struct variable type checking, refactoring to avoid circular dependencies

src/Ubc/Parse/Scope.hs

@@ -0,0 +1,16 @@
+module Ubc.Parse.Scope
+( Scope(..)
+, expectScopeStruct
+)
+where
+
+import Ubc.Parse.Scope.FileScope (FileScope)
+import Ubc.Parse.Scope.StructScope (StructScope)
+
+data Scope = 
+          ScopeFile FileScope
+        | ScopeStruct StructScope
+
+expectScopeStruct :: Scope -> StructScope
+expectScopeStruct (ScopeStruct s) = s
+expectScopeStruct _               = error "Internal Error: Top Scope is not Scope Struct"