class EnumValueSymbols lets you specify a table...

... of EnumValueSymbol either row-wise or column-wise

src/Prefs.cpp

@@ -239,6 +239,42 @@ void FinishPreferences()
    }
 }
 
+//////////
+EnumValueSymbols::EnumValueSymbols(
+   ByColumns_t,
+   const wxArrayStringEx &msgids,
+   wxArrayStringEx internals
+)
+   : mInternals( std::move( internals ) )
+{
+   auto size = mInternals.size(), size2 = msgids.size();
+   if ( size != size2 ) {
+      wxASSERT( false );
+      size = std::min( size, size2 );
+   }
+   reserve( size );
+   auto iter1 = mInternals.begin();
+   auto iter2 = msgids.begin();
+   while( size-- )
+      emplace_back( *iter1++, *iter2++ );
+}
+
+const wxArrayStringEx &EnumValueSymbols::GetTranslations() const
+{
+   if ( mTranslations.empty() )
+      mTranslations = transform_container<wxArrayStringEx>( *this,
+         std::mem_fn( &EnumValueSymbol::Translation ) );
+   return mTranslations;
+}
+
+const wxArrayStringEx &EnumValueSymbols::GetInternals() const
+{
+   if ( mInternals.empty() )
+      mInternals = transform_container<wxArrayStringEx>( *this,
+         std::mem_fn( &EnumValueSymbol::Internal ) );
+   return mInternals;
+}
+
 //////////
 wxString ChoiceSetting::Read() const
 {
@@ -260,9 +296,9 @@ wxString ChoiceSetting::Read() const
 
 size_t ChoiceSetting::Find( const wxString &value ) const
 {
-   auto start = begin();
+   auto start = GetSymbols().begin();
    return size_t(
-      std::find( start, end(), EnumValueSymbol{ value, {} } )
+      std::find( start, GetSymbols().end(), EnumValueSymbol{ value, {} } )
          - start );
 }
 
@@ -346,3 +382,5 @@ wxString WarningDialogKey(const wxString &internalDialogName)
 {
    return wxT("/Warnings/") + internalDialogName;
 }
+
+ByColumns_t ByColumns{};

src/Prefs.h

@@ -32,6 +32,7 @@
 #include "Audacity.h"
 
 #include "../include/audacity/ComponentInterface.h"
+#include "MemoryX.h" // for wxArrayStringEx
 
 #include <memory>
 #include <wx/fileconf.h>  // to inherit wxFileConfig
@@ -86,7 +87,37 @@ public:
    int mVersionMicroKeyInit{};
 };
 
-using EnumValueSymbols = std::vector< EnumValueSymbol >;
+struct ByColumns_t{};
+extern ByColumns_t ByColumns;
+
+/// A table of EnumValueSymbol that you can access by "row" with
+/// operator [] but also allowing access to the "columns" of internal or
+/// translated strings, and also allowing convenient column-wise construction
+class EnumValueSymbols : public std::vector< EnumValueSymbol >
+{
+public:
+   EnumValueSymbols() = default;
+   EnumValueSymbols( std::initializer_list<EnumValueSymbol> symbols )
+     : vector( symbols )
+   {}
+
+   // columnwise constructor; arguments must have same size
+   // (Implicit constructor takes initial tag argument to avoid unintended
+   // overload resolution to the inherited constructor taking
+   // initializer_list, in the case that each column has exactly two strings)
+   EnumValueSymbols(
+      ByColumns_t,
+      const wxArrayStringEx &msgids, // untranslated!
+      wxArrayStringEx internals
+   );
+
+   const wxArrayStringEx &GetTranslations() const;
+   const wxArrayStringEx &GetInternals() const;
+
+private:
+   mutable wxArrayStringEx mTranslations;
+   mutable wxArrayStringEx mInternals;
+};
 
 /// Packages a table of user-visible choices each with an internal code string,
 /// a preference key path, and a default choice
@@ -110,8 +141,7 @@ public:
    const wxString &Key() const { return mKey; }
    const EnumValueSymbol &Default() const
       { return mSymbols[mDefaultSymbol]; }
-   EnumValueSymbols::const_iterator begin() const { return mSymbols.begin(); }
-   EnumValueSymbols::const_iterator end() const { return mSymbols.end(); }
+   const EnumValueSymbols &GetSymbols() const { return mSymbols; }
 
    wxString Read() const;
    bool Write( const wxString &value ); // you flush gPrefs afterward

src/ShuttleGui.cpp

@@ -1866,14 +1866,15 @@ wxChoice *ShuttleGuiBase::TieChoice(
    // Do this to force any needed migrations first
    choiceSetting.Read();
 
-   wxArrayStringEx visibleChoices, internalChoices;
-   for (const auto &ident : choiceSetting) {
-      visibleChoices.push_back( ident.Translation() );
-      internalChoices.push_back( ident.Internal() );
-   }
+   const auto &symbols = choiceSetting.GetSymbols();
+
    return TieChoice(
-      Prompt, choiceSetting.Key(), choiceSetting.Default().Internal(),
-         visibleChoices, internalChoices );
+      Prompt,
+      choiceSetting.Key(),
+      choiceSetting.Default().Internal(),
+      symbols.GetTranslations(),
+      symbols.GetInternals()
+   );
 }
 
 /// Variant of the standard TieChoice which does the two step exchange