Rename badly named default_bool_arg

* lib.h (default_bool_arg): Inline function renamed to
default_null_arg.

* eval.c (if_fun, pad, ginterate, giterate, range_star, range,
constantp, macroexpand_1, macro_form_p, expand_with_free_refs,
do_expand, eval_intrinsic, func_get_name, make_env_intrinsic):
Follow rename.

* arith.c (lognot): Likewise.

* gc.c (gc_finalize): Likewise.

* glob.c (glob_wrap): Likewise.

* hash.c (group_reduce, gethash_n): Likewise.

* lib.c (print, multi_sort, lazy_str, vector, iff, tok_str,
split_str_keep, search_str, remove_if, val): Likewise.

* match.c (match_fun): Likewise.

* parser.c (lisp_parse_impl, regex_parse): Likewise.

* rand.c (make_random_state): Likewise.

* regex.c (read_until_match, search_regex, regex_compile):
Likewise.

* socket.c (sock_accept, sock_connect): Likewise.

* stream.c (open_files_star, open_files, run, open_process,
open_tail, get_string, record_adapter): Likewise.

* struct.c (static_slot_ensure, static_slot_ens_rec,
clear_struct, make_struct_type): Likewise.

* sysif.c (exec_wrap, errno_wrap, cobj_ops_init): Likewise.

* unwind.c (uw_capture_cont, uw_find_frames_impl): Likewise.

16 files changed, 65 insertions, 65 deletions

diff --git a/arith.c b/arith.c
index 6d6dd9f9..241dd56f 100644
--- a/arith.c
+++ b/arith.c
@@ -2306,7 +2306,7 @@ val lognot(val a, val bits)
 {
   val b;
 
-  if (default_bool_arg(bits))
+  if (default_null_arg(bits))
     return comp_trunc(a, bits);
 
   switch (type(a)) {
diff --git a/eval.c b/eval.c
index 6f5d89c3..420e58a1 100644
--- a/eval.c
+++ b/eval.c
@@ -142,9 +142,9 @@ val copy_env(val oenv)
  */
 static val make_env_intrinsic(val vbindings, val fbindings, val up_env)
 {
-  vbindings = default_bool_arg(vbindings);
-  fbindings = default_bool_arg(fbindings);
-  up_env = default_bool_arg(up_env);
+  vbindings = default_null_arg(vbindings);
+  fbindings = default_null_arg(fbindings);
+  up_env = default_null_arg(up_env);
   return make_env(vbindings, fbindings, up_env);
 }
 
@@ -508,7 +508,7 @@ val lookup_fun(val env, val sym)
 
 val func_get_name(val fun, val env)
 {
-  env = default_bool_arg(env);
+  env = default_null_arg(env);
 
   if (env) {
     type_check(env, ENV);
@@ -1332,7 +1332,7 @@ val eval_intrinsic(val form, val env)
                  expand(form, nil));
   val loading = cdr(lookup_var(dyn_env, load_recursive_s));
   val ret = ((void) (loading || uw_release_deferred_warnings()),
-             eval(form_ex, default_bool_arg(env), form));
+             eval(form_ex, default_null_arg(env), form));
   last_form_expanded = lfx_save;
   last_form_evaled = lfe_save;
   return ret;
@@ -3962,7 +3962,7 @@ static val do_expand(val form, val menv)
 {
   val macro = nil;
 
-  menv = default_bool_arg(menv);
+  menv = default_null_arg(menv);
 
   if (nilp(form)) {
     return nil;
@@ -4373,8 +4373,8 @@ static val gather_free_refs_nw(val info_cons, val exc,
 static val expand_with_free_refs(val form, val menv_in, val upto_menv_in)
 {
   val ret;
-  val menv = default_bool_arg(menv_in);
-  val upto_menv = default_bool_arg(upto_menv_in);
+  val menv = default_null_arg(menv_in);
+  val upto_menv = default_null_arg(upto_menv_in);
   uw_frame_t uw_handler;
   val info_cons_free = cons(nil, nil);
   val info_cons_bound = cons(nil, nil);
@@ -4393,7 +4393,7 @@ static val expand_with_free_refs(val form, val menv_in, val upto_menv_in)
 
 val macro_form_p(val form, val menv)
 {
-  menv = default_bool_arg(menv);
+  menv = default_null_arg(menv);
 
   if (bindable(form) && lookup_symac(menv, form))
     return t;
@@ -4406,7 +4406,7 @@ static val macroexpand_1(val form, val menv)
 {
   val macro;
 
-  menv = default_bool_arg(menv);
+  menv = default_null_arg(menv);
 
   if (consp(form) && (macro = lookup_mac(menv, car(form)))) {
     val mac_expand = expand_macro(form, macro, menv);
@@ -4448,7 +4448,7 @@ static val constantp_noex(val form)
 
 static val constantp(val form, val env_in)
 {
-  val env = default_bool_arg(env_in);
+  val env = default_null_arg(env_in);
 
   if (consp(form)) {
     if (car(form) == quote_s) {
@@ -4762,7 +4762,7 @@ static val range_func(val env, val lcons)
 static val range(val from_in, val to_in, val step_in)
 {
   val from = default_arg(from_in, zero);
-  val to = default_bool_arg(to_in);
+  val to = default_null_arg(to_in);
   val step = default_arg(step_in, if3(to && gt(from, to), negone, one));
   val env = cons(from, cons(to, step));
 
@@ -4796,7 +4796,7 @@ static val range_star_func(val env, val lcons)
 static val range_star(val from_in, val to_in, val step_in)
 {
   val from = default_arg(from_in, zero);
-  val to = default_bool_arg(to_in);
+  val to = default_null_arg(to_in);
 
   if (eql(from, to)) {
     return nil;
@@ -4850,7 +4850,7 @@ static val giterate_func(val env, val lcons)
 
 static val giterate(val while_pred, val gen_fun, val init_val)
 {
-  init_val = default_bool_arg(init_val);
+  init_val = default_null_arg(init_val);
 
   if (!funcall1(while_pred, init_val)) {
     return nil;
@@ -4878,7 +4878,7 @@ static val ginterate_func(val env, val lcons)
 
 static val ginterate(val while_pred, val gen_fun, val init_val)
 {
-  init_val = default_bool_arg(init_val);
+  init_val = default_null_arg(init_val);
 
   if (!funcall1(while_pred, init_val)) {
     return cons(init_val, nil);
@@ -5021,7 +5021,7 @@ static val pad_func(val env, val lcons)
 
 static val pad(val list, val item_in, val count)
 {
-  val item = default_bool_arg(item_in);
+  val item = default_null_arg(item_in);
 
   switch (type(list)) {
   case NIL:
@@ -5158,7 +5158,7 @@ static void reg_symacro(val sym, val form)
 
 static val if_fun(val cond, val then, val alt)
 {
-  return if3(cond, then, default_bool_arg(alt));
+  return if3(cond, then, default_null_arg(alt));
 }
 
 static val or_fun(struct args *vals)
diff --git a/gc.c b/gc.c
index 06e00be9..4e7c9eb9 100644
--- a/gc.c
+++ b/gc.c
@@ -846,7 +846,7 @@ val gc_finalize(val obj, val fun, val rev_order_p)
 {
   type_check(fun, FUN);
 
-  rev_order_p = default_bool_arg(rev_order_p);
+  rev_order_p = default_null_arg(rev_order_p);
 
   if (is_ptr(obj)) {
     struct fin_reg *f = coerce(struct fin_reg *, chk_malloc(sizeof *f));
diff --git a/glob.c b/glob.c
index fc71e091..ae66ab90 100644
--- a/glob.c
+++ b/glob.c
@@ -77,7 +77,7 @@ val glob_wrap(val pattern, val flags, val errfunc)
                            "its error callback function"), nao);
   }
 
-  s_errfunc = default_bool_arg(errfunc);
+  s_errfunc = default_null_arg(errfunc);
 
   (void) glob(pat_u8, c_flags, s_errfunc ? errfunc_thunk : 0, &gl);
 
diff --git a/hash.c b/hash.c
index c9aa5b6a..d1a60da5 100644
--- a/hash.c
+++ b/hash.c
@@ -716,7 +716,7 @@ val gethash_f(val hash, val key, loc found)
 val gethash_n(val hash, val key, val notfound_val)
 {
   val existing = gethash_e(hash, key);
-  return if3(existing, cdr(existing), default_bool_arg(notfound_val));
+  return if3(existing, cdr(existing), default_null_arg(notfound_val));
 }
 
 val sethash(val hash, val key, val value)
@@ -1085,7 +1085,7 @@ val group_by(val func, val seq, struct args *hashv_args)
 val group_reduce(val hash, val by_fun, val reduce_fun, val seq,
                  val initval, val filter_fun)
 {
-  initval = default_bool_arg(initval);
+  initval = default_null_arg(initval);
 
   if (vectorp(seq)) {
     cnum i, len;
diff --git a/lib.c b/lib.c
index cb2594f5..358bda30 100644
--- a/lib.c
+++ b/lib.c
@@ -143,7 +143,7 @@ val chr(wchar_t ch);
 val eq(val a, val b);
 val null(val v);
 int null_or_missing_p(val v);
-val default_bool_arg(val arg);
+val default_null_arg(val arg);
 #endif
 
 val identity(val obj)
@@ -1523,7 +1523,7 @@ val rmember_if(val pred, val list, val key)
 static val rem_impl(val (*eqfun)(val, val), val name,
                     val obj, val seq_in, val keyfun_in)
 {
-  val keyfun = default_bool_arg(keyfun_in);
+  val keyfun = default_null_arg(keyfun_in);
 
   switch (type(seq_in)) {
   case NIL:
@@ -1591,7 +1591,7 @@ static val rem_impl(val (*eqfun)(val, val), val name,
 
 val remove_if(val pred, val seq_in, val keyfun_in)
 {
-  val keyfun = default_bool_arg(keyfun_in);
+  val keyfun = default_null_arg(keyfun_in);
 
   switch (type(seq_in)) {
   case NIL:
@@ -3436,7 +3436,7 @@ const wchar_t *c_str(val obj)
 
 val search_str(val haystack, val needle, val start_num, val from_end)
 {
-  from_end = default_bool_arg(from_end);
+  from_end = default_null_arg(from_end);
   start_num = default_arg(start_num, zero);
 
   if (length_str_lt(haystack, start_num)) {
@@ -3926,7 +3926,7 @@ val scat(val sep, ...)
 
 val split_str_keep(val str, val sep, val keep_sep)
 {
-  keep_sep = default_bool_arg(keep_sep);
+  keep_sep = default_null_arg(keep_sep);
 
   if (regexp(sep)) {
     list_collect_decl (out, iter);
@@ -4047,7 +4047,7 @@ val tok_str(val str, val tok_regex, val keep_sep)
   val slen = length(str);
   int prev_empty = 1;
 
-  keep_sep = default_bool_arg(keep_sep);
+  keep_sep = default_null_arg(keep_sep);
 
   if (opt_compat && opt_compat <= 155) for (;;) {
     cons_bind (new_pos, len, search_regex(str, tok_regex, pos, nil));
@@ -6558,7 +6558,7 @@ static val do_iff(val env, struct args *args_in)
 val iff(val condfun, val thenfun, val elsefun)
 {
   thenfun = default_arg(thenfun, identity_f);
-  elsefun = default_bool_arg(elsefun);
+  elsefun = default_null_arg(elsefun);
   return func_f0v(cons(condfun, cons(thenfun, elsefun)), do_iff);
 }
 
@@ -6591,7 +6591,7 @@ val vector(val length, val initval)
                                      length, nao));
   val vec = make_obj();
   vec->v.type = VEC;
-  initval = default_bool_arg(initval);
+  initval = default_null_arg(initval);
 #if HAVE_VALGRIND
   vec->v.vec_true_start = v;
 #endif
@@ -7028,7 +7028,7 @@ val lazy_str(val lst, val term, val limit)
                          chk_calloc(1, sizeof *obj->ls.props));
 
   term = default_arg(term, lit("\n"));
-  limit = default_bool_arg(limit);
+  limit = default_null_arg(limit);
 
   if (nilp(lst)) {
     obj->ls.prefix = null_string;
@@ -7960,7 +7960,7 @@ val multi_sort(val lists, val funcs, val key_funcs)
 {
   val tuples = mapcarl(list_f, nullify(lists));
 
-  key_funcs = default_bool_arg(key_funcs);
+  key_funcs = default_null_arg(key_funcs);
 
   if (functionp(funcs))
     funcs = cons(funcs, nil);
@@ -10356,7 +10356,7 @@ val obj_print(val obj, val out, val pretty)
 val print(val obj, val stream, val pretty)
 {
   return obj_print(obj, default_arg(stream, std_output),
-                   default_bool_arg(pretty));
+                   default_null_arg(pretty));
 }
 
 val pprint(val obj, val stream)
diff --git a/lib.h b/lib.h
index df401e58..1f9537cf 100644
--- a/lib.h
+++ b/lib.h
@@ -1078,7 +1078,7 @@ INLINE int null_or_missing_p(val v) { return (nilp(v) || missingp(v)); }
 
 #define default_arg(arg, dfl) if3(null_or_missing_p(arg), dfl, arg)
 
-INLINE val default_bool_arg(val arg)
+INLINE val default_null_arg(val arg)
 {
   return if3(missingp(arg), nil, arg);
 }
diff --git a/match.c b/match.c
index 6fda6f19..b7692e11 100644
--- a/match.c
+++ b/match.c
@@ -4561,12 +4561,12 @@ val match_fun(val name, val args, val input_in, val files_in)
 {
   val call = cons(name, args);
   val spec = cons(cons(call, nil), nil);
-  val input = default_bool_arg(input_in);
+  val input = default_null_arg(input_in);
   val in_stream_p = streamp(input);
   val curfile = if3(in_stream_p,
                     stream_get_prop(input, name_k),
                     lit("list"));
-  val files = cons(curfile, default_bool_arg(files_in));
+  val files = cons(curfile, default_null_arg(files_in));
   val in_bindings = cdr(uw_get_match_context());
   val data = if3(streamp(input),
                  lazy_stream_cons(input),
diff --git a/parser.c b/parser.c
index a419ace6..11249945 100644
--- a/parser.c
+++ b/parser.c
@@ -476,7 +476,7 @@ val regex_parse(val string, val error_stream)
   val stream = make_string_byte_input_stream(string);
   parser_t parser;
 
-  error_stream = default_bool_arg(error_stream);
+  error_stream = default_null_arg(error_stream);
   std_error = if3(error_stream == t, std_output, or2(error_stream, std_null));
 
   parser_common_init(&parser);
@@ -501,11 +501,11 @@ static val lisp_parse_impl(val interactive, val source_in, val error_stream,
                            val error_return_val, val name_in, val lineno)
 {
   uses_or2;
-  val source = default_bool_arg(source_in);
+  val source = default_null_arg(source_in);
   val input_stream = if3(stringp(source),
                          make_string_byte_input_stream(source),
                          or2(source, std_input));
-  val name = or2(default_bool_arg(name_in),
+  val name = or2(default_null_arg(name_in),
                  if3(stringp(source),
                      lit("string"),
                      stream_get_prop(input_stream, name_k)));
@@ -518,7 +518,7 @@ static val lisp_parse_impl(val interactive, val source_in, val error_stream,
 
   dyn_env = make_env(nil, nil, dyn_env);
 
-  error_stream = default_bool_arg(error_stream);
+  error_stream = default_null_arg(error_stream);
   error_stream = if3(error_stream == t, std_output, or2(error_stream, std_null));
   class_check (error_stream, stream_s);
 
diff --git a/rand.c b/rand.c
index ed429a4b..d29fbecc 100644
--- a/rand.c
+++ b/rand.c
@@ -117,8 +117,8 @@ val make_random_state(val seed, val warmup)
   struct rand_state *r = coerce(struct rand_state *,
                                 cobj_handle(rs, random_state_s));
 
-  seed = default_bool_arg(seed);
-  warmup = default_bool_arg(warmup);
+  seed = default_null_arg(seed);
+  warmup = default_null_arg(warmup);
 
   if (bignump(seed)) {
     int dig, bit;
diff --git a/regex.c b/regex.c
index 3bbd3492..9568d312 100644
--- a/regex.c
+++ b/regex.c
@@ -2104,7 +2104,7 @@ val regex_compile(val regex_sexp, val error_stream)
   val regex_source;
 
   if (stringp(regex_sexp)) {
-    regex_sexp = regex_parse(regex_sexp, default_bool_arg(error_stream));
+    regex_sexp = regex_parse(regex_sexp, default_null_arg(error_stream));
     return if2(regex_sexp, regex_compile(regex_sexp, error_stream));
   }
 
@@ -2458,7 +2458,7 @@ val search_regex(val haystack, val needle_regex, val start,
 {
   val slen = nil;
   start = default_arg(start, zero);
-  from_end = default_bool_arg(from_end);
+  from_end = default_null_arg(from_end);
 
   if (minusp(start)) {
     slen = length_str(haystack);
@@ -2965,7 +2965,7 @@ val read_until_match(val regex, val stream_in, val include_match_in)
   val stack = nil;
   val match = nil;
   val stream = default_arg(stream_in, std_input);
-  val include_match = default_bool_arg(include_match_in);
+  val include_match = default_null_arg(include_match_in);
 
   regex_machine_init(&regm, regex);
 
diff --git a/socket.c b/socket.c
index 0ef35048..5ecaa78c 100644
--- a/socket.c
+++ b/socket.c
@@ -787,7 +787,7 @@ static val sock_connect(val sock, val sockaddr, val timeout)
     sockaddr_pack(sockaddr, family, &sa, &salen);
 
     if (to_connect(c_num(sfd), coerce(struct sockaddr *, &sa), salen,
-                   sock, sockaddr, default_bool_arg(timeout)) != 0)
+                   sock, sockaddr, default_null_arg(timeout)) != 0)
       uw_throwf(socket_error_s, lit("sock-connect ~s to addr ~s: ~d/~s"),
                 sock, sockaddr, num(errno), string_utf8(strerror(errno)), nao);
 
@@ -861,7 +861,7 @@ static val sock_accept(val sock, val mode_str, val timeout_in)
   struct sockaddr_storage sa;
   socklen_t salen = sizeof sa;
   val peer = nil;
-  val timeout = default_bool_arg(timeout_in);
+  val timeout = default_null_arg(timeout_in);
 
   if (!sfd)
     goto badfd;
diff --git a/stream.c b/stream.c
index 6df413f9..b00b4720 100644
--- a/stream.c
+++ b/stream.c
@@ -2584,7 +2584,7 @@ val record_adapter(val regex, val stream, val include_match)
                                           rec_adapter->co.handle);
 
   rb->regex = regex;
-  rb->include_match = default_bool_arg(include_match);
+  rb->include_match = default_null_arg(include_match);
   return rec_adapter;
 }
 
@@ -3557,7 +3557,7 @@ val get_string(val stream_in, val nchars, val close_after_p)
 {
   val stream = default_arg(stream_in, std_input);
   val strstream = make_string_output_stream();
-  nchars = default_bool_arg(nchars);
+  nchars = default_null_arg(nchars);
   val ch;
 
   if (nchars) {
@@ -3633,7 +3633,7 @@ val open_tail(val path, val mode_str, val seek_end_p)
   val stream;
   unsigned long state = 0;
 
-  if (f && default_bool_arg(seek_end_p))
+  if (f && default_null_arg(seek_end_p))
     if (fseek(f, 0, SEEK_END) < 0)
       uw_throwf(file_error_s, lit("error seeking to end of ~a: ~d/~s"),
                 path, num(errno), string_utf8(strerror(errno)), nao);
@@ -3755,7 +3755,7 @@ val open_process(val name, val mode_str, val args)
   struct save_fds sfds;
   val ret = nil;
 
-  args = default_bool_arg(args);
+  args = default_null_arg(args);
   nargs = c_num(length(args)) + 1;
 
   fds_init(&sfds);
@@ -3937,7 +3937,7 @@ static val win_make_cmdline(val args)
 
 val open_process(val name, val mode_str, val args)
 {
-  val win_cmdline = win_make_cmdline(cons(name, default_bool_arg(args)));
+  val win_cmdline = win_make_cmdline(cons(name, default_null_arg(args)));
   return open_command(win_cmdline, mode_str);
 }
 #endif
@@ -3952,7 +3952,7 @@ static val run(val name, val args)
   struct save_fds sfds;
   val ret = nil;
 
-  args = default_bool_arg(args);
+  args = default_null_arg(args);
   nargs = c_num(length(args)) + 1;
 
   argv = coerce(char **, chk_malloc((nargs + 1) * sizeof *argv));
@@ -4023,7 +4023,7 @@ static val run(val command, val args)
   int i, nargs, status;
   struct save_fds sfds;
 
-  args = default_bool_arg(args);
+  args = default_null_arg(args);
   nargs = c_num(length(args)) + 1;
 
   fds_init(&sfds);
@@ -4083,7 +4083,7 @@ val rename_path(val from, val to)
 
 static val open_files(val file_list, val substitute_stream)
 {
-  substitute_stream = default_bool_arg(substitute_stream);
+  substitute_stream = default_null_arg(substitute_stream);
 
   if (nilp(file_list) && substitute_stream) {
     return substitute_stream;
@@ -4094,7 +4094,7 @@ static val open_files(val file_list, val substitute_stream)
 
 static val open_files_star(val file_list, val substitute_stream)
 {
-  substitute_stream = default_bool_arg(substitute_stream);
+  substitute_stream = default_null_arg(substitute_stream);
 
   if (nilp(file_list) && substitute_stream) {
     return substitute_stream;
diff --git a/struct.c b/struct.c
index bd9644be..84977da6 100644
--- a/struct.c
+++ b/struct.c
@@ -289,7 +289,7 @@ val make_struct_type(val name, val super,
     st->stinitfun = static_initfun;
     st->initfun = initfun;
     st->boactor = boactor;
-    st->postinitfun = default_bool_arg(postinitfun);
+    st->postinitfun = default_null_arg(postinitfun);
     st->dvtypes = nil;
 
     gc_finalize(stype, struct_type_finalize_f, nil);
@@ -637,7 +637,7 @@ val clear_struct(val strct, val value)
   const val self = lit("clear-struct");
   struct struct_inst *si = struct_handle(strct, self);
   struct struct_type *st = si->type;
-  val clear_val = default_bool_arg(value);
+  val clear_val = default_null_arg(value);
   cnum i;
 
   check_init_lazy_struct(strct, si);
@@ -1046,7 +1046,7 @@ static val static_slot_ens_rec(val stype, val sym, val newval,
     uw_throwf(error_s, lit("~a: ~s isn't a valid slot name"),
               self, sym, nao);
 
-  no_error_p = default_bool_arg(no_error_p);
+  no_error_p = default_null_arg(no_error_p);
 
   if (st->eqmslot == coerce(struct stslot *, -1))
     st->eqmslot = 0;
@@ -1129,7 +1129,7 @@ val static_slot_ensure(val stype, val sym, val newval, val no_error_p)
     trace_check(name);
   }
 
-  no_error_p = default_bool_arg(no_error_p);
+  no_error_p = default_null_arg(no_error_p);
   return static_slot_ens_rec(stype, sym, newval, no_error_p, self, 0);
 }
 
diff --git a/sysif.c b/sysif.c
index 9be964ed..d19c041d 100644
--- a/sysif.c
+++ b/sysif.c
@@ -112,7 +112,7 @@ static val at_exit_list;
 static val errno_wrap(val newval)
 {
   val oldval = num(errno);
-  if (default_bool_arg(newval))
+  if (default_null_arg(newval))
     errno = c_num(newval);
   return oldval;
 }
@@ -558,7 +558,7 @@ static val dup_wrap(val old, val neu)
 
 val exec_wrap(val file, val args_opt)
 {
-  val args = default_bool_arg(args_opt);
+  val args = default_null_arg(args_opt);
   int nargs = c_num(length(args)) + 1;
   char **argv = coerce(char **, chk_malloc((nargs + 1) * sizeof *argv));
   val iter;
diff --git a/unwind.c b/unwind.c
index cbbdf70a..dc883396 100644
--- a/unwind.c
+++ b/unwind.c
@@ -344,7 +344,7 @@ static val uw_find_frames_impl(val extype, val frtype, val just_one)
   uw_frtype_t et;
   list_collect_decl (out, ptail);
 
-  extype = default_bool_arg(extype);
+  extype = default_null_arg(extype);
   frtype = default_arg_strict(frtype, catch_frame_type);
 
   if (symbolp(frtype)) {
@@ -987,7 +987,7 @@ val uw_capture_cont(val tag, val fun, val ctx_form)
       break;
     case UW_GUARD:
       {
-        val sym = or2(car(default_bool_arg(ctx_form)), sys_capture_cont_s);
+        val sym = or2(car(default_null_arg(ctx_form)), sys_capture_cont_s);
         eval_error(ctx_form, lit("~s: cannot capture continuation "
                                  "spanning external library stack frames"),
                    sym, nao);
@@ -1000,7 +1000,7 @@ val uw_capture_cont(val tag, val fun, val ctx_form)
   }
 
   if (!fr) {
-    val sym = or2(car(default_bool_arg(ctx_form)), sys_capture_cont_s);
+    val sym = or2(car(default_null_arg(ctx_form)), sys_capture_cont_s);
 
     if (tag)
       eval_error(ctx_form, lit("~s: no block ~s is visible"), sym, tag, nao);