The _FILE_ word returns nil when the source is a string or the console.

integration/compile_lib_tests.rb

@@ -181,7 +181,7 @@ class CompileLibraryTester < Minitest::Test
   end
 
   def test_for_FILE_method
-    foorth_equal('_FILE_', ['A string.'])
+    foorth_equal('_FILE_', [nil])
 
     nm = File.absolute_path('integration/_FILE_test.foorth')
     foorth_equal('"integration/_FILE_test.foorth" .load ', [nm, 7, nm])

lib/fOOrth/compiler/source/console.rb

@@ -64,7 +64,10 @@ module XfOOrth
       "The console."
     end
 
-    alias :file_name :source_name
+    #The console has no file name to return.
+    def fine_name
+      nil
+    end
 
   end
 end

lib/fOOrth/compiler/source/string_source.rb

@@ -21,7 +21,10 @@ module XfOOrth
       "A string."
     end
 
-    alias :file_name :source_name
+    #A string source has no file name to return.
+    def file_name
+      nil
+    end
 
   end