Rework of FFI, adding a value identifier, so we can keep knowledge of data even when data moves.

src/static_data/species_data/form.rs

@@ -4,13 +4,15 @@ use crate::static_data::Statistic;
 use crate::static_data::TypeIdentifier;
 use crate::static_data::{Ability, StaticStatisticSet};
 use crate::static_data::{AbilityIndex, LearnableMoves};
-use crate::Random;
 use crate::StringKey;
+use crate::{Random, ValueIdentifiable, ValueIdentifier};
 
 /// A form is a variant of a specific species. A species always has at least one form, but can have
 /// many more.
 #[derive(Debug)]
 pub struct Form {
+    /// A unique identifier so we know what value this is.
+    identifier: ValueIdentifier,
     /// The name of the form.
     name: StringKey,
     /// The height of the form in meters.
@@ -48,6 +50,7 @@ impl Form {
         flags: HashSet<StringKey>,
     ) -> Form {
         Form {
+            identifier: Default::default(),
             name: name.clone(),
             height,
             weight,
@@ -156,3 +159,9 @@ impl Form {
         self.flags.contains(key)
     }
 }
+
+impl ValueIdentifiable for Form {
+    fn value_identifier(&self) -> ValueIdentifier {
+        self.identifier
+    }
+}