ZoneCodeGenerator: Make unions work with conditions and only load one union member at a time consistently

src/ZoneCodeGenerator/Generating/Computations/MemberComputations.cs

@@ -73,6 +73,12 @@ namespace ZoneCodeGenerator.Generating.Computations
         public bool IsNotDefaultNormalBlock =>
             information.Block != null && !(information.Block.IsNormal && information.Block.IsDefault);
 
+        public bool IsFirstMember =>
+            information.Parent.OrderedMembers.FirstOrDefault(member => !member.IsLeaf && !member.Computations.ShouldIgnore) == information;
+
+        public bool IsLastMember =>
+            information.Parent.OrderedMembers.LastOrDefault(member => !member.IsLeaf && !member.Computations.ShouldIgnore) == information;
+
         public MemberReferenceComputations References => new MemberReferenceComputations(information);
 
         public MemberComputations(MemberInformation information)

src/ZoneCodeGenerator/Generating/Templates/ZoneLoad.stg

@@ -79,35 +79,86 @@ Loading member $member.Member.Name$
 
 LoadMemberReference(context, structure, member, reference) ::= <%
 $if(reference.IsSinglePointer)$
-$\n$$\n$
 $LoadSinglePointer(context, structure, member, reference)$
 $elseif(reference.IsArrayPointer)$
-$\n$$\n$
 $LoadArrayPointer(context, structure, member, reference)$
 $elseif(reference.IsPointerArray)$
-$\n$$\n$
 $LoadPointerArray(context, structure, member, reference)$
 $elseif(reference.IsArray && !reference.NextReference)$
-$\n$$\n$
 $LoadEmbeddedArray(context, structure, member, reference)$
 $elseif(!reference.Reference)$
-$\n$$\n$
 $LoadEmbedded(context, structure, member, reference)$
 $else$
-$\n$$\n$
 // $member.Member.Name$
 $endif$
 %>
 
+LoadMemberCondition_Struct(context, structure, member) ::= <<
+
+
+$if(member.Condition)$
+if($PrintEvaluation(member.Condition)$)
+{
+    $LoadMemberReference(context, structure, member, member.Computations.References)$
+}$\\$
+$else$
+$LoadMemberReference(context, structure, member, member.Computations.References)$$\\$
+$endif$
+>>
+
+LoadMemberCondition_Union(context, structure, member) ::= <<
+$if(member.Computations.IsFirstMember)$$\\$
+$if(member.Condition)$
+
+if($PrintEvaluation(member.Condition)$)
+{
+    $LoadMemberReference(context, structure, member, member.Computations.References)$
+}$\\$
+$else$
+
+$LoadMemberReference(context, structure, member, member.Computations.References)$$\\$
+$endif$$\\$
+$elseif(member.Computations.IsLastMember)$$\\$
+$if(member.Condition)$
+else if($PrintEvaluation(member.Condition)$)
+{
+    $LoadMemberReference(context, structure, member, member.Computations.References)$
+}$\\$
+$else$
+else
+{
+    $LoadMemberReference(context, structure, member, member.Computations.References)$
+}$\\$
+$endif$$\\$
+$else$$\\$
+$if(member.Condition)$
+else if($PrintEvaluation(member.Condition)$)
+{
+    $LoadMemberReference(context, structure, member, member.Computations.References)$
+}$\\$
+$else$$\\$
+#error Middle member of union must have condition ($member.Member.Name$)
+$endif$$\\$
+$endif$
+>>
+
+LoadMemberCondition(context, structure, member) ::= <%
+$if(structure.IsUnion)$
+$LoadMemberCondition_Union(context, structure, member)$
+$else$
+$LoadMemberCondition_Struct(context, structure, member)$
+$endif$
+%>
+
 LoadMemberIfNeedsTreatment(context, structure, member) ::= <%
 $if(!member.Computations.ShouldIgnore)$
 
 $if(member.IsString || member.IsScriptString)$
-$LoadMemberReference(context, structure, member, member.Computations.References)$
+$LoadMemberCondition(context, structure, member)$
 $elseif(member.Computations.ContainsNonEmbeddedReference)$
-$LoadMemberReference(context, structure, member, member.Computations.References)$
+$LoadMemberCondition(context, structure, member)$
 $elseif(member.StructureType && !member.StructureType.IsLeaf)$
-$LoadMemberReference(context, structure, member, member.Computations.References)$
+$LoadMemberCondition(context, structure, member)$
 $endif$
 
 $endif$