Improve compatibility with lua 5.2.

src/core/org/luaj/vm2/LuaClosure.java

@@ -560,5 +560,10 @@ public class LuaClosure extends LuaFunction {
 	protected void setUpvalue(int i, LuaValue v) {
 		upValues[i].setValue(v);
 	}
+
+	public String name() {
+		return "<"+p.shortsource()+":"+p.linedefined+">";
+	}
+	
 	
 }

src/core/org/luaj/vm2/LuaFunction.java

@@ -77,4 +77,11 @@ public class LuaFunction extends LuaValue {
 		String s = getClass().getName();
 		return s.substring(Math.max(s.lastIndexOf('.'),s.lastIndexOf('$'))+1);
 	}
+	
+	/** Return a human-readable name for this function.  Returns the last part of the class name by default.
+	 * Is overridden by LuaClosure to return the source file and line, and by LibFunctions to return the name.
+	 * @return common name for this function.  */
+	public String name() {
+		return classnamestub();
+	}
 }

src/core/org/luaj/vm2/Prototype.java

@@ -79,4 +79,13 @@ public class Prototype {
 	  }
 	  return null;  /* not found */
 	}
+	
+	public String shortsource() {
+		String name = source.tojstring();
+        if ( name.startsWith("@") || name.startsWith("=") )
+			name = name.substring(1);
+		else if ( name.startsWith("\033") )
+			name = "binary string";
+        return name;
+	}
 }

src/core/org/luaj/vm2/lib/DebugLib.java

@@ -467,13 +467,13 @@ public class DebugLib extends OneArgFunction {
 				this.linedefined = p.linedefined;
 				this.lastlinedefined = p.lastlinedefined;
 				this.what = (this.linedefined == 0) ? "main" : "Lua";
-				this.short_src = DebugLib.shortsource(p);
+				this.short_src = p.shortsource();
 			} else {
 				this.source = "=[Java]";
 				this.linedefined = -1;
 				this.lastlinedefined = -1;
 				this.what = "Java";
-				this.short_src = f.classnamestub();
+				this.short_src = f.name();
 			}
 		}
 	}
@@ -598,9 +598,6 @@ public class DebugLib extends OneArgFunction {
 				    			  ar.name = nw.name;
 				    			  ar.namewhat = nw.namewhat;
 				    		  }
-			    		  } else {
-			    			  ar.name = ci.previous.f.classnamestub();
-			    			  ar.namewhat = "Java";
 			    		  }
 			    	  }
 			    	  if (ar.namewhat == null) {
@@ -635,7 +632,7 @@ public class DebugLib extends OneArgFunction {
 			this.stack = stack;
 		}
 		public String shortsource() {
-			return f.isclosure()? DebugLib.shortsource(f.checkclosure().p): "[Java]";
+			return f.isclosure()? f.checkclosure().p.shortsource(): "[Java]";
 		}
 		void set(LuaFunction function) {
 			this.f = function;
@@ -675,7 +672,7 @@ public class DebugLib extends OneArgFunction {
 		}
 		String sourceline() {
 			if ( !f.isclosure() ) return f.tojstring();
-			return DebugLib.shortsource(f.checkclosure().p) + ":" + currentline();
+			return f.checkclosure().p.shortsource() + ":" + currentline();
 		}
 		private int linedefined() {
 			return f.isclosure()? f.checkclosure().p.linedefined: -1;
@@ -696,15 +693,6 @@ public class DebugLib extends OneArgFunction {
 		return null;
 	}
 	
-	public static String shortsource(Prototype p) {
-		String name = p.source.tojstring();
-        if ( name.startsWith("@") || name.startsWith("=") )
-			name = name.substring(1);
-		else if ( name.startsWith("\033") )
-			name = "binary string";
-        return name;
-	}
-	
 	static void lua_assert(boolean x) {
 		if (!x) throw new RuntimeException("lua_assert failed");
 	}