diff --git a/library/DataDefs.cpp b/library/DataDefs.cpp
index 5d2386282e..50be583459 100644
--- a/library/DataDefs.cpp
+++ b/library/DataDefs.cpp
@@ -232,8 +232,8 @@ const std::string df::buffer_container_identity::getFullName(const type_identity
 }
 
 union_identity::union_identity(size_t size, const TAllocateFn alloc,
-        compound_identity *scope_parent, const char *dfhack_name,
-        struct_identity *parent, const struct_field_info *fields)
+        const compound_identity *scope_parent, const char *dfhack_name,
+        const struct_identity *parent, const struct_field_info *fields)
     : struct_identity(size, alloc, scope_parent, dfhack_name, parent, fields)
 {
 }
@@ -350,7 +350,7 @@ virtual_identity *virtual_identity::find(void *vtable)
     return NULL;
 }
 
-void virtual_identity::adjust_vtable(virtual_ptr obj, virtual_identity *main)
+void virtual_identity::adjust_vtable(virtual_ptr obj, const virtual_identity *main) const
 {
     if (vtable_ptr) {
         *(void**)obj = vtable_ptr;
diff --git a/library/include/DataDefs.h b/library/include/DataDefs.h
index 76e74c9791..6a5695809d 100644
--- a/library/include/DataDefs.h
+++ b/library/include/DataDefs.h
@@ -326,8 +326,8 @@ namespace DFHack
     class DFHACK_EXPORT union_identity : public struct_identity {
     public:
         union_identity(size_t size, TAllocateFn alloc,
-                compound_identity *scope_parent, const char *dfhack_name,
-                struct_identity *parent, const struct_field_info *fields);
+                const compound_identity *scope_parent, const char *dfhack_name,
+                const struct_identity *parent, const struct_field_info *fields);
 
         virtual identity_type type() const { return IDTYPE_UNION; }
 
@@ -418,13 +418,13 @@ namespace DFHack
         template<class P> static P get_vmethod_ptr(P selector);
 
     public:
-        bool can_instantiate() { return can_allocate(); }
-        virtual_ptr instantiate() { return can_instantiate() ? (virtual_ptr)do_allocate() : NULL; }
+        bool can_instantiate() const { return can_allocate(); }
+        virtual_ptr instantiate() const { return can_instantiate() ? (virtual_ptr)do_allocate() : NULL; }
         static virtual_ptr clone(virtual_ptr obj);
 
     public:
         // Strictly for use in virtual class constructors
-        void adjust_vtable(virtual_ptr obj, virtual_identity *main);
+        void adjust_vtable(virtual_ptr obj, const virtual_identity *main) const;
     };
 
     template<class T>
@@ -536,10 +536,10 @@ namespace df
     struct identity_traits {};
 
     template<class T>
-        requires requires () { { &T::_identity } -> std::convertible_to<compound_identity*>; }
+        requires requires () { { &T::_identity } -> std::convertible_to<const compound_identity*>; }
     struct identity_traits<T> {
         static const bool is_primitive = false;
-        static compound_identity *get() { return &T::_identity; }
+        static const compound_identity *get() { return &T::_identity; }
     };
 
     template<class T>
diff --git a/library/include/MiscUtils.h b/library/include/MiscUtils.h
index 2b9426202d..2ff04282e4 100644
--- a/library/include/MiscUtils.h
+++ b/library/include/MiscUtils.h
@@ -400,7 +400,7 @@ typename T::mapped_type findPrefixInMap(
 #endif
 
 template<class CT>
-inline bool static_add_to_map(CT *pmap, typename CT::key_type key, typename CT::mapped_type value) {
+inline bool static_add_to_map(CT *pmap, const typename CT::key_type key, const typename CT::mapped_type value) {
     (*pmap)[key] = value;
     return true;
 }
diff --git a/library/include/modules/Gui.h b/library/include/modules/Gui.h
index 222779a8ee..63939fc247 100644
--- a/library/include/modules/Gui.h
+++ b/library/include/modules/Gui.h
@@ -211,7 +211,7 @@ namespace DFHack
         /// Get the current top-level view-screen
         DFHACK_EXPORT df::viewscreen *getCurViewscreen(bool skip_dismissed = false);
 
-        DFHACK_EXPORT df::viewscreen *getViewscreenByIdentity(virtual_identity &id, int n = 1);
+        DFHACK_EXPORT df::viewscreen *getViewscreenByIdentity(const virtual_identity &id, int n = 1);
 
         /// Get the top-most underlying DF viewscreen (not owned by DFHack)
         DFHACK_EXPORT df::viewscreen *getDFViewscreen(bool skip_dismissed = false, df::viewscreen *top = NULL);
diff --git a/library/modules/Gui.cpp b/library/modules/Gui.cpp
index dedcc6cdbc..b5df3ca990 100644
--- a/library/modules/Gui.cpp
+++ b/library/modules/Gui.cpp
@@ -152,9 +152,10 @@ static std::string getNameChunk(virtual_identity *id, int start, int end)
  */
 
 typedef void (*getFocusStringsHandler)(std::string &str, std::vector<std::string> &strList, df::viewscreen *screen);
-static std::map<virtual_identity*, getFocusStringsHandler> getFocusStringsHandlers;
+static std::map<const virtual_identity*, getFocusStringsHandler> getFocusStringsHandlers;
 
 #define VIEWSCREEN(name) df::viewscreen_##name##st
+
 #define DEFINE_GET_FOCUS_STRING_HANDLER(screen_type) \
     static void getFocusStrings_##screen_type(const std::string &baseFocus, std::vector<std::string> &focusStrings, VIEWSCREEN(screen_type) *screen);\
     DFHACK_STATIC_ADD_TO_MAP(\
@@ -2718,7 +2719,7 @@ df::viewscreen *Gui::getCurViewscreen(bool skip_dismissed)
     return ws;
 }
 
-df::viewscreen *Gui::getViewscreenByIdentity (virtual_identity &id, int n)
+df::viewscreen *Gui::getViewscreenByIdentity (const virtual_identity &id, int n)
 {
     bool limit = (n > 0);
     df::viewscreen *screen = Gui::getCurViewscreen();