diff --git a/C/arith0.c b/C/arith0.c
index fce74e9d3..7d8a023aa 100644
--- a/C/arith0.c
+++ b/C/arith0.c
@@ -111,7 +111,7 @@ static char     SccsId[] = "%W% %G%";
 #include "Yap.h"
 #include "Yatom.h"
 #include "YapHeap.h"
-#include "eval.h"
+#include "YapEval.h"
 
 
 
diff --git a/C/arith1.c b/C/arith1.c
index 0c7d45798..abaab04cc 100644
--- a/C/arith1.c
+++ b/C/arith1.c
@@ -228,7 +228,7 @@ X is Y*10+C-48.
 #include "Yap.h"
 #include "Yatom.h"
 #include "YapHeap.h"
-#include "eval.h"
+#include "YapEval.h"
 
 static Term
 float_to_int(Float v USES_REGS)
diff --git a/C/arith2.c b/C/arith2.c
index ddce481a5..5a26fced4 100644
--- a/C/arith2.c
+++ b/C/arith2.c
@@ -127,7 +127,7 @@ These are the binary numeric operators currently supported by YAP.
 #include "Yap.h"
 #include "Yatom.h"
 #include "YapHeap.h"
-#include "eval.h"
+#include "YapEval.h"
 
 #include "arith2.h"
 
diff --git a/C/arrays.c b/C/arrays.c
index f621bd075..eb219ad3c 100644
--- a/C/arrays.c
+++ b/C/arrays.c
@@ -102,7 +102,7 @@ The following predicates manipulate arrays:
 #include "Yap.h"
 #include "Yatom.h"
 #include "clause.h"
-#include "eval.h"
+#include "YapEval.h"
 #include "heapgc.h"
 #if HAVE_ERRNO_H
 #include <errno.h>
diff --git a/C/bignum.c b/C/bignum.c
index f0a7b0367..3da5acf1d 100644
--- a/C/bignum.c
+++ b/C/bignum.c
@@ -30,7 +30,7 @@ static char     SccsId[] = "%W% %G%";
 
 #ifdef USE_GMP
 
-#include "eval.h"
+#include "YapEval.h"
 #include "alloc.h"
 
 Term
diff --git a/C/cmppreds.c b/C/cmppreds.c
index 9da40cd5b..faa0970c5 100644
--- a/C/cmppreds.c
+++ b/C/cmppreds.c
@@ -57,7 +57,7 @@ static char SccsId[] = "%W% %G%";
 #include "Yap.h"
 #include "YapHeap.h"
 #include "Yatom.h"
-#include "eval.h"
+#include "YapEval.h"
 #if HAVE_STRING_H
 #include <string.h>
 #endif
diff --git a/C/compiler.c b/C/compiler.c
index bffd9ab19..04bbe70b6 100644
--- a/C/compiler.c
+++ b/C/compiler.c
@@ -174,7 +174,7 @@ static char SccsId[] = "%W% %G%";
 #include "Yap.h"
 #include "alloc.h"
 #include "clause.h"
-#include "compile.h"
+#include "YapCompile.h"
 #include "yapio.h"
 #if HAVE_STRING_H
 #include <string.h>
diff --git a/C/computils.c b/C/computils.c
index 82b4e1189..3bf9ab27a 100644
--- a/C/computils.c
+++ b/C/computils.c
@@ -54,13 +54,13 @@ static char SccsId[] = "%W% %G%";
 
 /*
  * This file includes a set of utilities, useful to the several compilation
- * modules 
+ * modules
  */
 
 #include "Yap.h"
 #include "Yatom.h"
 #include "YapHeap.h"
-#include "compile.h"
+#include "YapCompile.h"
 #include "yapio.h"
 #if HAVE_STRING_H
 #include <string.h>
@@ -69,7 +69,7 @@ static char SccsId[] = "%W% %G%";
 
 /*
  * The compiler creates an instruction chain which will be assembled after
- * afterwards 
+ * afterwards
  */
 
 
@@ -146,7 +146,7 @@ AllocCMem (UInt size, struct intermediates *cip)
     LOCAL_Error_Size = 256+((char *)cip->freep - (char *)HR);
     save_machine_regs();
     siglongjmp(cip->CompilerBotch, OUT_OF_STACK_BOTCH);
-  } 
+  }
   p = cip->freep;
   cip->freep += size;
   return p;
@@ -216,7 +216,7 @@ is_a_test(Term arg, Term mod)
 	  return TRUE;
 	}
 	return FALSE;
-      }      
+      }
       return pe->PredFlags & (TestPredFlag|BinaryPredFlag);
     }
   }
@@ -315,7 +315,7 @@ Yap_emit_6ops (compiler_vm_op o, CELL r1, CELL r2, CELL r3, CELL r4, CELL r5, CE
   p->rnd1 = r1;
   p->rnd2 = r2;
   p->rnd3 = r3;
-  p->rnd4 = r4; 
+  p->rnd4 = r4;
   p->rnd5 = r5;
   p->rnd6 = r6;
   p->nextInst = NIL;
@@ -337,7 +337,7 @@ Yap_emit_7ops (compiler_vm_op o, CELL r1, CELL r2, CELL r3, CELL r4, CELL r5, CE
   p->rnd1 = r1;
   p->rnd2 = r2;
   p->rnd3 = r3;
-  p->rnd4 = r4; 
+  p->rnd4 = r4;
   p->rnd5 = r5;
   p->rnd6 = r6;
   p->rnd7 = r7;
@@ -520,7 +520,7 @@ write_special_label(special_label_op arg, special_label_id rn, UInt lab)
       Yap_DebugErrorPuts("fail");
       break;
     }
-  }    
+  }
 }
 
 static void
@@ -616,7 +616,7 @@ ShowOp (compiler_vm_op ic, const char *f, struct PSEUDO *cpc)
 		Yap_DebugPlWrite(MkIntegerTerm((Int)(*ptr++)));
 	      }
 	    }
-	    break;		
+	    break;
 	  case 'l':
 	    write_address (arg);
 	    break;
@@ -645,7 +645,7 @@ ShowOp (compiler_vm_op ic, const char *f, struct PSEUDO *cpc)
             Yap_DebugPlWrite (MkIntTerm ((v->NoOfVE) & MaskVarAdrs));
           }
 	    }
-	    break;	
+	    break;
 	  case 'N':
 	    {
 	      Ventry *v;
@@ -795,4 +795,3 @@ Yap_ShowCode (struct intermediates *cint)
 }
 
 #endif /* DEBUG */
-
diff --git a/C/depth_bound.c b/C/depth_bound.c
index b9e253dfd..a920542fd 100644
--- a/C/depth_bound.c
+++ b/C/depth_bound.c
@@ -22,7 +22,7 @@ static char     SccsId[] = "%W% %G%";
 
 #include "Yap.h"
 #include "Yatom.h"
-#include "eval.h"
+#include "YapEval.h"
 
 #ifdef DEPTH_LIMIT
 
diff --git a/C/eval.c b/C/eval.c
index b4c08d13d..a16a4916b 100644
--- a/C/eval.c
+++ b/C/eval.c
@@ -31,7 +31,7 @@ static char SccsId[] = "%W% %G%";
 
 #include "YapHeap.h"
 #include "Yatom.h"
-#include "eval.h"
+#include "YapEval.h"
 #if HAVE_STDARG_H
 #include <stdarg.h>
 #endif
diff --git a/C/exo.c b/C/exo.c
index 9bbe6ad82..eb4354ee7 100755
--- a/C/exo.c
+++ b/C/exo.c
@@ -21,7 +21,7 @@
 #include "Yap.h"
 #include "clause.h"
 #include "yapio.h"
-#include "eval.h"
+#include "YapEval.h"
 #include "tracer.h"
 #ifdef YAPOR
 #include "or.macros.h"
diff --git a/C/exo_udi.c b/C/exo_udi.c
index 741277e45..90a9cf382 100755
--- a/C/exo_udi.c
+++ b/C/exo_udi.c
@@ -20,7 +20,7 @@
 #include "Yap.h"
 #include "clause.h"
 #include "yapio.h"
-#include "eval.h"
+#include "YapEval.h"
 #include "tracer.h"
 #include "attvar.h"
 #ifdef YAPOR
diff --git a/C/flags.c b/C/flags.c
index fa1b553e6..0e62684ee 100644
--- a/C/flags.c
+++ b/C/flags.c
@@ -60,7 +60,7 @@ static Int current_prolog_flag(USES_REGS1);
 static Int set_prolog_flag(USES_REGS1);
 
 #include "Yatom.h"
-#include "eval.h"
+#include "YapEval.h"
 #include "yapio.h"
 
 #define YAP_FLAG(ID, NAME, WRITABLE, DEF, INIT, HELPER)                        \
diff --git a/C/gmp_support.c b/C/gmp_support.c
index 167802cb1..a1f7e506f 100644
--- a/C/gmp_support.c
+++ b/C/gmp_support.c
@@ -18,7 +18,7 @@
 #include "Yap.h"
 #include "Yatom.h"
 #include "YapHeap.h"
-#include "eval.h"
+#include "YapEval.h"
 #if HAVE_STRING_H
 #include <string.h>
 #endif
diff --git a/C/grow.c b/C/grow.c
index 13e30ad11..cbd532665 100755
--- a/C/grow.c
+++ b/C/grow.c
@@ -20,7 +20,7 @@
 #include "yapio.h"
 #include "alloc.h"
 #include "sshift.h"
-#include "compile.h"
+#include "YapCompile.h"
 #include "attvar.h"
 #include "cut_c.h"
 #if HAVE_STRING_H
diff --git a/C/index.c b/C/index.c
index 7722ab2f3..6fd571344 100755
--- a/C/index.c
+++ b/C/index.c
@@ -634,7 +634,7 @@ type_of_verb(rest,passive).
  */
 
 #include "absmi.h"
-#include "compile.h"
+#include "YapCompile.h"
 #if DEBUG
 #include "yapio.h"
 #endif
diff --git a/C/mavar.c b/C/mavar.c
index 3ce613ba8..135fff36e 100644
--- a/C/mavar.c
+++ b/C/mavar.c
@@ -48,7 +48,7 @@ deterministic computations.
 
 #include "Yatom.h"
 #include "YapHeap.h"
-#include "eval.h"
+#include "YapEval.h"
 
 static Int p_setarg( USES_REGS1 );
 static Int p_create_mutable( USES_REGS1 );
diff --git a/C/parser.c b/C/parser.c
index e4001d273..fde6b32e2 100755
--- a/C/parser.c
+++ b/C/parser.c
@@ -141,7 +141,7 @@ dot with single quotes.
 #include "YapHeap.h"
 #include "YapText.h"
 #include "Yatom.h"
-#include "eval.h"
+#include "YapEval.h"
 #include "yapio.h"
 /* stuff we want to use in standard YAP code */
 #include "iopreds.h"
diff --git a/C/range.c b/C/range.c
index 378621347..71c0efd94 100644
--- a/C/range.c
+++ b/C/range.c
@@ -21,7 +21,7 @@ static char     SccsId[] = "%W% %G%";
 #include "Yap.h"
 #include "Yatom.h"
 #include "YapHeap.h"
-#include "eval.h"
+#include "YapEval.h"
 
 static Int
 p_in_range( USES_REGS1 ) {
diff --git a/C/scanner.c b/C/scanner.c
index 122c35f82..0b3b2570c 100755
--- a/C/scanner.c
+++ b/C/scanner.c
@@ -407,7 +407,7 @@ writing, writing a BOM can be requested using the option
 #include "YapHeap.h"
 #include "Yatom.h"
 #include "alloc.h"
-#include "eval.h"
+#include "YapEval.h"
 #include "yapio.h"
 /* stuff we want to use in standard YAP code */
 #include "YapText.h"
diff --git a/C/signals.c b/C/signals.c
index cdc3f36cd..b2684b519 100755
--- a/C/signals.c
+++ b/C/signals.c
@@ -30,7 +30,7 @@ static char SccsId[] = "%W% %G%";
 #endif
 #include "YapHeap.h"
 #include "Yatom.h"
-#include "eval.h"
+#include "YapEval.h"
 #include "yapio.h"
 #ifdef TABLING
 #include "tab.macros.h"
diff --git a/C/stack.c b/C/stack.c
index e8a6ec09e..c1bb25b7a 100644
--- a/C/stack.c
+++ b/C/stack.c
@@ -30,7 +30,7 @@
 
 #include "Yap.h"
 #include "clause.h"
-#include "eval.h"
+#include "YapEval.h"
 #include "iopreds.h"
 #include "tracer.h"
 #include "yapio.h"
diff --git a/C/stackinfo.c b/C/stackinfo.c
index 10a7c7ce6..b61621b4b 100644
--- a/C/stackinfo.c
+++ b/C/stackinfo.c
@@ -31,7 +31,7 @@
 #include "Yap.h"
 #include "clause.h"
 #include "yapio.h"
-#include "eval.h"
+#include "YapEval.h"
 #include "tracer.h"
 #ifdef YAPOR
 #include "or.macros.h"
diff --git a/C/stdpreds.c b/C/stdpreds.c
index e62665634..d019f7821 100755
--- a/C/stdpreds.c
+++ b/C/stdpreds.c
@@ -37,7 +37,7 @@ static char SccsId[] = "%W% %G%";
 #include "Foreign.h"
 #include "YapHeap.h"
 #include "Yatom.h"
-#include "eval.h"
+#include "YapEval.h"
 #include "yapio.h"
 #ifdef TABLING
 #include "tab.macros.h"
diff --git a/C/text.c b/C/text.c
index 648ca6c2a..7ffd2eba8 100644
--- a/C/text.c
+++ b/C/text.c
@@ -16,10 +16,10 @@
 *************************************************************************/
 
 #include "Yap.h"
+#include "YapEval.h"
 #include "YapHeap.h"
 #include "YapText.h"
 #include "Yatom.h"
-#include "eval.h"
 #include "yapio.h"
 
 #include <YapText.h>
diff --git a/C/threads.c b/C/threads.c
index f875530f1..96f51175e 100644
--- a/C/threads.c
+++ b/C/threads.c
@@ -26,7 +26,7 @@ static char     SccsId[] = "%W% %G%";
 #include "Yap.h"
 #include "Yatom.h"
 #include "YapHeap.h"
-#include "eval.h"
+#include "YapEval.h"
 #include "yapio.h"
 #include "blobs.h"
 #include <stdio.h>
diff --git a/os/alias.c b/os/alias.c
index 267e488dc..cd70f62fd 100644
--- a/os/alias.c
+++ b/os/alias.c
@@ -61,7 +61,7 @@ static char SccsId[] = "%W% %G%";
 #include "Yatom.h"
 #include "YapHeap.h"
 #include "yapio.h"
-#include "eval.h"
+#include "YapEval.h"
 #include "YapText.h"
 #include <stdlib.h>
 #if HAVE_STDARG_H
diff --git a/os/chartypes.c b/os/chartypes.c
index f7019b3b9..1e61250fc 100644
--- a/os/chartypes.c
+++ b/os/chartypes.c
@@ -74,7 +74,7 @@ static char SccsId[] = "%W% %G%";
 #define S_ISDIR(x) (((x)&_S_IFDIR) == _S_IFDIR)
 #endif
 #endif
-#include "eval.h"
+#include "YapEval.h"
 #include "iopreds.h"
 
 static Int p_change_type_of_char(USES_REGS1);
diff --git a/os/format.c b/os/format.c
index 6e5517971..105faab12 100644
--- a/os/format.c
+++ b/os/format.c
@@ -263,7 +263,7 @@ output is directed to the stream used by format/2.
 #endif
 #endif
 
-#include "eval.h"
+#include "YapEval.h"
 #include "iopreds.h"
 #include "format.h"
 
diff --git a/os/iopreds.c b/os/iopreds.c
index 316c7b99d..7ef1e1c18 100644
--- a/os/iopreds.c
+++ b/os/iopreds.c
@@ -36,7 +36,7 @@ static char SccsId[] = "%W% %G%";
 #include "YapHeap.h"
 #include "YapText.h"
 #include "Yatom.h"
-#include "eval.h"
+#include "YapEval.h"
 #include "yapio.h"
 #include <stdlib.h>
 #if HAVE_UNISTD_H
diff --git a/os/streams.c b/os/streams.c
index bfb356f05..3d31b4bf7 100644
--- a/os/streams.c
+++ b/os/streams.c
@@ -32,7 +32,7 @@ static char SccsId[] = "%W% %G%";
 #include "YapHeap.h"
 #include "YapText.h"
 #include "Yatom.h"
-#include "eval.h"
+#include "YapEval.h"
 #include "yapio.h"
 #include <stdlib.h>
 #if HAVE_STDARG_H
diff --git a/os/sysbits.c b/os/sysbits.c
index c5a8ee9c0..8a2ffcac3 100644
--- a/os/sysbits.c
+++ b/os/sysbits.c
@@ -65,7 +65,7 @@ void Yap_WinError(char *yap_error) {
   /* Error, we could not read time */
   FormatMessage(FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS,
                 NULL, GetLastError(), MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
-                msg, 256, NULL);
+                msg, 255, NULL);
   Yap_Error(SYSTEM_ERROR_OPERATING_SYSTEM, TermNil, "%s at %s", msg, yap_error);
 }
 #endif /* __WINDOWS__ */
@@ -81,7 +81,7 @@ static bool is_directory(const char *FileName) {
   if ((vfs = vfs_owner(FileName))) {
     return vfs->isdir(vfs, FileName);
   }
-#ifdef __WINDOWS__
+#ifdef _WIN32
   DWORD dwAtts = GetFileAttributes(FileName);
   if (dwAtts == INVALID_FILE_ATTRIBUTES)
     return false;
@@ -952,15 +952,15 @@ static bool initSysPath(Term tlib, Term tcommons, bool dir_done,
   {
     char *dir;
     if ((dir = Yap_RegistryGetString("library")) && is_directory(dir)) {
+      dir_done = true;
       if (!Yap_unify(tlib, MkAtomTerm(Yap_LookupAtom(dir))))
         return FALSE;
     }
-    dir_done = true;
     if ((dir = Yap_RegistryGetString("prolog_commons")) && is_directory(dir)) {
       if (!Yap_unify(tcommons, MkAtomTerm(Yap_LookupAtom(dir))))
         return FALSE;
+      commons_done = true;
     }
-    commons_done = true;
   }
   if (dir_done && commons_done)
     return TRUE;
@@ -1199,9 +1199,7 @@ const char *Yap_findFile(const char *isource, const char *idef,
         source = (isource ? isource : idef);
       }
       if (source) {
-        if (source[0] == '/') {
-          abspath = true;
-        }
+          abspath = Yap_IsAbsolutePath(source);
       }
       if (!abspath && !root && ftype == YAP_BOOT_PL) {
         root = YAP_PL_SRCDIR;
@@ -1251,7 +1249,7 @@ const char *Yap_findFile(const char *isource, const char *idef,
       break;
 
     case 4: // WIN stuff: registry
-#if __WINDOWS__
+#if __WINDOWS
       if (in_lib) {
         source = (ftype == YAP_PL || ftype == YAP_QLY ? "library" : "startup");
         source = Yap_RegistryGetString(source);
diff --git a/os/sysbits.h b/os/sysbits.h
index f1bbe6307..8253b1a73 100644
--- a/os/sysbits.h
+++ b/os/sysbits.h
@@ -25,7 +25,7 @@
 #include "YapHeap.h"
 #include "YapText.h"
 #include "Yatom.h"
-#include "eval.h"
+#include "YapEval.h"
 #include "yapio.h"
 
 // Win32 InputOutput Support
diff --git a/os/writeterm.c b/os/writeterm.c
index 16f943073..0c385c79a 100644
--- a/os/writeterm.c
+++ b/os/writeterm.c
@@ -28,7 +28,7 @@ static char SccsId[] = "%W% %G%";
 #include "YapHeap.h"
 #include "YapText.h"
 #include "Yatom.h"
-#include "eval.h"
+#include "YapEval.h"
 #include "yapio.h"
 #include <stdlib.h>
 #if HAVE_STDARG_H