len2 < len))
>> len = len2;
>> - SCM_GASSERTn ((scm_is_null (arg2) || scm_is_pair (arg2))
>> + SCM_GASSERTn ((scm_is_null_or_lisp_nil (arg2) || scm_is_pair (arg2))
>> && len >= 0 && len2 >= -1,
>> g_srfi1_for_each,
>> scm_cons2 (proc, arg1, args),
>> @@ -1593,7 +1602,7 @@ SCM_DEFINE (scm_srfi1_member, "member", 2, 1, 0,
>> }
>> for (; !SCM_NULL_OR_NIL_P (lst); lst = SCM_CDR (lst))
>> {
>> - if (scm_is_true (equal_p (pred, x, SCM_CAR (lst))))
>> + if (scm_is_true_and_not_lisp_nil (equal_p (pred, x, SCM_CAR (lst))))
>> return lst;
>> }
>> return SCM_BOOL_F;
>> @@ -1621,7 +1630,7 @@ SCM_DEFINE (scm_srfi1_assoc, "assoc", 2, 1, 0,
>> SCM tmp = SCM_CAR (ls);
>> SCM_ASSERT_TYPE (scm_is_pair (tmp), alist, SCM_ARG2, FUNC_NAME,
>> "association list");
>> - if (scm_is_true (equal_p (pred, key, SCM_CAR (tmp))))
>> + if (scm_is_true_and_not_lisp_nil (equal_p (pred, key, SCM_CAR (tmp))))
>> return tmp;
>> }
>> SCM_ASSERT_TYPE (SCM_NULL_OR_NIL_P (ls), alist, SCM_ARG2, FUNC_NAME,
>> @@ -1685,7 +1694,7 @@ SCM_DEFINE (scm_srfi1_partition, "partition", 2, 0, 0,
>> elt = SCM_CAR (list);
>> new_tail = scm_cons (SCM_CAR (list), SCM_EOL);
>>
>> - if (scm_is_true (call (pred, elt))) {
>> + if (scm_is_true_and_not_lisp_nil (call (pred, elt))) {
>> SCM_SETCDR(kept_tail, new_tail);
>> kept_tail = new_tail;
>> }
>> @@ -1737,7 +1746,7 @@ SCM_DEFINE (scm_srfi1_partition_x, "partition!", 2, 0, 0,
>>
>> for ( ; scm_is_pair (lst); lst = SCM_CDR (lst))
>> {
>> - if (scm_is_true (pred_tramp (pred, SCM_CAR (lst))))
>> + if (scm_is_true_and_not_lisp_nil (pred_tramp (pred, SCM_CAR (lst))))
>> {
>> *tp = lst;
>> tp = SCM_CDRLOC (lst);
>> @@ -1906,7 +1915,7 @@ SCM_DEFINE (scm_srfi1_remove, "remove", 2, 0, 0,
>> scm_is_pair (walk);
>> walk = SCM_CDR (walk))
>> {
>> - if (scm_is_false (call (pred, SCM_CAR (walk))))
>> + if (scm_is_false_or_lisp_nil (call (pred, SCM_CAR (walk))))
>> {
>> *prev = scm_cons (SCM_CAR (walk), SCM_EOL);
>> prev = SCM_CDRLOC (*prev);
>> @@ -1938,7 +1947,7 @@ SCM_DEFINE (scm_srfi1_remove_x, "remove!", 2, 0, 0,
>> scm_is_pair (walk);
>> walk = SCM_CDR (walk))
>> {
>> - if (scm_is_false (call (pred, SCM_CAR (walk))))
>> + if (scm_is_false_or_lisp_nil (call (pred, SCM_CAR (walk))))
>> prev = SCM_CDRLOC (walk);
>> else
>> *prev = SCM_CDR (walk);
>> @@ -1987,7 +1996,7 @@ SCM_DEFINE (scm_srfi1_span, "span", 2, 0, 0,
>> for ( ; scm_is_pair (lst); lst = SCM_CDR (lst))
>> {
>> SCM elem = SCM_CAR (lst);
>> - if (scm_is_false (pred_tramp (pred, elem)))
>> + if (scm_is_false_or_lisp_nil (pred_tramp (pred, elem)))
>> goto done;
>>
>> /* want this elem, tack it onto the end of ret */
>> @@ -2019,7 +2028,7 @@ SCM_DEFINE (scm_srfi1_span_x, "span!", 2, 0, 0,
>> p = &lst;
>> for (upto = lst; scm_is_pair (upto); upto = SCM_CDR (upto))
>> {
>> - if (scm_is_false (pred_tramp (pred, SCM_CAR (upto))))
>> + if (scm_is_false_or_lisp_nil (pred_tramp (pred, SCM_CAR (upto))))
>> goto done;
>>
>> /* want this element */
>> @@ -2147,7 +2156,7 @@ SCM_DEFINE (scm_srfi1_take_while, "take-while", 2, 0, 0,
>> for ( ; scm_is_pair (lst); lst = SCM_CDR (lst))
>> {
>> SCM elem = SCM_CAR (lst);
>> - if (scm_is_false (pred_tramp (pred, elem)))
>> + if (scm_is_false_or_lisp_nil (pred_tramp (pred, elem)))
>> goto done;
>>
>> /* want this elem, tack it onto the end of ret */
>> @@ -2178,7 +2187,7 @@ SCM_DEFINE (scm_srfi1_take_while_x, "take-while!", 2, 0, 0,
>> p = &lst;
>> for (upto = lst; scm_is_pair (upto); upto = SCM_CDR (upto))
>> {
>> - if (scm_is_false (pred_tramp (pred, SCM_CAR (upto))))
>> + if (scm_is_false_or_lisp_nil (pred_tramp (pred, SCM_CAR (upto))))
>> goto done;
>>
>> /* want this element */
>>
>> diff --git a/libguile/discouraged.h b/libguile/discouraged.h
>> index 1be05f0..0411069 100644
>> --- a/libguile/discouraged.h
>> +++ b/libguile/discouraged.h
>> @@ -54,6 +54,9 @@
>>
>> /* SCM_BOOL_NOT returns the other boolean.
>> * The order of ^s here is important for Borland C++ (!?!?!)
>> + *
>> + * XXX Should this handle %nil properly, and thus be
>> + * defined as (scm_from_bool (scm_is_false_or_lisp_nil (x))) ?
>> */
>> #define SCM_BOOL_NOT(x) (SCM_PACK (SCM_UNPACK (x) \
>> ^ (SCM_UNPACK (SCM_BOOL_T) \
>> diff --git a/libguile/goops.c b/libguile/goops.c
>> index 1548472..b6234a6 100644
>> --- a/libguile/goops.c
>> +++ b/libguile/goops.c
>> @@ -190,11 +190,12 @@ SCM_DEFINE (scm_class_of, "class-of", 1, 0, 0,
>> return scm_class_integer;
>>
>> case scm_tc3_imm24:
>> + /* XXX What should be done with SCM_ELISP_NIL? */
>> if (SCM_CHARP (x))
>> return scm_class_char;
>> - else if (scm_is_bool (x))
>> + else if (scm_is_bool_and_not_lisp_nil (x))
>> return scm_class_boolean;
>> - else if (scm_is_null (x))
>> + else if (scm_is_null_and_not_lisp_nil (x))
>> return scm_class_null;
>> else
>> return scm_class_unknown;
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH] %nil-handling optimization and fixes v1
2009-07-23 21:38 ` Andy Wingo
2009-07-30 22:05 ` Neil Jerram
@ 2009-08-30 9:18 ` Neil Jerram
2009-08-30 18:01 ` Mark H Weaver
2 siblings, 0 replies; 11+ messages in thread
From: Neil Jerram @ 2009-08-30 9:18 UTC (permalink / raw)
To: Andy Wingo; +Cc: Mark H Weaver, guile-devel
Andy Wingo <wingo@pobox.com> writes:
>> scm_is_false_assume_not_lisp_nil scm_is_true_assume_not_lisp_nil
>> scm_is_false_and_not_lisp_nil scm_is_true_or_lisp_nil
>> scm_is_false_or_lisp_nil scm_is_true_and_not_lisp_nil
>>
>> scm_is_lisp_false scm_is_lisp_true
>>
>> scm_is_null_assume_not_lisp_nil
>> scm_is_null_and_not_lisp_nil
>> scm_is_null_or_lisp_nil
>>
>> scm_is_bool_and_not_lisp_nil
>> scm_is_bool_or_lisp_nil
>
> These are terrible names. But they seem to be the best names for the
> concepts we're trying to express. I don't understand all of them yet,
> will wait for a review -- unless Neil takes care of that before I do ;-)
I actually feel quite comfortable with them, now that I've read the
patch carefully. Mark's comments above the macro definitions seem
helpful and sufficient to me.
Regards,
Neil
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH] %nil-handling optimization and fixes v1
2009-08-28 7:08 ` Neil Jerram
@ 2009-08-30 13:58 ` Neil Jerram
0 siblings, 0 replies; 11+ messages in thread
From: Neil Jerram @ 2009-08-30 13:58 UTC (permalink / raw)
To: Mark H Weaver; +Cc: guile-devel
Neil Jerram <neil@ossau.uklinux.net> writes:
> because if we agreed this, some of the changes would be needed, or
> wouldn't be needed.
:-)
I think I meant to say "would be different, or wouldn't be needed".
Neil
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH] %nil-handling optimization and fixes v1
2009-07-23 21:38 ` Andy Wingo
2009-07-30 22:05 ` Neil Jerram
2009-08-30 9:18 ` Neil Jerram
@ 2009-08-30 18:01 ` Mark H Weaver
2009-09-01 22:09 ` Neil Jerram
2 siblings, 1 reply; 11+ messages in thread
From: Mark H Weaver @ 2009-08-30 18:01 UTC (permalink / raw)
To: Andy Wingo; +Cc: guile-devel
I wrote:
> > I added the following macros, whose names explicitly state how %nil
> > should be handled. See the comments in the patch for more information
> > about these.
> >
> > scm_is_false_assume_not_lisp_nil scm_is_true_assume_not_lisp_nil
> > scm_is_false_and_not_lisp_nil scm_is_true_or_lisp_nil
> > scm_is_false_or_lisp_nil scm_is_true_and_not_lisp_nil
> >
> > scm_is_lisp_false scm_is_lisp_true
> >
> > scm_is_null_assume_not_lisp_nil
> > scm_is_null_and_not_lisp_nil
> > scm_is_null_or_lisp_nil
> >
> > scm_is_bool_and_not_lisp_nil
> > scm_is_bool_or_lisp_nil
Andy wrote:
> These are terrible names. But they seem to be the best names for the
> concepts we're trying to express. I don't understand all of them yet,
> will wait for a review -- unless Neil takes care of that before I do ;-)
I agree that the names are uncomfortably long. We could shorten them
without much loss of clarity by replacing "lisp_nil" with "nil" and
"and_not" with "not", yielding:
scm_is_false_assume_not_nil scm_is_true_assume_not_nil
scm_is_false_not_nil scm_is_true_or_nil
scm_is_false_or_nil scm_is_true_not_nil
scm_is_lisp_false scm_is_lisp_true
scm_is_null_assume_not_nil
scm_is_null_not_nil
scm_is_null_or_nil
scm_is_bool_not_nil
scm_is_bool_or_nil
I can still do this if y'all would prefer the shorter names. However,
if we've all agreed that scm_is_null/false/true will treat %nil as
both false and null (have we?), the longer names will rarely be
needed.
Are there any remaining objections to mapping scm_is_false/true/null
as follows?
scm_is_null --> scm_is_null_or_lisp_nil
scm_is_false --> scm_is_false_or_lisp_nil
scm_is_true --> scm_is_true_and_not_lisp_nil
Mark
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH] %nil-handling optimization and fixes v1
2009-08-30 18:01 ` Mark H Weaver
@ 2009-09-01 22:09 ` Neil Jerram
2009-09-02 16:00 ` Mark H Weaver
0 siblings, 1 reply; 11+ messages in thread
From: Neil Jerram @ 2009-09-01 22:09 UTC (permalink / raw)
To: Mark H Weaver; +Cc: Andy Wingo, guile-devel
Mark H Weaver <mhw@netris.org> writes:
> I agree that the names are uncomfortably long. We could shorten them
> without much loss of clarity by replacing "lisp_nil" with "nil" and
> "and_not" with "not", yielding:
>
> scm_is_false_assume_not_nil scm_is_true_assume_not_nil
> scm_is_false_not_nil scm_is_true_or_nil
> scm_is_false_or_nil scm_is_true_not_nil
>
> scm_is_lisp_false scm_is_lisp_true
>
> scm_is_null_assume_not_nil
> scm_is_null_not_nil
> scm_is_null_or_nil
>
> scm_is_bool_not_nil
> scm_is_bool_or_nil
>
> I can still do this if y'all would prefer the shorter names.
FWIW, dropping "lisp_" looks OK, but I'm not sure about dropping
"and_". "scm_is_false_not_nil" feels notably harder to understand
than "scm_is_false_and_not_nil".
> Are there any remaining objections to mapping scm_is_false/true/null
> as follows?
>
> scm_is_null --> scm_is_null_or_lisp_nil
> scm_is_false --> scm_is_false_or_lisp_nil
> scm_is_true --> scm_is_true_and_not_lisp_nil
(Not from me - but I assume you're checking with others...)
Neil
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH] %nil-handling optimization and fixes v1
2009-09-01 22:09 ` Neil Jerram
@ 2009-09-02 16:00 ` Mark H Weaver
0 siblings, 0 replies; 11+ messages in thread
From: Mark H Weaver @ 2009-09-02 16:00 UTC (permalink / raw)
To: Neil Jerram; +Cc: Andy Wingo, guile-devel
Neil Jerram wrote:
> FWIW, dropping "lisp_" looks OK, but I'm not sure about dropping
> "and_". "scm_is_false_not_nil" feels notably harder to understand
> than "scm_is_false_and_not_nil".
Yes, I see your point, and I agree.
Mark
^ permalink raw reply [flat|nested] 11+ messages in thread
end of thread, other threads:[~2009-09-02 16:00 UTC | newest]
Thread overview: 11+ messages (download: mbox.gz follow: Atom feed
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2009-07-09 16:11 [PATCH] %nil-handling optimization and fixes v1 Mark H Weaver
2009-07-23 21:38 ` Andy Wingo
2009-07-30 22:05 ` Neil Jerram
2009-08-30 9:18 ` Neil Jerram
2009-08-30 18:01 ` Mark H Weaver
2009-09-01 22:09 ` Neil Jerram
2009-09-02 16:00 ` Mark H Weaver
2009-08-28 7:08 ` Neil Jerram
2009-08-28 7:11 ` Neil Jerram
2009-08-28 7:08 ` Neil Jerram
2009-08-30 13:58 ` Neil Jerram
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