diff --git a/project/components/header_end.hpp b/project/components/header_end.hpp
index d00e31d..238da02 100644
--- a/project/components/header_end.hpp
+++ b/project/components/header_end.hpp
@@ -155,6 +155,11 @@ extern CodeType t_typename;
 
 #pragma endregion Macros
 
+// Used by the lexer to persistently treat all these identifiers as preprocessor defines.
+// Populate with strings via gen::get_cached_string.
+// Functional defines must have format: id( ;at minimum to indicate that the define is only valid with arguments.
+extern Array< StringCached > PreprocessorDefines;
+
 #ifdef GEN_EXPOSE_BACKEND
 
 	// Global allocator used for data with process lifetime.
diff --git a/project/components/interface.cpp b/project/components/interface.cpp
index ae87295..48de1b0 100644
--- a/project/components/interface.cpp
+++ b/project/components/interface.cpp
@@ -289,6 +289,9 @@ void init()
 			GEN_FATAL( "gen::init: Failed to initialize the StringCache");
 	}
 
+	// Preprocessor Defines
+	PreprocessorDefines = Array<StringCached>::init_reserve( GlobalAllocator, kilobytes(1) );
+
 	define_constants();
 	parser::init();
 }
@@ -332,6 +335,8 @@ void deinit()
 	}
 	while ( left--, left );
 
+	PreprocessorDefines.free();
+
 	Global_AllocatorBuckets.free();
 	parser::deinit();
 }
@@ -418,18 +423,18 @@ Code make_code()
 	}
 
 	Code result { rcast( AST*, alloc( * allocator, sizeof(AST) )) };
-	// mem_set( result.ast, 0, sizeof(AST) );
-	result->Type = ECode::Invalid;
+	mem_set( result.ast, 0, sizeof(AST) );
+	// result->Type = ECode::Invalid;
 
-	result->Content     = { nullptr };
-	result->Prev        = { nullptr };
-	result->Next        = { nullptr };
-	result->Token		= nullptr;
-	result->Parent      = { nullptr };
-	result->Name        = { nullptr };
-	result->Type        = ECode::Invalid;
-	result->ModuleFlags = ModuleFlag::Invalid;
-	result->NumEntries  = 0;
+	// result->Content     = { nullptr };
+	// result->Prev        = { nullptr };
+	// result->Next        = { nullptr };
+	// result->Token		= nullptr;
+	// result->Parent      = { nullptr };
+	// result->Name        = { nullptr };
+	// result->Type        = ECode::Invalid;
+	// result->ModuleFlags = ModuleFlag::Invalid;
+	// result->NumEntries  = 0;
 
 	return result;
 }
diff --git a/project/components/lexer.cpp b/project/components/lexer.cpp
index afc0a59..cbe5d87 100644
--- a/project/components/lexer.cpp
+++ b/project/components/lexer.cpp
@@ -12,7 +12,6 @@ enum TokFlags : u32
 	TF_Assign          = bit(1),
 	TF_Preprocess      = bit(2),
 	TF_Preprocess_Cond = bit(3),
-	TF_Comment         = bit(4),
 	TF_Attribute       = bit(6),
 	TF_AccessSpecifier = bit(7),
 	TF_Specifier 	   = bit(8),
@@ -154,7 +153,9 @@ struct TokArray
 	}
 };
 
-global Array<Token> Tokens;
+global Arena_64KB      defines_map_arena;
+global HashTable<StrC> defines;
+global Array<Token>    Tokens;
 
 #define current ( * scanner )
 
@@ -534,6 +535,7 @@ void lex_found_token( StrC& content
 	Tokens.append( token );
 }
 
+
 neverinline
 TokArray lex( StrC content )
 {
@@ -553,8 +555,23 @@ TokArray lex( StrC content )
 		return { { nullptr }, 0 };
 	}
 
-	local_persist Arena_64KB defines_map_arena = Arena_64KB::init();
-	HashTable<StrC> defines = HashTable<StrC>::init( defines_map_arena );
+	for ( StringCached entry : PreprocessorDefines )
+	{
+		s32         length  = 0;
+		char const* scanner = entry.Data;
+		while ( entry.length() > length && char_is_alphanumeric( *scanner ) || *scanner == '_' )
+		{
+			scanner++;
+			length ++;
+		}
+		if ( scanner[1] == '(' )
+		{
+			length++;
+		}
+
+		u64 key = crc32( entry.Data, length );
+		defines.set( key, entry );
+	}
 
 	Tokens.clear();
 
@@ -1036,7 +1053,7 @@ TokArray lex( StrC content )
 					{
 						token.Type   = TokType::Comment;
 						token.Length = 2;
-						token.Flags  = TF_Comment;
+						token.Flags  = TF_Null;
 						move_forward();
 
 						while ( left && current != '\n' && current != '\r' )
@@ -1062,7 +1079,7 @@ TokArray lex( StrC content )
 					{
 						token.Type   = TokType::Comment;
 						token.Length = 2;
-						token.Flags  = TF_Comment;
+						token.Flags  = TF_Null;
 						move_forward();
 
 						bool star   = current    == '*';
diff --git a/project/components/static_data.cpp b/project/components/static_data.cpp
index cf08c6c..b73a03f 100644
--- a/project/components/static_data.cpp
+++ b/project/components/static_data.cpp
@@ -81,6 +81,8 @@ global CodeType t_wchar_t;
 global CodeType t_class;
 global CodeType t_typename;
 
+global Array< StringCached > PreprocessorDefines;
+
 #ifdef GEN_DEFINE_LIBRARY_CODE_CONSTANTS
 global CodeType t_b32;
 
diff --git a/project/components/types.hpp b/project/components/types.hpp
index b9d5437..142f3d3 100644
--- a/project/components/types.hpp
+++ b/project/components/types.hpp
@@ -44,6 +44,7 @@ char const* to_str( AccessSpec type )
 
 enum CodeFlag : u32
 {
+	None          = 0,
 	FunctionType  = bit(0),
 	ParamPack     = bit(1),
 	Module_Export = bit(2),
diff --git a/project/dependencies/containers.hpp b/project/dependencies/containers.hpp
index 391df5e..eab4a5c 100644
--- a/project/dependencies/containers.hpp
+++ b/project/dependencies/containers.hpp
@@ -5,6 +5,14 @@
 
 #pragma region Containers
 
+template<class TType>			struct RemoveConst						{ typedef TType Type; };
+template<class TType>			struct RemoveConst<const TType>			{ typedef TType Type; };
+template<class TType>			struct RemoveConst<const TType[]>		{ typedef TType Type[]; };
+template<class TType, uw Size>	struct RemoveConst<const TType[Size]>	{ typedef TType Type[Size]; };
+
+template<class TType>
+using TRemoveConst = typename RemoveConst<TType>::Type;
+
 template<class Type>
 struct Array
 {
@@ -167,7 +175,8 @@ struct Array
 
 	Header* get_header( void )
 	{
-		return rcast( Header*, Data ) - 1 ;
+		using NonConstType = TRemoveConst< Type >;
+		return rcast( Header*, const_cast<NonConstType*>(Data) ) - 1 ;
 	}
 
 	bool grow( uw min_capacity )