diff --git a/libguile/ChangeLog b/libguile/ChangeLog
index cd72ef097..f28ecbbb0 100644
--- a/libguile/ChangeLog
+++ b/libguile/ChangeLog
@@ -1,3 +1,98 @@
+2002-01-22  Neil Jerram  <neil@ossau.uklinux.net>
+	
+	Other changes unrelated to Elisp...
+	
+	* eval.c (scm_m_if): Use s_if rather than repeating string literal
+	"if".
+	(comments): Fix a few typos.
+	(scm_for_each): Add parentheses around oddly unparenthesized
+	if/while conditions.
+
+	* read.c (scm_read_opts): Add full stop at end of doc for
+	`keywords' option.
+
+	* script.c (scm_compile_shell_switches): Use scm_str2symbol
+	instead of gh_symbol2scm.
+
+	* srcprop.h (SRCPROPBRK): Return C type rather than SCM.
+	(SRCBRKP): Use SRCPROPBRK rather than duplicating its logic.
+
+	* srcprop.c (scm_srcprops_to_plist, scm_source_property): Change
+	SRCPROPBRK (x) to SCM_BOOL (SRCPROPBRK (x)).
+
+	First batch of changes for Elisp support...
+
+	* alist.c, async.c, boolean.c, dynl.c, eval.c, filesys.c,
+	fluids.c, list.c, load.c, options.c, posix.c, print.c, sort.c,
+	throw.c, vectors.c, weaks.c: Add #include for lang.h.
+
+	* eval.c, eval.h, init.c, lang.c, lang.h: Use SCM_ENABLE_ELISP to
+	conditionalize compilation and initialization of Elisp support
+	function.
+	
+	* alist.c (scm_assq, scm_assv, scm_assoc), async.c
+	(scm_asyncs_pending, scm_run_asyncs, noop), backtrace.c
+	(scm_set_print_params_x), dynl.c (scm_make_argv_from_stringlist),
+	filesys.c (fill_select_type, retrieve_select_type), fluids.c
+	(scm_swap_fluids, scm_swap_fluids_reverse), list.c (scm_null_p,
+	scm_ilength, scm_append_x, scm_last_pair, scm_reverse,
+	scm_reverse_x, scm_list_ref, scm_list_set_x, scm_list_cdr_set_x,
+	scm_c_memq, scm_memv), load.c (scm_search_path), options.c
+	(change_option_setting, scm_options), posix.c (environ_list_to_c),
+	print.c (scm_iprlist), throw.c (scm_exit_status), vectors.c
+	(scm_vector), weaks.c (scm_weak_vector): Use SCM_NULL_OR_NIL_P
+	instead of SCM_NULLP.
+
+	* boolean.c (scm_not): Use `SCM_FALSEP || SCM_NILP' instead of
+	just SCM_FALSEP.
+	
+	* boolean.c (scm_boolean_p): Use `SCM_BOOLP || SCM_NILP' instead
+	of just SCM_BOOLP.
+
+	* eval.c (scm_lisp_nil, scm_lisp_t, s_nil_ify, scm_m_nil_ify,
+	s_t_ify, scm_m_t_ify, s_0_cond, scm_m_0_cond, s_0_ify,
+	scm_m_0_ify, s_1_ify, scm_m_1_ify): Removed.
+	(scm_m_atfop): Support function aliasing.  Support both function
+	args, which need transformation, and macro args, which do not.
+	Add explanatory comments.
+	(SCM_CEVAL): In switch cases for SCM_IM_AND, SCM_IM_COND,
+	SCM_IM_DO, SCM_IM_IF and SCM_IM_OR, add `|| SCM_NILP' to existing
+	checks for SCM_FALSEP.  In switch case for SCM_IM_NIL_COND, use
+	SCM_NULLP || SCM_NILP instead of checks against (removed)
+	scm_lisp_nil.  Removed switch cases for SCM_IM_NIL_IFY,
+	SCM_IM_T_IFY, SCM_IM_0_COND, SCM_IM_0_IFY, SCM_IM_1_IFY.
+
+	* lang.c (scm_nil_cons, scm_nil_car, scm_nil_cdr, scm_null,
+	scm_m_while, scm_nil_eq): Commented out; I don't think we need
+	these, but I don't want to remove them yet, just in case.
+	(scm_init_lang): Define `%nil' variable on Scheme level to hold
+	Elisp nil value.
+
+	* lang.h (SCM_NILP): Test against Elisp nil value instead of
+	against (removed) scm_lisp_nil.
+	(SCM_NILNULLP, SCM_NIL2EOL, SCM_EOL2NIL): Commented out.
+	(SCM_NULL_OR_NIL_P): New.
+
+	* list.c (scm_append): Use SCM_VALIDATE_NULL_OR_NIL instead of
+	SCM_VALIDATE_NULL.
+
+	* print.c (scm_isymnames): Fix comment.  Remove #@nil-ify,
+	#@t-ify, #@0-cond, #@0-ify, #@1-ify.  Add #nil (for SCM_ELISP_NIL
+	value).
+
+	* sort.c (scm_sorted_p, scm_merge, scm_merge_list_x, scm_merge_x,
+	scm_sort_x, scm_sort, scm_stable_sort_x, scm_stable_sort): Use
+	SCM_NULL_OR_NIL_P instead of SCM_NULLP.  In constructions like `if
+	(SCM_NULLP (x)) return SCM_EOL;', return x rather than SCM_EOL.
+
+	* tags.h (SCM_IM_NIL_IFY, SCM_IM_T_IFY, SCM_IM_0_COND,
+	SCM_IM_0_IFY, SCM_IM_1_IFY): Removed.
+	(SCM_IM_BIND, SCM_IM_DELAY, SCM_IM_CALL_WITH_VALUES, SCM_UNBOUND):
+	Numbering shifted down accordingly.
+	(SCM_ELISP_NIL): New IFLAG.
+
+	* validate.h (SCM_VALIDATE_NULL_OR_NIL): New.
+	
 2002-01-10  Dirk Herrmann  <D.Herrmann@tu-bs.de>
 
 	* eval.c:  Removed outdated references to "everr".  Improved some
diff --git a/libguile/alist.c b/libguile/alist.c
index 2dd6057b4..a3cdde604 100644
--- a/libguile/alist.c
+++ b/libguile/alist.c
@@ -44,6 +44,7 @@
 #include "libguile/_scm.h"
 #include "libguile/eq.h"
 #include "libguile/list.h"
+#include "libguile/lang.h"
 
 #include "libguile/validate.h"
 #include "libguile/alist.h"
@@ -144,7 +145,7 @@ SCM_DEFINE (scm_assq, "assq", 2, 0, 0,
       if (SCM_EQ_P (SCM_CAR (tmp), key))
 	return tmp;
     }
-  SCM_ASSERT_TYPE (SCM_NULLP (ls), alist, SCM_ARG2, FUNC_NAME,
+  SCM_ASSERT_TYPE (SCM_NULL_OR_NIL_P (ls), alist, SCM_ARG2, FUNC_NAME,
 		   "association list");
   return SCM_BOOL_F;
 }
@@ -165,7 +166,7 @@ SCM_DEFINE (scm_assv, "assv", 2, 0, 0,
       if (SCM_NFALSEP (scm_eqv_p (SCM_CAR (tmp), key)))
 	return tmp;
     }
-  SCM_ASSERT_TYPE (SCM_NULLP (ls), alist, SCM_ARG2, FUNC_NAME,
+  SCM_ASSERT_TYPE (SCM_NULL_OR_NIL_P (ls), alist, SCM_ARG2, FUNC_NAME,
 		   "association list");
   return SCM_BOOL_F;
 }
@@ -186,7 +187,7 @@ SCM_DEFINE (scm_assoc, "assoc", 2, 0, 0,
       if (SCM_NFALSEP (scm_equal_p (SCM_CAR (tmp), key)))
 	return tmp;
     }
-  SCM_ASSERT_TYPE (SCM_NULLP (ls), alist, SCM_ARG2, FUNC_NAME,
+  SCM_ASSERT_TYPE (SCM_NULL_OR_NIL_P (ls), alist, SCM_ARG2, FUNC_NAME,
 		   "association list");
   return SCM_BOOL_F;
 }
diff --git a/libguile/async.c b/libguile/async.c
index 5d06c1f77..e3b7d33f3 100644
--- a/libguile/async.c
+++ b/libguile/async.c
@@ -48,6 +48,7 @@
 #include "libguile/throw.h"
 #include "libguile/root.h"
 #include "libguile/smob.h"
+#include "libguile/lang.h"
 
 #include "libguile/validate.h"
 #include "libguile/async.h"
@@ -128,7 +129,7 @@ scm_asyncs_pending ()
 {
   SCM pos;
   pos = scm_asyncs;
-  while (!SCM_NULLP (pos))
+  while (!SCM_NULL_OR_NIL_P (pos))
     {
       SCM a = SCM_CAR (pos);
       if (ASYNC_GOT_IT (a))
@@ -356,7 +357,7 @@ SCM_DEFINE (scm_run_asyncs, "run-asyncs", 1, 0, 0,
 #else
   scm_asyncs_pending_p = 0;
 #endif
-  while (! SCM_NULLP (list_of_a))
+  while (! SCM_NULL_OR_NIL_P (list_of_a))
     {
       SCM a;
       SCM_VALIDATE_CONS (1, list_of_a);
@@ -385,7 +386,7 @@ SCM_DEFINE (scm_noop, "noop", 0, 0, 1,
 #define FUNC_NAME s_scm_noop
 {
   SCM_VALIDATE_REST_ARGUMENT (args);
-  return (SCM_NULLP (args) ? SCM_BOOL_F : SCM_CAR (args));
+  return (SCM_NULL_OR_NIL_P (args) ? SCM_BOOL_F : SCM_CAR (args));
 }
 #undef FUNC_NAME
 
diff --git a/libguile/backtrace.c b/libguile/backtrace.c
index 803f5aaaa..290627fbb 100644
--- a/libguile/backtrace.c
+++ b/libguile/backtrace.c
@@ -302,7 +302,7 @@ SCM_DEFINE (scm_set_print_params_x, "set-print-params!", 1, 0, 0,
   print_params_t *new_params;
 
   SCM_VALIDATE_NONEMPTYLIST_COPYLEN (2, params, n);
-  for (ls = params; !SCM_NULLP (ls); ls = SCM_CDR (ls))
+  for (ls = params; !SCM_NULL_OR_NIL_P (ls); ls = SCM_CDR (ls))
     SCM_ASSERT (scm_ilength (SCM_CAR (params)) == 2
 		&& SCM_INUMP (SCM_CAAR (ls))
 		&& SCM_INUM (SCM_CAAR (ls)) >= 0
diff --git a/libguile/boolean.c b/libguile/boolean.c
index da56aab54..402fce55d 100644
--- a/libguile/boolean.c
+++ b/libguile/boolean.c
@@ -46,6 +46,7 @@
 
 #include "libguile/validate.h"
 #include "libguile/boolean.h"
+#include "libguile/lang.h"
 
 
 
@@ -54,7 +55,7 @@ SCM_DEFINE (scm_not, "not", 1, 0, 0,
             "Return @code{#t} iff @var{x} is @code{#f}, else return @code{#f}.")
 #define FUNC_NAME s_scm_not
 {
-  return SCM_BOOL(SCM_FALSEP(x));
+  return SCM_BOOL(SCM_FALSEP (x) || SCM_NILP (x));
 }
 #undef FUNC_NAME
 
@@ -64,7 +65,7 @@ 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_BOOL (SCM_BOOLP (obj));
+  return SCM_BOOL (SCM_BOOLP (obj) || SCM_NILP (obj));
 }
 #undef FUNC_NAME
 
diff --git a/libguile/dynl.c b/libguile/dynl.c
index 136595780..d920b2d7a 100644
--- a/libguile/dynl.c
+++ b/libguile/dynl.c
@@ -72,6 +72,7 @@ maybe_drag_in_eprintf ()
 #include "libguile/ports.h"
 #include "libguile/strings.h"
 #include "libguile/deprecation.h"
+#include "libguile/lang.h"
 #include "libguile/validate.h"
 
 /* Create a new C argv array from a scheme list of strings. */
@@ -97,7 +98,7 @@ scm_make_argv_from_stringlist (SCM args,int *argcp,const char *subr,int argn)
   argc = scm_ilength (args);
   SCM_ASSERT (argc >= 0, args, argn, subr);
   argv = (char **) scm_must_malloc ((argc + 1) * sizeof (char *), subr);
-  for (i = 0; !SCM_NULLP (args); args = SCM_CDR (args), ++i) {
+  for (i = 0; !SCM_NULL_OR_NIL_P (args); args = SCM_CDR (args), ++i) {
     SCM arg = SCM_CAR (args);
     size_t len;
     char *dst;
diff --git a/libguile/eval.c b/libguile/eval.c
index 4138456d7..2fff70468 100644
--- a/libguile/eval.c
+++ b/libguile/eval.c
@@ -100,6 +100,7 @@ char *alloca ();
 
 #include "libguile/validate.h"
 #include "libguile/eval.h"
+#include "libguile/lang.h"
 
 
 
@@ -537,7 +538,7 @@ SCM
 scm_m_if (SCM xorig, SCM env SCM_UNUSED)
 {
   long len = scm_ilength (SCM_CDR (xorig));
-  SCM_ASSYNT (len >= 2 && len <= 3, scm_s_expression, "if");
+  SCM_ASSYNT (len >= 2 && len <= 3, scm_s_expression, s_if);
   return scm_cons (SCM_IM_IF, SCM_CDR (xorig));
 }
 
@@ -1073,10 +1074,7 @@ scm_m_cont (SCM xorig, SCM env SCM_UNUSED)
   return scm_cons (SCM_IM_CONT, SCM_CDR (xorig));
 }
 
-/* Multi-language support */
-
-SCM_GLOBAL_SYMBOL (scm_lisp_nil, "nil");
-SCM_GLOBAL_SYMBOL (scm_lisp_t, "t");
+#ifdef SCM_ENABLE_ELISP
 
 SCM_SYNTAX (s_nil_cond, "nil-cond", scm_makmmacro, scm_m_nil_cond);
 
@@ -1088,52 +1086,6 @@ scm_m_nil_cond (SCM xorig, SCM env SCM_UNUSED)
   return scm_cons (SCM_IM_NIL_COND, SCM_CDR (xorig));
 }
 
-SCM_SYNTAX (s_nil_ify, "nil-ify", scm_makmmacro, scm_m_nil_ify);
-
-SCM
-scm_m_nil_ify (SCM xorig, SCM env SCM_UNUSED)
-{
-  SCM_ASSYNT (scm_ilength (SCM_CDR (xorig)) == 1, scm_s_expression, "nil-ify");
-  return scm_cons (SCM_IM_NIL_IFY, SCM_CDR (xorig));
-}
-
-SCM_SYNTAX (s_t_ify, "t-ify", scm_makmmacro, scm_m_t_ify);
-
-SCM
-scm_m_t_ify (SCM xorig, SCM env SCM_UNUSED)
-{
-  SCM_ASSYNT (scm_ilength (SCM_CDR (xorig)) == 1, scm_s_expression, "t-ify");
-  return scm_cons (SCM_IM_T_IFY, SCM_CDR (xorig));
-}
-
-SCM_SYNTAX (s_0_cond, "0-cond", scm_makmmacro, scm_m_0_cond);
-
-SCM
-scm_m_0_cond (SCM xorig, SCM env SCM_UNUSED)
-{
-  long len = scm_ilength (SCM_CDR (xorig));
-  SCM_ASSYNT (len >= 1 && (len & 1) == 1, scm_s_expression, "0-cond");
-  return scm_cons (SCM_IM_0_COND, SCM_CDR (xorig));
-}
-
-SCM_SYNTAX (s_0_ify, "0-ify", scm_makmmacro, scm_m_0_ify);
-
-SCM
-scm_m_0_ify (SCM xorig, SCM env SCM_UNUSED)
-{
-  SCM_ASSYNT (scm_ilength (SCM_CDR (xorig)) == 1, scm_s_expression, "0-ify");
-  return scm_cons (SCM_IM_0_IFY, SCM_CDR (xorig));
-}
-
-SCM_SYNTAX (s_1_ify, "1-ify", scm_makmmacro, scm_m_1_ify);
-
-SCM
-scm_m_1_ify (SCM xorig, SCM env SCM_UNUSED)
-{
-  SCM_ASSYNT (scm_ilength (SCM_CDR (xorig)) == 1, scm_s_expression, "1-ify");
-  return scm_cons (SCM_IM_1_IFY, SCM_CDR (xorig));
-}
-
 SCM_SYNTAX (s_atfop, "@fop", scm_makmmacro, scm_m_atfop);
 
 SCM
@@ -1142,12 +1094,45 @@ scm_m_atfop (SCM xorig, SCM env SCM_UNUSED)
   SCM x = SCM_CDR (xorig), var;
   SCM_ASSYNT (scm_ilength (x) >= 1, scm_s_expression, "@fop");
   var = scm_symbol_fref (SCM_CAR (x));
+  /* Passing the symbol name as the `subr' arg here isn't really
+     right, but without it it can be very difficult to work out from
+     the error message which function definition was missing.  In any
+     case, we shouldn't really use SCM_ASSYNT here at all, but instead
+     something equivalent to (signal void-function (list SYM)) in
+     Elisp. */
   SCM_ASSYNT (SCM_VARIABLEP (var),
-	      "Symbol's function definition is void", NULL);
+	      "Symbol's function definition is void",
+	      SCM_SYMBOL_CHARS (SCM_CAR (x)));
+  /* Support `defalias'. */
+  while (SCM_SYMBOLP (SCM_VARIABLE_REF (var)))
+    {
+      var = scm_symbol_fref (SCM_VARIABLE_REF (var));
+      SCM_ASSYNT (SCM_VARIABLEP (var),
+		  "Symbol's function definition is void",
+		  SCM_SYMBOL_CHARS (SCM_CAR (x)));
+    }
+  /* Use `var' here rather than `SCM_VARIABLE_REF (var)' because the
+     former allows for automatically picking up redefinitions of the
+     corresponding symbol. */
   SCM_SETCAR (x, var);
+  /* If the variable contains a procedure, leave the
+     `transformer-macro' in place so that the procedure's arguments
+     get properly transformed, and change the initial @fop to
+     SCM_IM_APPLY. */
+  if (!SCM_MACROP (SCM_VARIABLE_REF (var)))
+    {
+      SCM_SETCAR (xorig, SCM_IM_APPLY);
+      return xorig;
+    }
+  /* Otherwise (the variable contains a macro), the arguments should
+     not be transformed, so cut the `transformer-macro' out and return
+     the resulting expression starting with the variable. */
+  SCM_SETCDR (x, SCM_CDADR (x));
   return x;
 }
 
+#endif /* SCM_ENABLE_ELISP */
+
 /* (@bind ((var exp) ...) body ...)
 
   This will assign the values of the `exp's to the global variables
@@ -1158,7 +1143,7 @@ scm_m_atfop (SCM xorig, SCM env SCM_UNUSED)
   error when a symbol appears more than once among the `var's.
   All `exp's are evaluated before any `var' is set.
 
-  This of this as `let' for dynamic scope.
+  Think of this as `let' for dynamic scope.
 
   It is memoized into (#@bind ((var ...) . (reversed-val ...)) body ...).
 
@@ -1325,7 +1310,7 @@ scm_macroexp (SCM x, SCM env)
  * generating the source for a stackframe in a backtrace, and in
  * display_expression.
  *
- * Unmemoizing is not a realiable process.  You can not in general
+ * Unmemoizing is not a reliable process.  You cannot in general
  * expect to get the original source back.
  *
  * However, GOOPS currently relies on this for method compilation.
@@ -2018,7 +2003,7 @@ dispatch:
       x = SCM_CDR (x);
       while (!SCM_NULLP (SCM_CDR (x)))
 	{
-	  if (SCM_FALSEP (EVALCAR (x, env)))
+	  if (SCM_FALSEP (t.arg1 = EVALCAR (x, env)) || SCM_NILP (t.arg1))
 	    RETURN (SCM_BOOL_F);
 	  else
 	    x = SCM_CDR (x);
@@ -2129,7 +2114,7 @@ dispatch:
 	      goto begin;
 	    }
 	  t.arg1 = EVALCAR (proc, env);
-	  if (!SCM_FALSEP (t.arg1))
+	  if (!SCM_FALSEP (t.arg1) && !SCM_NILP (t.arg1))
 	    {
 	      x = SCM_CDR (proc);
 	      if (SCM_NULLP (x))
@@ -2164,7 +2149,8 @@ dispatch:
 	}
       env = EXTEND_ENV (SCM_CAR (x), t.arg1, env);
       x = SCM_CDDR (x);
-      while (proc = SCM_CAR (x), SCM_FALSEP (EVALCAR (proc, env)))
+      while (proc = SCM_CAR (x),
+	     SCM_FALSEP (t.arg1 = EVALCAR (proc, env)) || SCM_NILP (t.arg1))
 	{
 	  for (proc = SCM_CADR (x); SCM_NIMP (proc); proc = SCM_CDR (proc))
 	    {
@@ -2186,7 +2172,7 @@ dispatch:
 
     case SCM_BIT8(SCM_IM_IF):
       x = SCM_CDR (x);
-      if (!SCM_FALSEP (EVALCAR (x, env)))
+      if (!SCM_FALSEP (t.arg1 = EVALCAR (x, env)) && !SCM_NILP (t.arg1))
 	x = SCM_CDR (x);
       else if (SCM_IMP (x = SCM_CDDR (x)))
 	RETURN (SCM_UNSPECIFIED);
@@ -2249,7 +2235,7 @@ dispatch:
       while (!SCM_NULLP (SCM_CDR (x)))
 	{
 	  SCM val = EVALCAR (x, env);
-	  if (!SCM_FALSEP (val))
+	  if (!SCM_FALSEP (val) && !SCM_NILP (val))
 	    RETURN (val);
 	  else
 	    x = SCM_CDR (x);
@@ -2477,13 +2463,16 @@ dispatch:
 	  SCM_STRUCT_DATA (t.arg1) [SCM_INUM (SCM_CAR (x))]
 	    = SCM_UNPACK (EVALCAR (proc, env));
 	  RETURN (SCM_UNSPECIFIED);
+
+#ifdef SCM_ENABLE_ELISP
 	  
 	case (SCM_ISYMNUM (SCM_IM_NIL_COND)):
 	  proc = SCM_CDR (x);
 	  while (SCM_NIMP (x = SCM_CDR (proc)))
 	    {
 	      if (!(SCM_FALSEP (t.arg1 = EVALCAR (proc, env))
-		    || SCM_EQ_P (t.arg1, scm_lisp_nil)))
+		    || SCM_NILP (t.arg1)
+		    || SCM_NULLP (t.arg1)))
 		{
 		  if (SCM_EQ_P (SCM_CAR (x), SCM_UNSPECIFIED))
 		    RETURN (t.arg1);
@@ -2496,45 +2485,7 @@ dispatch:
 	  PREP_APPLY (SCM_UNDEFINED, SCM_EOL);
 	  goto carloop;
 
-	case (SCM_ISYMNUM (SCM_IM_NIL_IFY)):
-	  x = SCM_CDR (x);
-	  RETURN ((SCM_FALSEP (proc = EVALCAR (x, env)) || SCM_NULLP (proc))
-		  ? scm_lisp_nil
-		  : proc);
-	    
-	case (SCM_ISYMNUM (SCM_IM_T_IFY)):
-	  x = SCM_CDR (x);
-	  RETURN (!SCM_FALSEP (EVALCAR (x, env)) ? scm_lisp_t : scm_lisp_nil);
-	    
-	case (SCM_ISYMNUM (SCM_IM_0_COND)):
-	  proc = SCM_CDR (x);
-	  while (SCM_NIMP (x = SCM_CDR (proc)))
-	    {
-	      if (!(SCM_FALSEP (t.arg1 = EVALCAR (proc, env))
-		    || SCM_EQ_P (t.arg1, SCM_INUM0)))
-		{
-		  if (SCM_EQ_P (SCM_CAR (x), SCM_UNSPECIFIED))
-		    RETURN (t.arg1);
-		  PREP_APPLY (SCM_UNDEFINED, SCM_EOL);
-		  goto carloop;
-		}
-	      proc = SCM_CDR (x);
-	    }
-	  x = proc;
-	  PREP_APPLY (SCM_UNDEFINED, SCM_EOL);
-	  goto carloop;
-
-	case (SCM_ISYMNUM (SCM_IM_0_IFY)):
-	  x = SCM_CDR (x);
-	  RETURN (SCM_FALSEP (proc = EVALCAR (x, env))
-		  ? SCM_INUM0
-		  : proc);
-	    
-	case (SCM_ISYMNUM (SCM_IM_1_IFY)):
-	  x = SCM_CDR (x);
-	  RETURN (!SCM_FALSEP (EVALCAR (x, env))
-		  ? SCM_MAKINUM (1)
-		  : SCM_INUM0);
+#endif /* SCM_ENABLE_ELISP */
 
 	case (SCM_ISYMNUM (SCM_IM_BIND)):
 	  {
@@ -2568,7 +2519,7 @@ dispatch:
 
 	    RETURN (proc);
 	  }
-	  
+
 	case (SCM_ISYMNUM (SCM_IM_CALL_WITH_VALUES)):
 	  {
 	    proc = SCM_CDR (x);
@@ -3388,7 +3339,11 @@ SCM_DEFINE (scm_nconc2last, "apply:nconc2last", 1, 0, 0,
   SCM *lloc;
   SCM_VALIDATE_NONEMPTYLIST (1,lst);
   lloc = &lst;
-  while (!SCM_NULLP (SCM_CDR (*lloc)))
+  while (!SCM_NULLP (SCM_CDR (*lloc))) /* Perhaps should be
+                                          SCM_NULL_OR_NIL_P, but not
+                                          needed in 99.99% of cases,
+                                          and it could seriously hurt
+                                          performance. - Neil */
     lloc = SCM_CDRLOC (*lloc);
   SCM_ASSERT (scm_ilength (SCM_CAR (*lloc)) >= 0, lst, SCM_ARG1, FUNC_NAME);
   *lloc = SCM_CAR (*lloc);
@@ -3846,9 +3801,9 @@ scm_for_each (SCM proc, SCM arg1, SCM args)
   SCM_GASSERTn (len >= 0, g_for_each, scm_cons2 (proc, arg1, args),
 		SCM_ARG2, s_for_each);
   SCM_VALIDATE_REST_ARGUMENT (args);
-  if SCM_NULLP (args)
+  if (SCM_NULLP (args))
     {
-      while SCM_NIMP (arg1)
+      while (SCM_NIMP (arg1))
 	{
 	  scm_apply (proc, SCM_CAR (arg1), scm_listofnull);
 	  arg1 = SCM_CDR (arg1);
@@ -3865,8 +3820,8 @@ scm_for_each (SCM proc, SCM arg1, SCM args)
       arg1 = SCM_EOL;
       for (i = SCM_VECTOR_LENGTH (args) - 1; i >= 0; i--)
 	{
-	  if SCM_IMP
-	    (ve[i]) return SCM_UNSPECIFIED;
+	  if (SCM_IMP (ve[i]))
+	    return SCM_UNSPECIFIED;
 	  arg1 = scm_cons (SCM_CAR (ve[i]), arg1);
 	  ve[i] = SCM_CDR (ve[i]);
 	}
@@ -4182,9 +4137,6 @@ scm_init_eval ()
 #ifndef SCM_MAGIC_SNARFER
 #include "libguile/eval.x"
 #endif
-
-  scm_c_define ("nil", scm_lisp_nil);
-  scm_c_define ("t", scm_lisp_t);
   
   scm_add_feature ("delay");
 }
diff --git a/libguile/eval.h b/libguile/eval.h
index 27f3860db..7d76a9098 100644
--- a/libguile/eval.h
+++ b/libguile/eval.h
@@ -204,13 +204,10 @@ SCM_API SCM scm_m_letrec (SCM xorig, SCM env);
 SCM_API SCM scm_m_let (SCM xorig, SCM env);
 SCM_API SCM scm_m_apply (SCM xorig, SCM env);
 SCM_API SCM scm_m_cont (SCM xorig, SCM env);
+#ifdef SCM_ENABLE_ELISP
 SCM_API SCM scm_m_nil_cond (SCM xorig, SCM env);
-SCM_API SCM scm_m_nil_ify (SCM xorig, SCM env);
-SCM_API SCM scm_m_t_ify (SCM xorig, SCM env);
-SCM_API SCM scm_m_0_cond (SCM xorig, SCM env);
-SCM_API SCM scm_m_0_ify (SCM xorig, SCM env);
-SCM_API SCM scm_m_1_ify (SCM xorig, SCM env);
 SCM_API SCM scm_m_atfop (SCM xorig, SCM env);
+#endif /* SCM_ENABLE_ELISP */
 SCM_API SCM scm_m_atbind (SCM xorig, SCM env);
 SCM_API SCM scm_m_at_call_with_values (SCM xorig, SCM env);
 SCM_API int scm_badargsp (SCM formals, SCM args);
diff --git a/libguile/filesys.c b/libguile/filesys.c
index b8a9aadc9..862579c10 100644
--- a/libguile/filesys.c
+++ b/libguile/filesys.c
@@ -51,6 +51,7 @@
 #include "libguile/iselect.h"
 #include "libguile/strings.h"
 #include "libguile/vectors.h"
+#include "libguile/lang.h"
 
 #include "libguile/validate.h"
 #include "libguile/filesys.h"
@@ -1032,7 +1033,7 @@ fill_select_type (SELECT_TYPE *set, SCM *ports_ready, SCM list_or_vec, int pos)
     }
   else
     {
-      while (!SCM_NULLP (list_or_vec))
+      while (!SCM_NULL_OR_NIL_P (list_or_vec))
 	{
 	  int fd = set_element (set, ports_ready, SCM_CAR (list_or_vec), pos);
 
@@ -1092,7 +1093,7 @@ retrieve_select_type (SELECT_TYPE *set, SCM ports_ready, SCM list_or_vec)
   else
     {
       /* list_or_vec must be a list.  */
-      while (!SCM_NULLP (list_or_vec))
+      while (!SCM_NULL_OR_NIL_P (list_or_vec))
 	{
 	  answer_list = get_element (set, SCM_CAR (list_or_vec), answer_list);
 	  list_or_vec = SCM_CDR (list_or_vec);
diff --git a/libguile/fluids.c b/libguile/fluids.c
index 2a8ff9a1f..7901e2231 100644
--- a/libguile/fluids.c
+++ b/libguile/fluids.c
@@ -50,6 +50,7 @@
 #include "libguile/eval.h"
 #include "libguile/ports.h"
 #include "libguile/deprecation.h"
+#include "libguile/lang.h"
 
 #define INITIAL_FLUIDS 10
 #include "libguile/validate.h"
@@ -178,7 +179,7 @@ SCM_DEFINE (scm_fluid_set_x, "fluid-set!", 2, 0, 0,
 void
 scm_swap_fluids (SCM fluids, SCM vals)
 {
-  while (!SCM_NULLP (fluids))
+  while (!SCM_NULL_OR_NIL_P (fluids))
     {
       SCM fl = SCM_CAR (fluids);
       SCM old_val = scm_fluid_ref (fl);
@@ -195,7 +196,7 @@ same fluid appears multiple times in the fluids list. */
 void
 scm_swap_fluids_reverse (SCM fluids, SCM vals)
 {
-  if (!SCM_NULLP (fluids))
+  if (!SCM_NULL_OR_NIL_P (fluids))
     {
       SCM fl, old_val;
 
diff --git a/libguile/init.c b/libguile/init.c
index 5c96be4dc..b732165b4 100644
--- a/libguile/init.c
+++ b/libguile/init.c
@@ -560,7 +560,9 @@ scm_init_guile_1 (SCM_STACKITEM *base)
   scm_init_load_path ();
   scm_init_standard_ports ();  /* Requires fports */
   scm_init_dynamic_linking ();
+#ifdef SCM_ENABLE_ELISP
   scm_init_lang ();
+#endif /* SCM_ENABLE_ELISP */
   scm_init_script ();
 
   scm_init_goops ();
diff --git a/libguile/lang.c b/libguile/lang.c
index f022bee77..463cbeb5c 100644
--- a/libguile/lang.c
+++ b/libguile/lang.c
@@ -62,6 +62,9 @@
  * in all data structures.
  */
 
+#ifdef SCM_ENABLE_ELISP
+#if 0
+
 SCM_DEFINE (scm_nil_cons, "nil-cons", 2, 0, 0,
             (SCM x, SCM y),
 	    "Create a new cons cell with @var{x} as the car and @var{y} as\n"
@@ -145,17 +148,24 @@ SCM_DEFINE1 (scm_nil_eq, "nil-eq", scm_tc7_rpsubr,
 }
 #undef FUNC_NAME
 
+#endif /* 0 */
 
 
 void
 scm_init_lang ()
 {
+#if 0
 #ifndef SCM_MAGIC_SNARFER
 #include "libguile/lang.x"
 #endif
   scm_make_synt ("nil-while", scm_makacro, scm_m_while);
+#endif
+
+  scm_c_define ("%nil", SCM_ELISP_NIL);
 }
 
+#endif /* SCM_ENABLE_ELISP */
+
 /*
   Local Variables:
   c-file-style: "gnu"
diff --git a/libguile/lang.h b/libguile/lang.h
index ae10869b5..dba8a8f28 100644
--- a/libguile/lang.h
+++ b/libguile/lang.h
@@ -50,10 +50,14 @@
 
 
 
+#ifdef SCM_ENABLE_ELISP
+
+#define SCM_NILP(x) (SCM_EQ_P ((x), SCM_ELISP_NIL))
+
+#if 0
 SCM_API SCM scm_lisp_nil;
 SCM_API SCM scm_lisp_t;
 
-#define SCM_NILP(x) (SCM_EQ_P ((x), scm_lisp_nil))
 #define SCM_NILNULLP(x) (SCM_NILP (x) || SCM_NULLP (x))
 #define SCM_NIL2EOL(x, tmp) (SCM_EQ_P ((tmp = (x)), scm_lisp_nil) ? SCM_EOL : tmp)
 #define SCM_EOL2NIL(x, tmp) (SCM_NULLP (tmp = (x)) ? scm_lisp_nil : tmp)
@@ -68,7 +72,13 @@ SCM_API SCM scm_nil_cdr (SCM x);
 SCM_API SCM scm_null (SCM x);
 SCM_API SCM scm_m_while (SCM exp, SCM env);
 SCM_API SCM scm_nil_eq (SCM x, SCM y);
+#endif /* 0 */
 SCM_API void scm_init_lang (void);
+#else  /* ! SCM_ENABLE_ELISP */
+#define SCM_NILP(x) 0
+#endif /* ! SCM_ENABLE_ELISP */
+
+#define SCM_NULL_OR_NIL_P(x) (SCM_NULLP (x) || SCM_NILP (x))
 
 #endif  /* SCM_LANG_H */
 
diff --git a/libguile/list.c b/libguile/list.c
index 8d6237d20..2197a61f5 100644
--- a/libguile/list.c
+++ b/libguile/list.c
@@ -43,6 +43,7 @@
 
 #include "libguile/_scm.h"
 #include "libguile/eq.h"
+#include "libguile/lang.h"
 
 #include "libguile/validate.h"
 #include "libguile/list.h"
@@ -165,7 +166,7 @@ SCM_DEFINE (scm_null_p, "null?", 1, 0, 0,
 	    "Return @code{#t} iff @var{x} is the empty list, else @code{#f}.")
 #define FUNC_NAME s_scm_null_p
 {
-  return SCM_BOOL (SCM_NULLP (x));
+  return SCM_BOOL (SCM_NULL_OR_NIL_P (x));
 }
 #undef FUNC_NAME
 
@@ -192,11 +193,11 @@ scm_ilength(SCM sx)
   SCM hare = sx;
 
   do {
-    if (SCM_NULLP(hare)) return i;
+    if (SCM_NULL_OR_NIL_P(hare)) return i;
     if (SCM_NCONSP(hare)) return -1;
     hare = SCM_CDR(hare);
     i++;
-    if (SCM_NULLP(hare)) return i;
+    if (SCM_NULL_OR_NIL_P(hare)) return i;
     if (SCM_NCONSP(hare)) return -1;
     hare = SCM_CDR(hare);
     i++;
@@ -259,7 +260,7 @@ SCM_DEFINE (scm_append, "append", 0, 0, 1,
 	lloc = SCM_CDRLOC (*lloc);
 	arg = SCM_CDR (arg);
       }
-      SCM_VALIDATE_NULL (SCM_ARGn, arg);
+      SCM_VALIDATE_NULL_OR_NIL (SCM_ARGn, arg);
       arg = SCM_CAR (args);
       args = SCM_CDR (args);
     };
@@ -288,7 +289,7 @@ SCM_DEFINE (scm_append_x, "append!", 0, 0, 1,
       lists = SCM_CDR (lists);
       if (SCM_NULLP (lists)) {
 	return arg;
-      } else if (!SCM_NULLP (arg)) {
+      } else if (!SCM_NULL_OR_NIL_P (arg)) {
 	SCM_VALIDATE_CONS (SCM_ARG1, arg);
 	SCM_SETCDR (scm_last_pair (arg), scm_append_x (lists));
 	return arg;
@@ -308,8 +309,8 @@ SCM_DEFINE (scm_last_pair, "last-pair", 1, 0, 0,
   SCM tortoise = lst;
   SCM hare = lst;
 
-  if (SCM_NULLP (lst))
-    return SCM_EOL;
+  if (SCM_NULL_OR_NIL_P (lst))
+    return lst;
 
   SCM_VALIDATE_CONS (SCM_ARG1, lst);
   do {
@@ -340,11 +341,11 @@ SCM_DEFINE (scm_reverse, "reverse", 1, 0, 0,
   SCM hare = lst;
 
   do {
-      if (SCM_NULLP(hare)) return result;
+      if (SCM_NULL_OR_NIL_P(hare)) return result;
       SCM_ASSERT(SCM_CONSP(hare), lst, 1, FUNC_NAME);
       result = scm_cons (SCM_CAR (hare), result);
       hare = SCM_CDR (hare);
-      if (SCM_NULLP(hare)) return result;
+      if (SCM_NULL_OR_NIL_P(hare)) return result;
       SCM_ASSERT(SCM_CONSP(hare), lst, 1, FUNC_NAME);
       result = scm_cons (SCM_CAR (hare), result);
       hare = SCM_CDR (hare);
@@ -375,7 +376,7 @@ SCM_DEFINE (scm_reverse_x, "reverse!", 1, 1, 0,
   else
     SCM_VALIDATE_LIST (2, new_tail);
 
-  while (SCM_NNULLP (lst))
+  while (!SCM_NULL_OR_NIL_P (lst))
     {
       SCM old_tail = SCM_CDR (lst);
       SCM_SETCDR (lst, new_tail);
@@ -406,7 +407,7 @@ SCM_DEFINE (scm_list_ref, "list-ref", 2, 0, 0,
       lst = SCM_CDR (lst);
     }
   };
-  if (SCM_NULLP (lst))
+  if (SCM_NULL_OR_NIL_P (lst))
     SCM_OUT_OF_RANGE (2, k);
   else
     SCM_WRONG_TYPE_ARG (1, list);
@@ -431,7 +432,7 @@ SCM_DEFINE (scm_list_set_x, "list-set!", 3, 0, 0,
       lst = SCM_CDR (lst);
     }
   };
-  if (SCM_NULLP (lst))
+  if (SCM_NULL_OR_NIL_P (lst))
     SCM_OUT_OF_RANGE (2, k);
   else
     SCM_WRONG_TYPE_ARG (1, list);
@@ -479,7 +480,7 @@ SCM_DEFINE (scm_list_cdr_set_x, "list-cdr-set!", 3, 0, 0,
       lst = SCM_CDR (lst);
     }
   };
-  if (SCM_NULLP (lst))
+  if (SCM_NULL_OR_NIL_P (lst))
     SCM_OUT_OF_RANGE (2, k);
   else
     SCM_WRONG_TYPE_ARG (1, list);
@@ -555,7 +556,7 @@ SCM_DEFINE (scm_list_copy, "list-copy", 1, 0, 0,
 SCM
 scm_c_memq (SCM obj, SCM list)
 {
-  for (; !SCM_NULLP (list); list = SCM_CDR (list))
+  for (; !SCM_NULL_OR_NIL_P (list); list = SCM_CDR (list))
     {
       if (SCM_EQ_P (SCM_CAR (list), obj))
 	return list;
@@ -591,7 +592,7 @@ SCM_DEFINE (scm_memv, "memv", 2, 0, 0,
 #define FUNC_NAME s_scm_memv
 {
   SCM_VALIDATE_LIST (2, lst);
-  for (; !SCM_NULLP (lst); lst = SCM_CDR (lst))
+  for (; !SCM_NULL_OR_NIL_P (lst); lst = SCM_CDR (lst))
     {
       if (! SCM_FALSEP (scm_eqv_p (SCM_CAR (lst), x)))
 	return lst;
@@ -612,7 +613,7 @@ SCM_DEFINE (scm_member, "member", 2, 0, 0,
 #define FUNC_NAME s_scm_member
 {
   SCM_VALIDATE_LIST (2, lst);
-  for (; !SCM_NULLP (lst); lst = SCM_CDR (lst))
+  for (; !SCM_NULL_OR_NIL_P (lst); lst = SCM_CDR (lst))
     {
       if (! SCM_FALSEP (scm_equal_p (SCM_CAR (lst), x)))
 	return lst;
diff --git a/libguile/load.c b/libguile/load.c
index d26f5aca8..0c8011534 100644
--- a/libguile/load.c
+++ b/libguile/load.c
@@ -55,6 +55,7 @@
 #include "libguile/root.h"
 #include "libguile/strings.h"
 #include "libguile/modules.h"
+#include "libguile/lang.h"
 
 #include "libguile/validate.h"
 #include "libguile/load.h"
@@ -300,7 +301,7 @@ SCM_DEFINE (scm_search_path, "search-path", 2, 1, 0,
     SCM walk;
 
     max_path_len = 0;
-    for (walk = path; !SCM_NULLP (walk); walk = SCM_CDR (walk))
+    for (walk = path; !SCM_NULL_OR_NIL_P (walk); walk = SCM_CDR (walk))
       {
 	SCM elt = SCM_CAR (walk);
 	SCM_ASSERT_TYPE (SCM_STRINGP (elt), path, 1, FUNC_NAME,
@@ -338,7 +339,7 @@ SCM_DEFINE (scm_search_path, "search-path", 2, 1, 0,
     SCM walk;
 
     max_ext_len = 0;
-    for (walk = extensions; !SCM_NULLP (walk); walk = SCM_CDR (walk))
+    for (walk = extensions; !SCM_NULL_OR_NIL_P (walk); walk = SCM_CDR (walk))
       {
 	SCM elt = SCM_CAR (walk);
 	SCM_ASSERT_TYPE (SCM_STRINGP (elt), elt, 3, FUNC_NAME,
@@ -356,12 +357,12 @@ SCM_DEFINE (scm_search_path, "search-path", 2, 1, 0,
     char *buf = SCM_MUST_MALLOC (buf_size);
 
     /* This simplifies the loop below a bit.  */
-    if (SCM_NULLP (extensions))
+    if (SCM_NULL_OR_NIL_P (extensions))
       extensions = scm_listofnullstr;
 
     /* Try every path element.  At this point, we know the path is a
        proper list of strings.  */
-    for (; !SCM_NULLP (path); path = SCM_CDR (path))
+    for (; !SCM_NULL_OR_NIL_P (path); path = SCM_CDR (path))
       {
 	size_t len;
 	SCM dir = SCM_CAR (path);
@@ -377,7 +378,7 @@ SCM_DEFINE (scm_search_path, "search-path", 2, 1, 0,
 
 	/* Try every extension.  At this point, we know the extension
 	   list is a proper, nonempty list of strings.  */
-	for (exts = extensions; !SCM_NULLP (exts); exts = SCM_CDR (exts))
+	for (exts = extensions; !SCM_NULL_OR_NIL_P (exts); exts = SCM_CDR (exts))
 	  {
 	    SCM ext = SCM_CAR (exts);
 	    size_t ext_len = SCM_STRING_LENGTH (ext);
diff --git a/libguile/options.c b/libguile/options.c
index e95c12a85..731e62f79 100644
--- a/libguile/options.c
+++ b/libguile/options.c
@@ -47,6 +47,7 @@
 #include "libguile/_scm.h"
 #include "libguile/mallocs.h"
 #include "libguile/strings.h"
+#include "libguile/lang.h"
 
 #include "libguile/options.h"
 
@@ -198,7 +199,7 @@ change_option_setting (SCM args, scm_t_option options[], unsigned int n, const c
 	flags[i] = options[i].val;
     }
 
-  while (!SCM_NULLP (args))
+  while (!SCM_NULL_OR_NIL_P (args))
     {
       SCM name = SCM_CAR (args);
       int found = 0;
@@ -257,7 +258,7 @@ scm_options (SCM args, scm_t_option options[], unsigned int n, const char *s)
 {
   if (SCM_UNBNDP (args))
     return get_option_setting (options, n);
-  else if (!SCM_NULLP (args) && !SCM_CONSP (args))
+  else if (!SCM_NULL_OR_NIL_P (args) && !SCM_CONSP (args))
     /* Dirk:FIXME:: This criterion should be improved.  IMO it is better to
      * demand that args is #t if documentation should be shown than to say
      * that every argument except a list will print out documentation.  */
diff --git a/libguile/posix.c b/libguile/posix.c
index 6e2393570..1ef46d1db 100644
--- a/libguile/posix.c
+++ b/libguile/posix.c
@@ -54,6 +54,7 @@
 #include "libguile/feature.h"
 #include "libguile/strings.h"
 #include "libguile/vectors.h"
+#include "libguile/lang.h"
 
 #include "libguile/validate.h"
 #include "libguile/posix.h"
@@ -916,7 +917,7 @@ environ_list_to_c (SCM envlist, int arg, const char *proc)
   result = (char **) malloc ((num_strings + 1) * sizeof (char *));
   if (result == NULL)
     scm_memory_error (proc);
-  for (i = 0; !SCM_NULLP (envlist); ++i, envlist = SCM_CDR (envlist))
+  for (i = 0; !SCM_NULL_OR_NIL_P (envlist); ++i, envlist = SCM_CDR (envlist))
     {
       SCM str = SCM_CAR (envlist);
       int len;
diff --git a/libguile/print.c b/libguile/print.c
index 64bd23e89..e28284637 100644
--- a/libguile/print.c
+++ b/libguile/print.c
@@ -62,6 +62,7 @@
 #include "libguile/strings.h"
 #include "libguile/strports.h"
 #include "libguile/vectors.h"
+#include "libguile/lang.h"
 
 #include "libguile/validate.h"
 #include "libguile/print.h"
@@ -74,7 +75,7 @@
 
 char *scm_isymnames[] =
 {
-  /* This table must agree with the declarations */
+  /* This table must agree with the list of SCM_IM_ constants in tags.h */
   "#@and",
   "#@begin",
   "#@case",
@@ -113,17 +114,17 @@ char *scm_isymnames[] =
   /* Multi-language support */
   
   "#@nil-cond",
-  "#@nil-ify",
-  "#@t-ify",
-  "#@0-cond",
-  "#@0-ify",
-  "#@1-ify",
   "#@bind",
   
   "#@delay",
   "#@call-with-values",
 
-  "#<unbound>"
+  "#<unbound>",
+
+  /* Elisp nil value.  This is its Scheme name; whenever it's printed
+     in Elisp, it should appear as the symbol `nil'. */
+
+  "#nil"
 };
 
 scm_t_option scm_print_opts[] = {
@@ -781,7 +782,7 @@ scm_iprlist (char *hdr,SCM exp,int tlr,SCM port,scm_print_state *pstate)
       /* CHECK_INTS; */
       scm_iprin1 (SCM_CAR (exp), port, pstate);
     }
-  if (!SCM_NULLP (exp))
+  if (!SCM_NULL_OR_NIL_P (exp))
     {
       scm_puts (" . ", port);
       scm_iprin1 (exp, port, pstate);
@@ -822,7 +823,7 @@ fancy_printing:
 	scm_iprin1 (SCM_CAR (exp), port, pstate);
       }
   }
-  if (!SCM_NULLP (exp))
+  if (!SCM_NULL_OR_NIL_P (exp))
     {
       scm_puts (" . ", port);
       scm_iprin1 (exp, port, pstate);
diff --git a/libguile/read.c b/libguile/read.c
index 1b8979ce1..33a7e37f0 100644
--- a/libguile/read.c
+++ b/libguile/read.c
@@ -72,7 +72,7 @@ scm_t_option scm_read_opts[] = {
   { SCM_OPTION_BOOLEAN, "case-insensitive", 0,
     "Convert symbols to lower case."},
   { SCM_OPTION_SCM, "keywords", SCM_UNPACK (SCM_BOOL_F),
-    "Style of keyword recognition: #f or 'prefix"}
+    "Style of keyword recognition: #f or 'prefix."}
 };
 
 SCM_DEFINE (scm_read_options, "read-options-interface", 0, 1, 0, 
diff --git a/libguile/script.c b/libguile/script.c
index 72fc04180..b782dbce7 100644
--- a/libguile/script.c
+++ b/libguile/script.c
@@ -515,7 +515,7 @@ scm_compile_shell_switches (int argc, char **argv)
       else if (! strcmp (argv[i], "-e")) /* entry point */
 	{
 	  if (++i < argc)
-	    entry_point = gh_symbol2scm (argv[i]);
+	    entry_point = scm_str2symbol (argv[i]);
 	  else
 	    scm_shell_usage (1, "missing argument to `-e' switch");
 	}
diff --git a/libguile/sort.c b/libguile/sort.c
index 05991b7b3..7a3b61ab8 100644
--- a/libguile/sort.c
+++ b/libguile/sort.c
@@ -86,6 +86,7 @@ char *alloca ();
 #include "libguile/feature.h"
 #include "libguile/root.h"
 #include "libguile/vectors.h"
+#include "libguile/lang.h"
 
 #include "libguile/validate.h"
 #include "libguile/sort.h"
@@ -457,7 +458,7 @@ SCM_DEFINE (scm_sorted_p, "sorted?", 2, 0, 0,
   SCM *vp;
   cmp_fun_t cmp = scm_cmp_function (less);
 
-  if (SCM_NULLP (items))
+  if (SCM_NULL_OR_NIL_P (items))
     return SCM_BOOL_T;
 
   SCM_VALIDATE_NIM (2,less);
@@ -530,9 +531,9 @@ SCM_DEFINE (scm_merge, "merge", 3, 0, 0,
   cmp_fun_t cmp = scm_cmp_function (less);
   SCM_VALIDATE_NIM (3,less);
 
-  if (SCM_NULLP (alist))
+  if (SCM_NULL_OR_NIL_P (alist))
     return blist;
-  else if (SCM_NULLP (blist))
+  else if (SCM_NULL_OR_NIL_P (blist))
     return alist;
   else
     {
@@ -584,9 +585,9 @@ scm_merge_list_x (SCM alist, SCM blist,
 {
   SCM build, last;
 
-  if (SCM_NULLP (alist))
+  if (SCM_NULL_OR_NIL_P (alist))
     return blist;
-  else if (SCM_NULLP (blist))
+  else if (SCM_NULL_OR_NIL_P (blist))
     return alist;
   else
     {
@@ -641,9 +642,9 @@ SCM_DEFINE (scm_merge_x, "merge!", 3, 0, 0,
   long alen, blen;		/* list lengths */
 
   SCM_VALIDATE_NIM (3,less);
-  if (SCM_NULLP (alist))
+  if (SCM_NULL_OR_NIL_P (alist))
     return blist;
-  else if (SCM_NULLP (blist))
+  else if (SCM_NULL_OR_NIL_P (blist))
     return alist;
   else
     {
@@ -715,8 +716,8 @@ SCM_DEFINE (scm_sort_x, "sort!", 2, 0, 0,
 #define FUNC_NAME s_scm_sort_x
 {
   long len;			/* list/vector length */
-  if (SCM_NULLP(items))
-    return SCM_EOL;
+  if (SCM_NULL_OR_NIL_P (items))
+    return items;
 
   SCM_VALIDATE_NIM (2,less);
 
@@ -748,8 +749,8 @@ SCM_DEFINE (scm_sort, "sort", 2, 0, 0,
 	    "elements.  This is not a stable sort.")
 #define FUNC_NAME s_scm_sort
 {
-  if (SCM_NULLP(items))
-    return SCM_EOL;
+  if (SCM_NULL_OR_NIL_P (items))
+    return items;
 
   SCM_VALIDATE_NIM (2,less);
   if (SCM_CONSP (items))
@@ -846,8 +847,8 @@ SCM_DEFINE (scm_stable_sort_x, "stable-sort!", 2, 0, 0,
 {
   long len;			/* list/vector length */
 
-  if (SCM_NULLP (items))
-    return SCM_EOL;
+  if (SCM_NULL_OR_NIL_P (items))
+    return items;
 
   SCM_VALIDATE_NIM (2,less);
   if (SCM_CONSP (items))
@@ -885,8 +886,8 @@ SCM_DEFINE (scm_stable_sort, "stable-sort", 2, 0, 0,
 #define FUNC_NAME s_scm_stable_sort
 {
   long len;			/* list/vector length */
-  if (SCM_NULLP (items))
-    return SCM_EOL;
+  if (SCM_NULL_OR_NIL_P (items))
+    return items;
 
   SCM_VALIDATE_NIM (2,less);
   if (SCM_CONSP (items))
diff --git a/libguile/srcprop.c b/libguile/srcprop.c
index 48df4e6a6..f00828b79 100644
--- a/libguile/srcprop.c
+++ b/libguile/srcprop.c
@@ -161,7 +161,7 @@ scm_srcprops_to_plist (SCM obj)
     plist = scm_acons (scm_sym_filename, SRCPROPFNAME (obj), plist);
   plist = scm_acons (scm_sym_column, SCM_MAKINUM (SRCPROPCOL (obj)), plist);
   plist = scm_acons (scm_sym_line, SCM_MAKINUM (SRCPROPLINE (obj)), plist);
-  plist = scm_acons (scm_sym_breakpoint, SRCPROPBRK (obj), plist);
+  plist = scm_acons (scm_sym_breakpoint, SCM_BOOL (SRCPROPBRK (obj)), plist);
   return plist;
 }
 
@@ -224,7 +224,7 @@ SCM_DEFINE (scm_source_property, "source-property", 2, 0, 0,
   p = scm_hashq_ref (scm_source_whash, obj, SCM_EOL);
   if (!SRCPROPSP (p))
     goto plist;
-  if      (SCM_EQ_P (scm_sym_breakpoint, key)) p = SRCPROPBRK (p);
+  if      (SCM_EQ_P (scm_sym_breakpoint, key)) p = SCM_BOOL (SRCPROPBRK (p));
   else if (SCM_EQ_P (scm_sym_line,       key)) p = SCM_MAKINUM (SRCPROPLINE (p));
   else if (SCM_EQ_P (scm_sym_column,     key)) p = SCM_MAKINUM (SRCPROPCOL (p));
   else if (SCM_EQ_P (scm_sym_filename,   key)) p = SRCPROPFNAME (p);
diff --git a/libguile/srcprop.h b/libguile/srcprop.h
index 795aaf435..89f72e5ab 100644
--- a/libguile/srcprop.h
+++ b/libguile/srcprop.h
@@ -97,8 +97,7 @@ typedef struct scm_t_srcprops_chunk
 #define SCM_SOURCE_PROPERTY_FLAG_BREAK (1L << 16)
 
 #define SRCPROPSP(p) (SCM_TYP16_PREDICATE (scm_tc16_srcprops, p))
-#define SRCPROPBRK(p) \
-  (SCM_BOOL (SCM_CELL_WORD_0 (p) & SCM_SOURCE_PROPERTY_FLAG_BREAK))
+#define SRCPROPBRK(p) (SCM_CELL_WORD_0 (p) & SCM_SOURCE_PROPERTY_FLAG_BREAK)
 #define SRCPROPPOS(p) ((scm_t_srcprops *) SCM_CELL_WORD_1 (p))->pos
 #define SRCPROPLINE(p) (SRCPROPPOS(p) >> 12)
 #define SRCPROPCOL(p) (SRCPROPPOS(p) & 0x0fffL)
@@ -118,7 +117,7 @@ typedef struct scm_t_srcprops_chunk
 
 #define SRCBRKP(x) (!SCM_IMP (t.arg1 = scm_whash_lookup (scm_source_whash, (x)))\
 		    && SRCPROPSP (t.arg1)\
-		    && (SCM_CELL_WORD_0 (t.arg1) & (1L << 16)))
+		    && SRCPROPBRK (t.arg1))
 
 #define PROCTRACEP(x) (!SCM_FALSEP (scm_procedure_property (x, scm_sym_trace)))
 
diff --git a/libguile/tags.h b/libguile/tags.h
index 3f937afa1..1e9090ede 100644
--- a/libguile/tags.h
+++ b/libguile/tags.h
@@ -458,15 +458,10 @@ SCM_API char *scm_isymnames[];   /* defined in print.c */
 /* Multi-language support */
 
 #define SCM_IM_NIL_COND		SCM_MAKISYM (25)
-#define SCM_IM_NIL_IFY		SCM_MAKISYM (26)
-#define SCM_IM_T_IFY		SCM_MAKISYM (27)
-#define SCM_IM_0_COND		SCM_MAKISYM (28)
-#define SCM_IM_0_IFY		SCM_MAKISYM (29)
-#define SCM_IM_1_IFY		SCM_MAKISYM (30)
-#define SCM_IM_BIND		SCM_MAKISYM (31)
+#define SCM_IM_BIND		SCM_MAKISYM (26)
 
-#define SCM_IM_DELAY		SCM_MAKISYM (32)
-#define SCM_IM_CALL_WITH_VALUES SCM_MAKISYM (33)
+#define SCM_IM_DELAY		SCM_MAKISYM (27)
+#define SCM_IM_CALL_WITH_VALUES SCM_MAKISYM (28)
 
 /* When a variable is unbound this is marked by the SCM_UNDEFINED
  * value.  The following is an unbound value which can be handled on
@@ -477,10 +472,13 @@ SCM_API char *scm_isymnames[];   /* defined in print.c */
  * 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 (34)
+#define SCM_UNBOUND		SCM_MAKIFLAG (29)
 
 #define SCM_UNBNDP(x)		(SCM_EQ_P ((x), SCM_UNDEFINED))
 
+/* The Elisp nil value. */
+#define SCM_ELISP_NIL		SCM_MAKIFLAG (30)
+
 
 
 /* Dispatching aids:
diff --git a/libguile/throw.c b/libguile/throw.c
index 04c5263e1..91f07f61a 100644
--- a/libguile/throw.c
+++ b/libguile/throw.c
@@ -58,6 +58,7 @@
 #include "libguile/stacks.h"
 #include "libguile/fluids.h"
 #include "libguile/ports.h"
+#include "libguile/lang.h"
 
 #include "libguile/validate.h"
 #include "libguile/throw.h"
@@ -401,7 +402,7 @@ scm_handle_by_proc_catching_all (void *handler_data, SCM tag, SCM throw_args)
 int
 scm_exit_status (SCM args)
 {
-  if (SCM_NNULLP (args))
+  if (!SCM_NULL_OR_NIL_P (args))
     {
       SCM cqa = SCM_CAR (args);
       
diff --git a/libguile/validate.h b/libguile/validate.h
index 21aadbe57..9068b8278 100644
--- a/libguile/validate.h
+++ b/libguile/validate.h
@@ -323,6 +323,8 @@
 
 #define SCM_VALIDATE_NULL(pos, scm) SCM_MAKE_VALIDATE (pos, scm, NULLP)
 
+#define SCM_VALIDATE_NULL_OR_NIL(pos, scm) SCM_MAKE_VALIDATE (pos, scm, NULL_OR_NIL_P)
+
 #define SCM_VALIDATE_CONS(pos, scm) SCM_MAKE_VALIDATE (pos, scm, CONSP)
 
 #define SCM_VALIDATE_LIST(pos, lst) \
diff --git a/libguile/vectors.c b/libguile/vectors.c
index db9c18669..5868ba4f0 100644
--- a/libguile/vectors.c
+++ b/libguile/vectors.c
@@ -46,6 +46,7 @@
 #include "libguile/eq.h"
 #include "libguile/root.h"
 #include "libguile/strings.h"
+#include "libguile/lang.h"
 
 #include "libguile/validate.h"
 #include "libguile/vectors.h"
@@ -101,7 +102,7 @@ SCM_DEFINE (scm_vector, "vector", 0, 0, 1,
   SCM_VALIDATE_LIST_COPYLEN (1, l, i);
   res = scm_c_make_vector (i, SCM_UNSPECIFIED);
   data = SCM_VELTS (res);
-  while (!SCM_NULLP (l)) 
+  while (!SCM_NULL_OR_NIL_P (l)) 
     {
       *data++ = SCM_CAR (l);
       l = SCM_CDR (l);
diff --git a/libguile/weaks.c b/libguile/weaks.c
index 277b102b3..d5fc5a060 100644
--- a/libguile/weaks.c
+++ b/libguile/weaks.c
@@ -44,6 +44,7 @@
 
 #include "libguile/_scm.h"
 #include "libguile/vectors.h"
+#include "libguile/lang.h"
 
 #include "libguile/validate.h"
 #include "libguile/weaks.h"
@@ -144,7 +145,7 @@ SCM_DEFINE (scm_weak_vector, "weak-vector", 0, 0, 1,
   res = scm_make_weak_vector (SCM_MAKINUM (i), SCM_UNSPECIFIED);
   data = SCM_VELTS (res);
 
-  while (!SCM_NULLP (l))
+  while (!SCM_NULL_OR_NIL_P (l))
     {
       *data++ = SCM_CAR (l);
       l = SCM_CDR (l);