diff --git a/vhdlpp/lexor_keyword.gperf b/vhdlpp/lexor_keyword.gperf
index 1b086f147..9ee02c5a9 100644
--- a/vhdlpp/lexor_keyword.gperf
+++ b/vhdlpp/lexor_keyword.gperf
@@ -49,6 +49,7 @@ error,		GN_KEYWORD_2008,	K_error
 exit,		GN_KEYWORD_2008,	K_exit
 failure,	GN_KEYWORD_2008,	K_failure
 fairness,	GN_KEYWORD_2008,	K_fairness
+false,		GN_KEYWORD_2008,	K_false
 file,		GN_KEYWORD_2008,	K_file
 for,		GN_KEYWORD_2008,	K_for
 force,		GN_KEYWORD_2008,	K_force
@@ -117,6 +118,7 @@ subtype,	GN_KEYWORD_2008,	K_subtype
 then,		GN_KEYWORD_2008,	K_then
 to,		GN_KEYWORD_2008,	K_to
 transport,	GN_KEYWORD_2008,	K_transport
+true,		GN_KEYWORD_2008,	K_true
 type,		GN_KEYWORD_2008,	K_type
 unaffected,	GN_KEYWORD_2008,	K_unaffected
 units,		GN_KEYWORD_2008,	K_units
diff --git a/vhdlpp/parse.y b/vhdlpp/parse.y
index 40121df37..34a352e40 100644
--- a/vhdlpp/parse.y
+++ b/vhdlpp/parse.y
@@ -272,7 +272,7 @@ static void touchup_interface_for_functions(std::list<InterfacePort*>*ports)
 %token K_case K_component K_configuration K_constant K_context K_cover
 %token K_default K_disconnect K_downto
 %token K_else K_elsif K_end K_entity K_error K_exit
-%token K_failure K_fairness K_file K_for K_force K_function
+%token K_failure K_fairness K_false K_file K_for K_force K_function
 %token K_generate K_generic K_group K_guarded
 %token K_if K_impure K_in K_inertial K_inout K_is
 %token K_label K_library K_linkage K_literal K_loop
@@ -285,7 +285,7 @@ static void touchup_interface_for_functions(std::list<InterfacePort*>*ports)
 %token K_restrict K_restrict_guarantee K_return K_reverse_range K_rol K_ror
 %token K_select K_sequence K_severity K_signal K_shared
 %token K_sla K_sll K_sra K_srl K_strong K_subtype
-%token K_then K_to K_transport K_type
+%token K_then K_to K_transport K_true K_type
 %token K_unaffected K_units K_until K_use
 %token K_variable K_vmode K_vprop K_vunit
 %token K_wait K_warning K_when K_while K_with
@@ -1827,6 +1827,17 @@ primary
 	delete[]$1;
 	$$ = tmp;
       }
+  | K_true
+      { ExpBitstring*tmp = new ExpBitstring("1");
+	FILE_NAME(tmp, @1);
+	$$ = tmp;
+      }
+  | K_false
+      { ExpBitstring*tmp = new ExpBitstring("0");
+	FILE_NAME(tmp, @1);
+	$$ = tmp;
+      }
+
 /*XXXX Caught up in element_association_list?
   | '(' expression ')'
       { $$ = $2; }