Fix type check for flags when only one is present

When only one flag is specified, it's parsed as an IdentValue rather
than a FlagsValue, so IdentValue needs to be able to type check flags
(aka bitfields) properly.

Fixes #47

blueprintcompiler/language/values.py

@@ -129,7 +129,7 @@ class IdentValue(Value):
     def validate_for_type(self):
         type = self.parent.value_type
 
-        if isinstance(type, gir.Enumeration):
+        if isinstance(type, gir.Enumeration) or isinstance(type, gir.Bitfield):
             if self.tokens["value"] not in type.members:
                 raise CompileError(
                     f"{self.tokens['value']} is not a member of {type.full_name}",

tests/samples/flags.blp

@@ -4,3 +4,7 @@ using Gio 2.0;
 Gio.Application {
   flags: is_service | handles_open;
 }
+
+EventControllerScroll {
+  flags: vertical;
+}

tests/samples/flags.ui

@@ -4,4 +4,7 @@
   <object class="GApplication">
     <property name="flags">is_service|handles_open</property>
   </object>
+  <object class="GtkEventControllerScroll">
+    <property name="flags">vertical</property>
+  </object>
 </interface>