fix path issues when opening files

git-svn-id: https://yap.svn.sf.net/svnroot/yap/trunk@2137 b08c6af1-5177-4d33-ba66-4b1c6b8b522a

C/iopreds.c

@@ -2239,17 +2239,17 @@ p_open (void)
     Yap_Error(DOMAIN_ERROR_IO_MODE, t2, "open/3");
     return(FALSE);   
   }
-  if (!Yap_TrueFileName (RepAtom (AtomOfTerm (file_name))->StrOfAE, Yap_FileNameBuf, FALSE))
-    return (PlIOError (EXISTENCE_ERROR_SOURCE_SINK,file_name,"open/3"));
-  sno = GetFreeStreamD();
-  if (sno < 0)
-    return (PlIOError (SYSTEM_ERROR,TermNil, "new stream not available for open/3"));
-  st = &Stream[sno];
   /* can never happen */
   topts = Deref(ARG4);
   if (IsVarTerm(topts) || !IsIntegerTerm(topts))
     return(FALSE);
   opts = IntegerOfTerm(topts);
+  if (!strncpy(Yap_FileNameBuf, RepAtom (AtomOfTerm (file_name))->StrOfAE, YAP_FILENAME_MAX))
+    return (PlIOError (SYSTEM_ERROR,file_name,"file name is too long in open/3"));
+  sno = GetFreeStreamD();
+  if (sno < 0)
+    return (PlIOError (SYSTEM_ERROR,TermNil, "new stream not available for open/3"));
+  st = &Stream[sno];
   /* can never happen */
   tenc = Deref(ARG5);
   if (IsVarTerm(tenc) || !IsIntegerTerm(tenc))
@@ -4309,7 +4309,7 @@ p_get (void)
 
 static Int
 p_get0 (void)
-{				/* '$get0'(Stream,-N)                    */
+{				/* get0(Stream,-N)                    */
   int sno = CheckStream (ARG1, Input_Stream_f, "get0/2");
   Int status;
   Int out;
@@ -6014,8 +6014,8 @@ Yap_InitIOPreds(void)
   Yap_InitCPred ("$close", 1, p_close, SafePredFlag|SyncPredFlag|HiddenPredFlag);
   Yap_InitCPred ("flush_output", 1, p_flush, SafePredFlag|SyncPredFlag);
   Yap_InitCPred ("$flush_all_streams", 0, p_flush_all_streams, SafePredFlag|SyncPredFlag|HiddenPredFlag);
-  Yap_InitCPred ("$get", 2, p_get, SafePredFlag|SyncPredFlag|HiddenPredFlag);
+  Yap_InitCPred ("get", 2, p_get, SafePredFlag|SyncPredFlag|HiddenPredFlag);
-  Yap_InitCPred ("$get0", 2, p_get0, SafePredFlag|SyncPredFlag|HiddenPredFlag);
+  Yap_InitCPred ("get0", 2, p_get0, SafePredFlag|SyncPredFlag|HiddenPredFlag);
   Yap_InitCPred ("$get0_line_codes", 2, p_get0_line_codes, SafePredFlag|SyncPredFlag|HiddenPredFlag);
   Yap_InitCPred ("$get_byte", 2, p_get_byte, SafePredFlag|SyncPredFlag|HiddenPredFlag);
   Yap_InitCPred ("$access", 1, p_access, SafePredFlag|SyncPredFlag|HiddenPredFlag);

C/sysbits.c

@@ -1589,13 +1589,14 @@ Yap_volume_header(char *file)
   return volume_header(file);
 }
 
+/******
+      TODO: rewrite to use wordexp
+ ****/
 static int
 TrueFileName (char *source, char *root, char *result, int in_lib)
 {
-  register int ch;
+  char *res0 = result, *work;
-  register char *res0 = result, *work;
+  char ares1[YAP_FILENAME_MAX];
-  char ares1[YAP_FILENAME_MAX], *res1 = ares1;
-  char *var_name;
 
   result[0] = '\0';
 #if defined(__MINGW32__) || _MSC_VER
@@ -1610,149 +1611,137 @@ TrueFileName (char *source, char *root, char *result, int in_lib)
   }
 #endif
   /* step 1: eating home information */
-  if (source[0] == '~')
+  if (source[0] == '~') {
-    {
+    if (dir_separator(source[1]) || source[1] == '\0')
-      if (dir_separator(source[1]) || source[1] == '\0')
+      {
-	{
+	char *s;
-	  char *s;
+	source++;
-	  source++;
 #if defined(_WIN32)
-	  s = getenv("HOMEDRIVE");
+	s = getenv("HOMEDRIVE");
-	  if (s != NULL)
+	if (s != NULL)
-	    strncpy (result, getenv ("HOMEDRIVE"), YAP_FILENAME_MAX);
+	  strncpy (result, getenv ("HOMEDRIVE"), YAP_FILENAME_MAX);
-	  s = getenv("HOMEPATH");
+	s = getenv("HOMEPATH");
-	  if (s != NULL)
+	if (s != NULL)
-	    strncpy (result, s, YAP_FILENAME_MAX);
+	  strncpy (result, s, YAP_FILENAME_MAX);
 #else
-	  s = getenv ("HOME");
+	s = getenv ("HOME");
-	  if (s != NULL)
+	if (s != NULL)
-	    strncpy (result, s, YAP_FILENAME_MAX);
+	  strncpy (result, s, YAP_FILENAME_MAX);
 #endif
-	}
+      } else {
 #if HAVE_GETPWNAM
-      else
+      struct passwd *user_passwd;
-	{
-	  struct passwd *user_passwd;
 
-	  source++;
+      source++;
-	  while (!dir_separator((*res0 = *source)) && *res0 != '\0')
+      while (!dir_separator((*res0 = *source)) && *res0 != '\0')
-	    res0++, source++;
+	res0++, source++;
-	  *res0++ = '\0';
+      *res0++ = '\0';
-	  if ((user_passwd = getpwnam (result)) == NULL)
+      if ((user_passwd = getpwnam (result)) == NULL) {
-	    {
+	return FALSE;
-	      return(FALSE);
+      }
-	    }
+      strncpy (result, user_passwd->pw_dir, YAP_FILENAME_MAX);
-	  strncpy (result, user_passwd->pw_dir, YAP_FILENAME_MAX);
+#else
-	}
+      return FALSE;
 #endif
-      strncat (result, source, YAP_FILENAME_MAX);
     }
-  else
+    strncat (result, source, YAP_FILENAME_MAX);
+  } else if (source[0] == '$') {
+    /* follow SICStus expansion rules */
+    int ch;
+    char *s;
+    char *res0 = source+1;
+
+    while ((ch = *res0) && is_valid_env_char (ch)) {
+      res0++;
+    }
+    *res0 = '\0';
+    if (!(s = (char *) getenv (source+1))) {
+      return FALSE;
+    }
+    *res0 = ch;
+    strncpy (result, s, YAP_FILENAME_MAX);
+    strncat (result, res0, YAP_FILENAME_MAX);
+  } else {
     strncpy (result, source, YAP_FILENAME_MAX);
-  /* step 2: handling environment variables in file names */
+  }
-  strncpy (ares1, result, YAP_FILENAME_MAX);
+#if defined(_WIN32)
-  res0 = result;
+  res1 = result;
-  while ((ch = *res1++)!=0)
+  /* step 2 WINDOWS: replacing \ by / */
-    {
+  while ((ch = *res1++)) {
-      if (ch == '\\' && !dir_separator('\\'))
+    if (ch == '\\' && dir_separator('\\')) {
-	{
+      res1[-1] = '/';
-	  ch = *res1++;
-	  if (ch == '\0')
-	    {
-	      *res0 = '\0';
-	      break;
-	    }
-	  else
-	    *res0++ = ch;
-	}
-      if (ch != '$')
-	*res0++ = ch;
-      else
-	{
-	  char env_var[256], *sptr = env_var;
-	  while (((ch = *res1)!=0) && is_valid_env_char (ch))
-	    {
-	      res1++;
-	      *sptr++ = ch;
-	    }
-	  *sptr = '\0';
-	  if ((var_name = (char *) getenv (env_var)) == NULL)
-	    {
-	      return(FALSE);
-	    }
-	  else
-	    while ((*res0 = *var_name++)!=0)
-	      res0++;
-	}
     }
-  *res0 = '\0';
+  }
+#endif
   /* step 3: get the full file name */
   if (!dir_separator(result[0]) && !volume_header(result)) {
-    if (root) {
-      strncpy(ares1, root, YAP_FILENAME_MAX);
-#if _MSC_VER || defined(__MINGW32__)
-      strncat (ares1, "\\", YAP_FILENAME_MAX);
-#else
-      strncat (ares1, "/", YAP_FILENAME_MAX);
-#endif
-      strncat (ares1, result, YAP_FILENAME_MAX);
-    } else {
 #if __simplescalar__
-      /* does not implement getcwd */
+    /* does not implement getcwd */
-      strncpy(ares1,yap_pwd,YAP_FILENAME_MAX);
+    strncpy(ares1,yap_pwd,YAP_FILENAME_MAX);
 #elif HAVE_GETCWD
-      if (getcwd (ares1, YAP_FILENAME_MAX) == NULL)
+    if (getcwd (ares1, YAP_FILENAME_MAX) == NULL)
-	return FALSE;
+      return FALSE;
 #else
-      if (getwd (ares1) == NULL)
+    if (getwd (ares1) == NULL)
-	return FALSE;
+      return FALSE;
 #endif
+#if _MSC_VER || defined(__MINGW32__)
+    strncat (ares1, "\\", YAP_FILENAME_MAX);
+#else
+    strncat (ares1, "/", YAP_FILENAME_MAX);
+#endif
+    if (root) {
+      if (!dir_separator(root[0]) && !volume_header(root)) {
+	strncat(ares1, root, YAP_FILENAME_MAX);
+      } else {
+	strncpy(ares1, root, YAP_FILENAME_MAX);
+      }
 #if _MSC_VER || defined(__MINGW32__)
       strncat (ares1, "\\", YAP_FILENAME_MAX);
 #else
       strncat (ares1, "/", YAP_FILENAME_MAX);
 #endif
-      strncat (ares1, result, YAP_FILENAME_MAX);
+    }
-      if (in_lib) {
+    strncat (ares1, result, YAP_FILENAME_MAX);
-	int tmpf;
+    if (in_lib) {
-	if ((tmpf = open(ares1, O_RDONLY)) < 0) {
+      int tmpf;
-	    /* not in current directory, let us try the library */
+      if ((tmpf = open(ares1, O_RDONLY)) < 0) {
-	  if  (Yap_LibDir != NULL) {
+	/* not in current directory, let us try the library */
-	    strncpy(Yap_FileNameBuf, Yap_LibDir, YAP_FILENAME_MAX);
+	if  (Yap_LibDir != NULL) {
+	  strncpy(Yap_FileNameBuf, Yap_LibDir, YAP_FILENAME_MAX);
 #if HAVE_GETENV
-	  } else {
-	    char *yap_env = getenv("YAPLIBDIR");
-	    if (yap_env != NULL) {
-	      strncpy(ares1, yap_env, YAP_FILENAME_MAX);
-#endif
-	    } else {
-#if _MSC_VER || defined(__MINGW32__)
-	      if (libdir)
-		strncpy(ares1, libdir, YAP_FILENAME_MAX);
-	      else
-#endif
-		strncpy(ares1, LIB_DIR, YAP_FILENAME_MAX);
-	    }
-#if HAVE_GETENV
-	  }
-#endif
-#if _MSC_VER || defined(__MINGW32__)
-	  strncat(ares1,"\\", YAP_FILENAME_MAX);
-#else
-	  strncat(ares1,"/", YAP_FILENAME_MAX);
-#endif
-	  strncat(ares1,result, YAP_FILENAME_MAX);
-	  if ((tmpf = open(ares1, O_RDONLY)) >= 0) {
-	    close(tmpf);
-	    strncpy (result, ares1, YAP_FILENAME_MAX);
-	  }
 	} else {
-	  strncpy (result, ares1, YAP_FILENAME_MAX);
+	  char *yap_env = getenv("YAPLIBDIR");
+	  if (yap_env != NULL) {
+	    strncpy(ares1, yap_env, YAP_FILENAME_MAX);
+#endif
+	  } else {
+#if _MSC_VER || defined(__MINGW32__)
+	    if (libdir)
+	      strncpy(ares1, libdir, YAP_FILENAME_MAX);
+	    else
+#endif
+	      strncpy(ares1, LIB_DIR, YAP_FILENAME_MAX);
+	  }
+#if HAVE_GETENV
+	}
+#endif
+#if _MSC_VER || defined(__MINGW32__)
+	strncat(ares1,"\\", YAP_FILENAME_MAX);
+#else
+	strncat(ares1,"/", YAP_FILENAME_MAX);
+#endif
+	strncat(ares1,result, YAP_FILENAME_MAX);
+	if ((tmpf = open(ares1, O_RDONLY)) >= 0) {
 	  close(tmpf);
+	  strncpy (result, ares1, YAP_FILENAME_MAX);
 	}
       } else {
 	strncpy (result, ares1, YAP_FILENAME_MAX);
+	close(tmpf);
       }
+    } else {
+      strncpy (result, ares1, YAP_FILENAME_MAX);
     }
   }
   /* step 4: simplifying the file name */

H/iopreds.h

@@ -126,6 +126,8 @@ StreamDesc;
 #define RepError_Prolog_f	0x400000
 #define RepError_Xml_f		0x800000
 
+#define EXPAND_FILENAME		0x000080
+
 #define StdInStream	0
 #define StdOutStream	1
 #define	StdErrStream	2

changes-5.1.html

@@ -17,7 +17,10 @@ xb
 
 <h2>Yap-5.1.3:</h2>
 <ul>
-<li> FIXED: [   ] should be processed by parser, not by scanner (obs
+<li> FIXED: true_file_name/3 was totally broken (obs from Nicos Agelopoulos).</li>
+<li> FIXED: Environment variables should only be seen at the beginning
+  of the file (obs from Samir Genaim.)</li> 
+<li> FIXED: [ ] should be processed by parser, not by scanner (obs
   from Samir Genaim).</li>
 <li> NEW: file_base_name/2.</li>
 <li> FIXED: in console, count input characters as being output, as they

docs/yap.tex

@@ -4047,6 +4047,16 @@ escape code or @code{xml} (write @code{&#...;} XML character entity).
 The initial mode is @code{prolog} for the user streams and
 @code{error} for all other streams. See also @ref{Encoding}.
 
+@item expand_filename(+@var{Mode})
+If @var{Mode} is @code{true} then do filename expansion, then ask Prolog
+to do file name expansion before actually trying to opening the file:
+this includes processing @code{~} characters and processing @code{$}
+environment variables at the beginning of the file. Otherwise, just try
+to open the file using the given name.
+
+The default behavior is given by the Prolog flag
+@code{open_expands_filename}.
+
 @end table
 
 @item close(+@var{S}) [ISO]
@@ -7616,6 +7626,13 @@ blackboard when the key is an integer.
 Read or set the size of the hash table that is used for looking up the
 internal data-base when the key is an integer.
 
+@item open_expands_filename
+@findex open_expands_filename (yap_flag/2 option)
+@*
+If @code{true} the @code{open/3} builtin performs filename-expansion
+before opening a file (SICStus Prolog like). If @code{false} it does not
+(SWI-Prolog like).
+
 @item  profiling
 @findex profiling (yap_flag/2 option)
 @*

library/lists.yap

@@ -95,25 +95,6 @@ last([], Last, Last).
 last([H|List], _, Last) :-
 	last(List, H, Last).
 
-%   member(?Element, ?Set)
-%   is true when Set is a list, and Element occurs in it.  It may be used
-%   to test for an element or to enumerate all the elements by backtracking.
-%   Indeed, it may be used to generate the Set!
-
-member(Element, [Element|_]).
-member(Element, [_|Rest]) :-
-        member(Element, Rest).
-
-
-%   memberchk(+Element, +Set)
-%   means the same thing, but may only be used to test whether a known
-%   Element occurs in a known Set.  In return for this limited use, it
-%   is more efficient when it is applicable.
-
-memberchk(Element, [Element|_]) :- !.
-memberchk(Element, [_|Rest]) :-
-        memberchk(Element, Rest).
-
 %   nextto(X, Y, List)
 %   is true when X and Y appear side-by-side in List.  It could be written as
 %	nextto(X, Y, List) :- append(_, [X,Y,_], List).

library/swi.yap

@@ -5,6 +5,8 @@
 
 :- yap_flag(unknown,error).
 
+:- yap_flag(open_expands_filename,false).
+
 % redefines stuff in prolog module.
 
 :- module(swi, []).

pl/boot.yap

@@ -65,6 +65,7 @@ true :- true.
 	prompt('  ?- '),
 	nb_setval('$break',0),
 	% '$set_read_error_handler'(error), let the user do that
+	nb_setval('$open_expands_filename',true),
 	nb_setval('$debug',off),
 	nb_setval('$trace',off),
 	b_setval('$spy_glist',[]),
@@ -532,7 +533,7 @@ true :- true.
 
 '$another' :-
 	format(user_error,' ? ',[]),
-	'$get0'(user_input,C),
+	get0(user_input,C),
 	(   C== 0'; ->  '$skip'(user_input,10), %'
 	    '$add_nl_outside_console',
 	    fail

pl/directives.yap

@@ -436,13 +436,13 @@ yap_flag(float_min_exponent,X) :-
 yap_flag(float_epsilon,X) :-
 	'$do_error'(domain_error(flag_value,float_min_exponent+X),yap_flag(float_min_exponent,X)).
 
-yap_flag(float_max_exponent,X) :-
+yap_flag(float_max_exponent,X) :-
 	var(X), !,
 	?????
-yap_flag(float_max_exponent,X) :-
+yap_flag(float_max_exponent,X) :-
 	integer(X), X > 0, !,
 	'$do_error'(permission_error(modify,flag,float_max_exponent),yap_flag(float_max_exponent,X)).
-yap_flag(float_max_exponent,X) :-
+yap_flag(float_max_exponent,X) :-
 	'$do_error'(domain_error(flag_value,float_max_exponent+X),yap_flag(float_max_exponent,X)).
 */
 
@@ -580,6 +580,12 @@ yap_flag(chr_toplevel_show_store,X) :-
 yap_flag(chr_toplevel_show_store,X) :-
 	'$do_error'(domain_error(flag_value,chr_toplevel_show_store+X),yap_flag(chr_toplevel_show_store,X)).
 
+yap_flag(open_expands_filename,Expand) :-
+	var(Expand), !,
+	'$default_expand'(Expand).
+yap_flag(open_expands_filename,Expand) :-
+	'$set_default_expand'(Expand).
+
 yap_flag(single_var_warnings,X) :-
 	var(X), !,
 	('$syntax_check_mode'(on,_), '$syntax_check_single_var'(on,_) ->
@@ -810,6 +816,10 @@ yap_flag(dialect,yap).
 %		V = fast  ;
 		V = fileerrors  ;
 		V = float_format ;
+%		V = float_mantissa_digits ;
+%		V = float_epsilon ;
+%		V = float_min_exponent ;
+%		V = float_max_exponent ;
 		V = gc    ;
 		V = gc_margin    ;
 		V = gc_trace     ;
@@ -828,11 +838,8 @@ yap_flag(dialect,yap).
 		V = max_threads ;
 		V = min_integer ;
 		V = min_tagged_integer ;
-%		V = float_mantissa_digits ;
-%		V = float_epsilon ;
-%		V = float_min_exponent ;
-%		V = float_max_exponent ;
 		V = n_of_integer_keys_in_db ;
+		V = open_expands_filename ;
 		V = profiling ;
 		V = redefine_warnings ;
 		V = shared_object_search_path ;

pl/modules.yap

@@ -134,7 +134,7 @@ module(N) :-
 	'$use_preds'(P,Publics,Mod,M),
 	'$use_preds'(Ps,Publics,Mod,M).
 '$use_preds'(N/K,Publics,M,Mod) :-
-    (  '$member'(N/K,Publics) -> true ;
+    (  lists:memberchk(N/K,Publics) -> true ;
 	print_message(warning,import(N/K,Mod,M,private))
     ),
     '$do_import'(N, K, M, Mod).
@@ -469,8 +469,23 @@ current_module(Mod,TFN) :-
 source_module(Mod) :-
 	'$current_module'(Mod).
 
-'$member'(X,[X|_]) :- !.
+%   member(?Element, ?Set)
-'$member'(X,[_|L]) :- '$member'(X,L).
+%   is true when Set is a list, and Element occurs in it.  It may be used
+%   to test for an element or to enumerate all the elements by backtracking.
+%   Indeed, it may be used to generate the Set!
+
+lists:memberchk(X,[X|_]) :- !.
+lists:memberchk(X,[_|L]) :-
+	lists:memberchk(X,L).
+
+%   memberchk(+Element, +Set)
+%   means the same thing, but may only be used to test whether a known
+%   Element occurs in a known Set.  In return for this limited use, it
+%   is more efficient when it is applicable.
+
+lists:member(X,[X|_]) :- !.
+lists:member(X,[_|L]) :-
+	lists:member(X,L).
 
 
 % comma has its own problems.
@@ -639,20 +654,20 @@ abolish_module(_).
 
 '$clean_conversion'([], _, [], [], _).
 '$clean_conversion'([P1|Ps], List, [P1-P1|Tab], [P1|MyExports], Goal) :-
-	'$member'(P1, List), !,
+	lists:memberchk(P1, List), !,
 	'$clean_conversion'(Ps, List, Tab, MyExports, Goal).
 '$clean_conversion'([(N1/A1 as N2)|Ps], List, [N1/A1-N2/A1|Tab], [N2/A1|MyExports], Goal) :-
-	'$member'(N1/A1, List), !,
+	lists:memberchk(N1/A1, List), !,
 	'$clean_conversion'(Ps, List, Tab, MyExports, Goal).
 '$clean_conversion'([P|_], _, _, _, Goal) :-
 	'$do_error'(domain_error(module_reexport_predicates,P), Goal).
 	
 '$neg_conversion'([], _, [], [], _).
 '$neg_conversion'([P1|Ps], List, Tab, MyExports, Goal) :-
-	'$member'(P1, List), !,
+	lists:memberchk(P1, List), !,
 	'$neg_conversion'(Ps, List, Tab, MyExports, Goal).
 '$neg_conversion'([N1/A1|Ps], List, [N1/A1-N2/A1|Tab], [N2/A1|MyExports], Goal) :-
-	'$member'(N1/A1 as N2, List), !,
+	lists:memberchk(N1/A1 as N2, List), !,
 	'$neg_conversion'(Ps, List, Tab, MyExports, Goal).
 '$neg_conversion'([P|Ps], List, [P-P|Tab], [P|MyExports], Goal) :-
 	'$neg_conversion'(Ps, List, Tab, MyExports, Goal).

pl/preds.yap

@@ -852,7 +852,7 @@ predicate_property(Pred,Prop) :-
 '$predicate_property'(P,M,M,exported) :-
 	functor(P,N,A),
 	recorded('$module','$module'(_TFN,M,Publics),_),
-	'$member'(N/A,Publics), !.	/* defined in modules.yap */
+	lists:memberchk(N/A,Publics), !.
 '$predicate_property'(P,Mod,_,number_of_clauses(NCl)) :-
 	'$number_of_clauses'(P,Mod,NCl).
 

pl/yio.yap

@@ -23,8 +23,10 @@ open(Source,M,T) :- var(M), !,
 	'$do_error'(instantiation_error,open(Source,M,T)).
 open(Source,M,T) :- nonvar(T), !,
 	'$do_error'(type_error(variable,T),open(Source,M,T)).
-open(File,Mode,Stream) :-
+open(File0,Mode,Stream) :-
 	'$default_encoding'(Encoding),
+	'$default_expand'(Expansion),	
+	'$expand_filename'(Expansion, File0, File),
 	'$open'(File,Mode,Stream,16,Encoding).
 
 /* meaning of flags for '$write' is
@@ -59,11 +61,16 @@ close(S,Opts) :-
 	
 open(F,T,S,Opts) :-
 	'$check_io_opts'(Opts,open(F,T,S,Opts)),
-	'$process_open_opts'(Opts, 0, N,  Aliases, E, BOM),
+	'$process_open_opts'(Opts, 0, N,  Aliases, E, BOM, Expand),
-	'$open2'(F,T,S,N,E),
+	'$expand_filename'(Expand, F, NF),
+	'$open2'(NF, T, S, N, E),
 	'$process_bom'(S, BOM),
 	'$process_open_aliases'(Aliases,S).
 
+'$expand_filename'(false, F, F) :- !.
+'$expand_filename'(true, F, NF) :-
+	system:true_file_name(F, NF).
+
 '$open2'(Source,M,T,N,_) :- var(Source), !,
 	'$do_error'(instantiation_error,open(Source,M,T,N)).
 '$open2'(Source,M,T,N,_) :- var(M), !,
@@ -83,26 +90,30 @@ open(F,T,S,Opts) :-
 	'$add_alias_to_stream'(Alias, S),
 	'$process_open_aliases'(Aliases,S).
 
-'$process_open_opts'([], N, N, [], DefaultEncoding, []) :-
+'$process_open_opts'([], N, N, [], DefaultEncoding, [], DefaultExpand) :-
-	'$default_encoding'(DefaultEncoding).
+	'$default_encoding'(DefaultEncoding),
-'$process_open_opts'([type(T)|L], N0, N, Aliases, Encoding, BOM) :-
+	'$default_expand'(DefaultExpand).
+'$process_open_opts'([type(T)|L], N0, N, Aliases, Encoding, BOM, DefaultExpand) :-
 	'$value_open_opt'(T,type,I1,I2),
 	N1 is I1\/N0,
 	N2 is I2/\N1,
-	'$process_open_opts'(L,N2,N, Aliases, Encoding, BOM).
+	'$process_open_opts'(L,N2,N, Aliases, Encoding, BOM, DefaultExpand).
-'$process_open_opts'([reposition(T)|L], N0, N, Aliases, Encoding, BOM) :-
+'$process_open_opts'([expand_filename(T)|L], N0, N, Aliases, Encoding, BOM, Expand) :-
+	'$valid_expand'(T, Expand),
+	'$process_open_opts'(L,N2,N, Aliases, Encoding, BOM, _).
+'$process_open_opts'([reposition(T)|L], N0, N, Aliases, Encoding, BOM, DefaultExpand) :-
 	'$value_open_opt'(T,reposition,I1,I2),
 	N1 is I1\/N0,
 	N2 is I2/\N1,
-	'$process_open_opts'(L,N2,N, Aliases, Encoding, BOM).
+	'$process_open_opts'(L,N2,N, Aliases, Encoding, BOM, DefaultExpand).
-'$process_open_opts'([encoding(Enc)|L], N0, N, Aliases, EncCode, BOM) :-
+'$process_open_opts'([encoding(Enc)|L], N0, N, Aliases, EncCode, BOM, DefaultExpand) :-
 	'$valid_encoding'(Enc, EncCode),
-	'$process_open_opts'(L, N0, N, Aliases, _, BOM).
+	'$process_open_opts'(L, N0, N, Aliases, _, BOM, DefaultExpand).
-'$process_open_opts'([representation_errors(Mode)|L], N0, N, Aliases, EncCode, BOM) :-
+'$process_open_opts'([representation_errors(Mode)|L], N0, N, Aliases, EncCode, BOM, DefaultExpand) :-
 	'$valid_reperrorhandler'(Mode, Flag),
 	NI is N0 \/ Flag,
-	'$process_open_opts'(L, NI, N, Aliases, EncCode, BOM).
+	'$process_open_opts'(L, NI, N, Aliases, EncCode, BOM, DefaultExpand).
-'$process_open_opts'([bom(BOM)|L], N0, N, Aliases, EncCode, BOM) :-
+'$process_open_opts'([bom(BOM)|L], N0, N, Aliases, EncCode, BOM, DefaultExpand) :-
 	(
 	 var(BOM)
 	->
@@ -111,14 +122,14 @@ open(F,T,S,Opts) :-
 	 '$valid_bom'(BOM, Flag),
 	 NI is N0 \/ Flag
 	),
-	'$process_open_opts'(L, NI, N, Aliases, EncCode, _).
+	'$process_open_opts'(L, NI, N, Aliases, EncCode, _, DefaultExpand).
-'$process_open_opts'([eof_action(T)|L], N0, N, Aliases, Encoding, BOM) :-
+'$process_open_opts'([eof_action(T)|L], N0, N, Aliases, Encoding, BOM, DefaultExpand) :-
 	'$value_open_opt'(T,eof_action,I1,I2),
 	N1 is I1\/N0,
 	N2 is I2/\N1,
-	'$process_open_opts'(L,N2,N, Aliases, Encoding, BOM).
+	'$process_open_opts'(L,N2,N, Aliases, Encoding, BOM, DefaultExpand).
-'$process_open_opts'([alias(Alias)|L], N0, N, [Alias|Aliases], Encoding, BOM) :-
+'$process_open_opts'([alias(Alias)|L], N0, N, [Alias|Aliases], Encoding, BOM, DefaultExpand) :-
-	'$process_open_opts'(L,N0,N, Aliases, Encoding, BOM).
+	'$process_open_opts'(L,N0,N, Aliases, Encoding, BOM, DefaultExpand).
 
 
 '$value_open_opt'(text,_,1,X) :- X is 128-2. % default
@@ -140,6 +151,9 @@ open(F,T,S,Opts) :-
 '$valid_reperrorhandler'(prolog, 512).
 '$valid_reperrorhandler'(xml, 1024).
 
+'$valid_expand'(true, true),
+'$valid_expand'(false, false),
+
 /* check whether a list of options is valid */
 '$check_io_opts'(V,G) :- var(V), !,
 	'$do_error'(instantiation_error,G).
@@ -587,7 +601,7 @@ print(_,_).
 
 /* character I/O	*/
 
-get(N) :- current_input(S), '$get'(S,N).
+get(N) :- current_input(S), get(S,N).
 
 get_byte(V) :-
 	\+ var(V), (\+ integer(V) ; V < -1 ; V > 256), !,
@@ -621,7 +635,7 @@ get_char(V) :-
 	'$do_error'(type_error(in_character,V),get_char(V)).
 get_char(V) :-
 	current_input(S),
-	'$get0'(S,I),
+	get0(S,I),
 	( I = -1 -> V = end_of_file ; atom_codes(V,[I])).
 
 get_char(S,V) :-
@@ -629,7 +643,7 @@ get_char(S,V) :-
 	( atom(V)  -> atom_codes(V,[_,_|_]), V \= end_of_file ; true ), !,
 	'$do_error'(type_error(in_character,V),get_char(S,V)).
 get_char(S,V) :-
-	'$get0'(S,I),
+	get0(S,I),
 	( I = -1 -> V = end_of_file ; atom_codes(V,[I])).
 
 peek_char(V) :-
@@ -653,14 +667,14 @@ get_code(S,V) :-
 	\+ var(V), (\+ integer(V)), !,
 	'$do_error'(type_error(in_character_code,V),get_code(S,V)).
 get_code(S,V) :-
-	'$get0'(S,V).
+	get0(S,V).
 
 get_code(V) :-
 	\+ var(V), (\+ integer(V)), !,
 	'$do_error'(type_error(in_character_code,V),get_code(V)).
 get_code(V) :-
 	current_input(S),
-	'$get0'(S,V).
+	get0(S,V).
 
 peek_code(S,V) :-
 	\+ var(V), (\+ integer(V)), !,
@@ -732,11 +746,7 @@ put_code(S,V) :-
 
 
 
-get(Stream,N) :- '$get'(Stream,N).
+get0(N) :- current_input(S), get0(S,N).
-
-get0(N) :- current_input(S), '$get0'(S,N).
-
-get0(Stream,N) :- '$get0'(Stream,N).
 
 put(N) :- current_output(S),  N1 is N, '$put'(S,N1).
 
@@ -759,9 +769,9 @@ tab(_).
 tab(Stream,N) :- '$tab'(Stream,N), fail.
 tab(_,_).
 
-ttyget(N) :- '$get'(user_input,N).
+ttyget(N) :- get(user_input,N).
 
-ttyget0(N) :- '$get0'(user_input,N).
+ttyget0(N) :- get0(user_input,N).
 
 ttyskip(N) :-  N1 is N, '$skip'(user_input,N1).
 
@@ -1070,3 +1080,12 @@ stream_position_data(line_position, '$stream_position'(_,_,Data,_,_), Data).
 %stream_position_data(char_count, '$stream_position'(Data,_,_,_,_), Data).
 stream_position_data(byte_count, '$stream_position'(Data,_,_,_,_), Data).
 
+'$default_expand'(Expand) :-
+	nb_getval('$open_expands_filename',Expand).
+
+'$set_default_expand'(true) :- !,
+	nb_setval('$open_expands_filename',true).
+'$set_default_expand'(false) :- !,
+	nb_setval('$open_expands_filename',false).
+'$set_default_expand'(V) :- !,
+	'$do_error'(domain_error(flag_value,V),yap_flag(open_expands_file_name,X)).