Define Prolog.BUILTIN constant for the builtin package

This string is used in a number of places, making it a constant
in the Prolog class alongside of Nil simplifies some code.

5 files changed, 8 insertions, 5 deletions

diff --git a/src/builtin/PRED_$call_2.java b/src/builtin/PRED_$call_2.java
index 802d8ab..32d3904 100644
--- a/src/builtin/PRED_$call_2.java
+++ b/src/builtin/PRED_$call_2.java
@@ -48,7 +48,7 @@ class PRED_$call_2 extends Predicate.P2 {
 	      return engine.pcl.predicate(((SymbolTerm)a1).name(), functor, cont, args);
 	    } catch (ExistenceException e) {
 		try {
-            return engine.pcl.predicate("com.googlecode.prolog_cafe.builtin", functor, cont, args);
+            return engine.pcl.predicate(Prolog.BUILTIN, functor, cont, args);
 		} catch (ExistenceException e2) {
 		    if ((engine.getUnknown()).equals("fail"))
 			return engine.fail();
diff --git a/src/builtin/PRED_$compiled_predicate_or_builtin_3.java b/src/builtin/PRED_$compiled_predicate_or_builtin_3.java
index 21aad62..d220849 100644
--- a/src/builtin/PRED_$compiled_predicate_or_builtin_3.java
+++ b/src/builtin/PRED_$compiled_predicate_or_builtin_3.java
@@ -20,7 +20,7 @@ public final class PRED_$compiled_predicate_or_builtin_3 extends Predicate.P3 {
         Term a2 = arg2.dereference();
         Term a3 = arg3.dereference();
         if(! engine.pcl.definedPredicate(((SymbolTerm)a1).name(), ((SymbolTerm)a2).name(), ((IntegerTerm)a3).intValue())
-        && ! engine.pcl.definedPredicate("com.googlecode.prolog_cafe.builtin", ((SymbolTerm)a2).name(), ((IntegerTerm)a3).intValue()))
+        && ! engine.pcl.definedPredicate(Prolog.BUILTIN, ((SymbolTerm)a2).name(), ((IntegerTerm)a3).intValue()))
           return engine.fail();
         return cont;
     }
diff --git a/src/lang/Prolog.java b/src/lang/Prolog.java
index 0c3e029..638703d 100644
--- a/src/lang/Prolog.java
+++ b/src/lang/Prolog.java
@@ -92,6 +92,9 @@ public final class Prolog {
     /** Hashtable for managing internal databases. */
     protected HashtableOfTerm hashManager;
 
+    /** Name of the builtin package. */
+    public static final String BUILTIN = "com.googlecode.prolog_cafe.builtin";
+
     /** Holds an atom <code>[]<code> (empty list). */
     public static final SymbolTerm Nil     = SymbolTerm.makeSymbol("[]");
 
diff --git a/src/lang/PrologControl.java b/src/lang/PrologControl.java
index cf7869b..91b1834 100644
--- a/src/lang/PrologControl.java
+++ b/src/lang/PrologControl.java
@@ -84,7 +84,7 @@ public abstract class PrologControl {
      * is set to the <code>cont</code> field of <code>call(t)</code> as continuation.
      */
     public void setPredicate(Term t)  {
-      setPredicate("com.googlecode.prolog_cafe.builtin", "call", t);
+      setPredicate(Prolog.BUILTIN, "call", t);
     }
 
     /**
diff --git a/src/lang/PrologMain.java b/src/lang/PrologMain.java
index a791965..bb0229d 100644
--- a/src/lang/PrologMain.java
+++ b/src/lang/PrologMain.java
@@ -41,14 +41,14 @@ public class PrologMain {
 	    } 
 	    Term arg1 = Prolog.Nil;
 	    arg1 = new ListTerm(SymbolTerm.makeSymbol("user"), arg1);
-	    arg1 = new ListTerm(SymbolTerm.makeSymbol("com.googlecode.prolog_cafe.builtin"), arg1);
+	    arg1 = new ListTerm(SymbolTerm.makeSymbol(Prolog.BUILTIN), arg1);
 	    Term arg2 = parseAtomicGoal(argv[0]);
 	    if (arg2  == null) {
 		usage();
 		System.exit(1);
 	    }
 	    p = new BlockingPrologControl();
-	    p.setPredicate("com.googlecode.prolog_cafe.builtin", "initialization", arg1, arg2);
+	    p.setPredicate(Prolog.BUILTIN, "initialization", arg1, arg2);
 	    for (boolean r = p.call(); r; r = p.redo()) {}
 	    System.exit(0);
 	} catch (Exception e){