diff --git a/vhdlpp/expression_elaborate.cc b/vhdlpp/expression_elaborate.cc
index 4c64ff186..5f54fc66a 100644
--- a/vhdlpp/expression_elaborate.cc
+++ b/vhdlpp/expression_elaborate.cc
@@ -1027,19 +1027,18 @@ const VType* ExpName::probe_type(Entity*ent, ScopeBase*scope) const
         if (Variable*var = scope->find_variable(name_))
                 return var->peek_type();
 
-        const VType*ctype = 0;
+        const VType*type = 0;
         Expression*cval = 0;
-        if (scope->find_constant(name_, ctype, cval))
-                return ctype;
+        if (scope->find_constant(name_, type, cval))
+                return type;
 
-        const VType*gtype = 0;
         Architecture*arc = dynamic_cast<Architecture*>(scope);
-        if (arc && (gtype = arc->probe_genvar_type(name_))) {
-                return gtype;
+        if (arc && (type = arc->probe_genvar_type(name_))) {
+                return type;
         }
 
-        if (scope->is_enum_name(name_)) {
-            return &primitive_INTEGER;
+        if ((type = scope->is_enum_name(name_))) {
+            return type;
         }
       }
 
diff --git a/vhdlpp/library.cc b/vhdlpp/library.cc
index 61ae426df..fda670a34 100644
--- a/vhdlpp/library.cc
+++ b/vhdlpp/library.cc
@@ -404,11 +404,19 @@ void generate_global_types(ActiveScope*res)
       res->use_name(perm_string::literal("real"),      &primitive_REAL);
       res->use_name(perm_string::literal("std_logic"), &primitive_STDLOGIC);
       res->use_name(perm_string::literal("character"), &primitive_CHARACTER);
-      res->use_name(perm_string::literal("bit_vector"),&primitive_BOOL_VECTOR);
+      res->use_name(perm_string::literal("bit_vector"),&primitive_BIT_VECTOR);
       res->use_name(perm_string::literal("string"),    &primitive_STRING);
       res->use_name(perm_string::literal("natural"),   &primitive_NATURAL);
 }
 
+void emit_std_types(ostream&out)
+{
+    out << "`ifndef __VHDL_STD_TYPES" << endl;
+    out << "`define __VHDL_STD_TYPES" << endl;
+    out << "typedef enum bit { \\false , \\true } boolean ;" << endl;
+    out << "`endif" << endl;
+}
+
 bool is_global_type(perm_string name)
 {
       if (name == "boolean") return true;
diff --git a/vhdlpp/library.h b/vhdlpp/library.h
index ab6464f45..fe04aad23 100644
--- a/vhdlpp/library.h
+++ b/vhdlpp/library.h
@@ -26,6 +26,7 @@ extern void library_add_directory(const char*directory);
 
 extern Subprogram*library_find_subprogram(perm_string name);
 
+extern void emit_std_types(ostream&out);
 extern int emit_packages(void);
 
 #endif /* IVL_library_H */
diff --git a/vhdlpp/main.cc b/vhdlpp/main.cc
index b142d3845..418e73daa 100644
--- a/vhdlpp/main.cc
+++ b/vhdlpp/main.cc
@@ -232,6 +232,8 @@ int main(int argc, char*argv[])
 	    return 3;
       }
 
+      emit_std_types(cout);
+
       errors = emit_packages();
       if (errors > 0) {
 	    fprintf(stderr, "%d errors emitting packages.\n", errors);
diff --git a/vhdlpp/scope.cc b/vhdlpp/scope.cc
index 0682a45d0..49b422e89 100644
--- a/vhdlpp/scope.cc
+++ b/vhdlpp/scope.cc
@@ -188,15 +188,15 @@ Subprogram* ScopeBase::find_subprogram(perm_string name) const
       return 0;
 }
 
-bool ScopeBase::is_enum_name(perm_string name) const
+const VTypeEnum* ScopeBase::is_enum_name(perm_string name) const
 {
     for(list<const VTypeEnum*>::const_iterator it = use_enums_.begin();
             it != use_enums_.end(); ++it) {
         if((*it)->has_name(name))
-            return true;
+            return *it;
     }
 
-    return false;
+    return NULL;
 }
 
 /*
diff --git a/vhdlpp/scope.h b/vhdlpp/scope.h
index 69e859fb9..709e552ec 100644
--- a/vhdlpp/scope.h
+++ b/vhdlpp/scope.h
@@ -58,7 +58,9 @@ class ScopeBase {
       Variable* find_variable(perm_string by_name) const;
       virtual const InterfacePort* find_param(perm_string by_name) const;
       Subprogram* find_subprogram(perm_string by_name) const;
-      bool is_enum_name(perm_string name) const;
+	// Checks if a string is one of possible enum values. If so, the enum
+	// type is returned, otherwise NULL.
+      const VTypeEnum* is_enum_name(perm_string name) const;
 
 	// Moves signals, variables and components from another scope to
 	// this one. After the transfer new_* maps are cleared in the source scope.
diff --git a/vhdlpp/vtype_emit.cc b/vhdlpp/vtype_emit.cc
index 64577e004..b97d00d7e 100644
--- a/vhdlpp/vtype_emit.cc
+++ b/vhdlpp/vtype_emit.cc
@@ -149,8 +149,10 @@ int VTypePrimitive::emit_primitive_type(ostream&out) const
       int errors = 0;
       switch (type_) {
 	  case BOOLEAN:
+	    out << "boolean";
+	    break;
 	  case BIT:
-	    out << "bool";
+	    out << "bit";
 	    break;
 	  case STDLOGIC:
 	    out << "logic";