ADDED: write_term/2: option radix(Radix).

Experimental.  Under discussion as PIP-105.  The current implementation
writes, unlike XSB, the radix prefix.  We either need more options
or we should consider another alternative such as integer_format(+Format)

As this patch cleans up a lot of the code regarding numeric output and
most will be needed anyway, it is merged despite the fact that the
radix option may vanish eventually.

src/ATOMS

@@ -403,6 +403,7 @@ A heap_gc		"heap_gc"
 A heapused		"heapused"
 A heartbeat		"heartbeat"
 A help			"help"
+A hex			"hex"
 A hidden		"hidden"
 A hide_childs		"hide_childs"
 A history_depth		"history_depth"
@@ -594,6 +595,7 @@ A numbervars		"numbervars"
 A numerator		"numerator"
 A obfuscate		"obfuscate"
 A occurs_check		"occurs_check"
+A octal			"octal"
 A octet		        "octet"
 A off			"off"
 A offset		"offset"

src/os/pl-fmt.c

@@ -51,14 +51,13 @@ source should also use format() to produce error messages, etc.
 #include <stdio.h>
 #include <math.h>
 #include <fenv.h>
+#include "pl-fmt.h"
 #ifdef __WINDOWS__
 #include "../pl-nt.h"
 #endif
 
 typedef foreign_t (*Func1)(term_t a1);
 
-static char *	formatInteger(PL_locale *locale, int div, int radix,
-			     bool smll, Number n, Buffer out);
 static char *	formatFloat(PL_locale *locale, int how, int arg,
 			    Number f, Buffer out);
 
@@ -1052,7 +1051,15 @@ revert_string(char *s, size_t len)
   }
 }
 
-static char *
+/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+Format the integer  `i` to the buffer `out`.  `div`  is for supporting
+fixed point numbers.   `radix` is the base and  `smll` defines whether
+to use capitals (`false`) or  lowercase letters for digit values above
+9.
+- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
+
+
+char *
 formatInteger(PL_locale *locale, int div, int radix, bool smll, Number i,
 	     Buffer out)
 { const char *grouping = NULL;
@@ -1725,12 +1732,24 @@ formatFloat(PL_locale *locale, int how, int arg, Number f, Buffer out)
       int size = 0;
 
       if ( how == 'h' || how == 'H' )
-      { if ( !growBuffer(out, 100) )
-	{ PL_no_memory();
-	  return NULL;
+      { size_t space = 32;
+
+	for(int n=0; n<2; n++)
+	{ size_t sz;
+
+	  if ( !growBuffer(out, space) )
+	  { PL_no_memory();
+	    return NULL;
+	  }
+	  sz = format_float(out->base, space, f->value.f,
+			    arg, how == 'H' ? 'E' : 'e');
+	  if ( sz < space )
+	  { written = sz;
+	    break;
+	  } else
+	  { space = sz+1;
+	  }
 	}
-	format_float(f->value.f, arg, how == 'H' ? 'E' : 'e', out->base);
-	written = strlen(out->base);
       } else
       { Ssprintf(tmp, "%%.%d%c", arg, how);
 	while(written >= size)

src/os/pl-fmt.h

@@ -0,0 +1,43 @@
+/*  Part of SWI-Prolog
+
+    Author:        Jan Wielemaker
+    E-mail:        J.Wielemaker@vu.nl
+    WWW:           http://www.swi-prolog.org
+    Copyright (c)  2024, University of Amsterdam
+                         VU University Amsterdam
+		         CWI, Amsterdam
+    All rights reserved.
+
+    Redistribution and use in source and binary forms, with or without
+    modification, are permitted provided that the following conditions
+    are met:
+
+    1. Redistributions of source code must retain the above copyright
+       notice, this list of conditions and the following disclaimer.
+
+    2. Redistributions in binary form must reproduce the above copyright
+       notice, this list of conditions and the following disclaimer in
+       the documentation and/or other materials provided with the
+       distribution.
+
+    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+    "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+    LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+    FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+    COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+    INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+    BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+    LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+    CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+    LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+    ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+    POSSIBILITY OF SUCH DAMAGE.
+*/
+
+#ifndef FMT_H_INCLUDED
+#define FMT_H_INCLUDED
+
+COMMON(char *)	formatInteger(PL_locale *locale, int div, int radix,
+			      bool smll, Number n, Buffer out);
+
+#endif /*FMT_H_INCLUDED*/

src/os/pl-text.c

@@ -282,11 +282,23 @@ PL_get_text(DECL_LD term_t l, PL_chars_t *text, int flags)
     text->encoding  = ENC_ISO_LATIN_1;
     text->canonical = true;
   } else if ( (flags & CVT_FLOAT) && isFloat(w) )
-  { format_float(valFloat(w), 3, 'e', text->buf);
-    text->text.t    = text->buf;
-    text->length    = strlen(text->text.t);
+  { size_t sz = format_float(text->buf, sizeof(text->buf),
+			     valFloat(w), 3, 'e');
+    if ( sz < sizeof(text->buf) )
+    { text->text.t    = text->buf;
+      text->length    = sz;
+      text->storage   = PL_CHARS_LOCAL;
+    } else
+    { Buffer b  = findBuffer(BUF_STACK);
+
+      if ( !growBuffer(b, sz+1) )
+	outOfCore();
+      format_float(b->base, sz+1, valFloat(w), 3, 'e');
+      text->text.t  = baseBuffer(b, char);
+      text->length  = sz;
+      text->storage = PL_CHARS_STACK;
+    }
     text->encoding  = ENC_ISO_LATIN_1;
-    text->storage   = PL_CHARS_LOCAL;
     text->canonical = true;
   } else if ( (flags & CVT_LIST) )
   { Buffer b;

src/pl-fli.c

@@ -787,14 +787,21 @@ static int	compareUCSAtom(atom_t h1, atom_t h2);
 static int	saveUCSAtom(atom_t a, IOSTREAM *fd);
 static atom_t	loadUCSAtom(IOSTREAM *fd);
 
+static int
+blob_write_usc_atom(IOSTREAM *fd, atom_t atom, int flags)
+{ bool rc = writeUCSAtom(fd, atom, flags);
+
+  return rc ? 1 : -1;
+}
+
 static PL_blob_t ucs_atom =
 { PL_BLOB_MAGIC,
   PL_BLOB_UNIQUE|PL_BLOB_TEXT|PL_BLOB_WCHAR,
 					/* unique representation of text */
   "ucs_text",
   NULL,					/* release */
   compareUCSAtom,			/* compare */
-  writeUCSAtom,				/* write */
+  blob_write_usc_atom,			/* write */
   NULL,					/* acquire */
   saveUCSAtom,				/* save load to/from .qlf files */
   loadUCSAtom

src/pl-ressymbol.c

@@ -3,7 +3,8 @@
     Author:        Jan Wielemaker
     E-mail:        J.Wielemaker@vu.nl
     WWW:           http://www.swi-prolog.org
-    Copyright (c)  2013-2017, VU University Amsterdam
+    Copyright (c)  2013-2024, VU University Amsterdam
+			      SWI-Prolog Solutions b.v.
     All rights reserved.
 
     Redistribution and use in source and binary forms, with or without
@@ -43,14 +44,21 @@
 
 static int	compareReservedSymbol(atom_t h1, atom_t h2);
 
+static int
+blob_write_reserved_symbol(IOSTREAM *fd, atom_t atom, int flags)
+{ bool rc = writeReservedSymbol(fd, atom, flags);
+
+  return rc ? 1 : -1;
+}
+
 static PL_blob_t reserved_symbol =
 { PL_BLOB_MAGIC,
   PL_BLOB_UNIQUE,
 					/* unique representation of text */
   "reserved_symbol",
   NULL,					/* release */
   compareReservedSymbol,		/* compare */
-  writeReservedSymbol,			/* write */
+  blob_write_reserved_symbol,		/* write */
   NULL,					/* acquire */
   NULL,					/* save load to/from .qlf files */
   NULL,