diff --git a/parsercheck.cc b/parsercheck.cc
index 63b7c7b..fd88e39 100644
--- a/parsercheck.cc
+++ b/parsercheck.cc
@@ -42,16 +42,6 @@ T_Array< T_SRDError > parserPrototypes(
 	T_Visitor< opast::A_Node > visitor{ ASTVisitorBrowser };
 	T_Array< T_SRDError > errors;
 
-	enum class E_DataType {
-		UNKNOWN ,
-		ALIAS ,
-		VARIABLE ,
-		FRAMEBUFFER ,
-		INPUT ,
-		PIPELINE ,
-		PROGRAM ,
-		TEXTURE ,
-	};
 	struct T_Decl_ {
 		E_DataType type;
 		T_SRDLocation location;
@@ -60,8 +50,15 @@ T_Array< T_SRDError > parserPrototypes(
 				T_SRDLocation const& loc ) noexcept
 			: type( dt ) , location( loc )
 		{ }
+
+		T_Decl_( const E_DataType dt ) noexcept
+			: type( dt ) , location{}
+		{ }
 	};
 	T_KeyValueTable< T_String , T_Decl_ > type;
+	type.add( T_String::Pooled( "time" ) , T_Decl_{ E_DataType::BUILTIN } );
+	type.add( T_String::Pooled( "width" ) , T_Decl_{ E_DataType::BUILTIN } );
+	type.add( T_String::Pooled( "height" ) , T_Decl_{ E_DataType::BUILTIN } );
 
 	visitor.visit( *root , [&]( A_Node& node , bool exit ) -> bool {
 		if ( exit ) {
@@ -71,79 +68,40 @@ T_Array< T_SRDError > parserPrototypes(
 		E_DataType dt{ E_DataType::UNKNOWN };
 		T_String id;
 		T_SRDLocation location;
-		switch ( node.type( ) ) {
-
-		    case A_Node::OP_FRAMEBUFFER:
-			dt = E_DataType::FRAMEBUFFER;
-			id = dynamic_cast< T_FramebufferInstrNode& >( node ).id( );
-			location = dynamic_cast< T_FramebufferInstrNode& >( node ).idLocation( );
-			break;
-
-		    case A_Node::OP_INPUT:
-			dt = E_DataType::INPUT;
-			id = dynamic_cast< T_InputInstrNode& >( node ).name( );
-			location = dynamic_cast< T_InputInstrNode& >( node ).nameLocation( );
-			break;
-
-		    case A_Node::OP_PIPELINE:
-			dt = E_DataType::PIPELINE;
-			id = dynamic_cast< T_PipelineInstrNode& >( node ).id( );
-			location = dynamic_cast< T_PipelineInstrNode& >( node ).idLocation( );
-			break;
-
-		    case A_Node::OP_PROGRAM:
-			dt = E_DataType::PROGRAM;
-			id = dynamic_cast< T_ProgramInstrNode& >( node ).id( );
-			location = dynamic_cast< T_ProgramInstrNode& >( node ).idLocation( );
-			break;
-
-		    case A_Node::OP_SET:
+		if ( node.type( ) == A_Node::OP_SET ) {
 			dt = E_DataType::VARIABLE;
 			id = dynamic_cast< T_SetInstrNode& >( node ).id( );
 			location = dynamic_cast< T_SetInstrNode& >( node ).idLocation( );
-			break;
-
-		    case A_Node::OP_TEXTURE:
-			dt = E_DataType::TEXTURE;
-			id = dynamic_cast< T_TextureInstrNode& >( node ).id( );
-			location = dynamic_cast< T_TextureInstrNode& >( node ).idLocation( );
-			break;
-
-		    // TODO: samplers
-
-		    default:
-			return !dynamic_cast< A_ExpressionNode* >( &node );
+		} else {
+			auto* np{ dynamic_cast< A_ResourceDefInstrNode* >( &node ) };
+			if ( !np ) {
+				return !dynamic_cast< A_ExpressionNode* >( &node );
+			}
+			dt = np->dataType( );
+			id = np->id( );
+			location = np->idLocation( );
 		}
-
 		assert( dt != E_DataType::UNKNOWN );
+
 		T_Decl_ const* const existing( type.get( id ) );
 		if ( !existing ) {
 			type.add( id , T_Decl_{ dt , location } );
-		} else if ( existing->type != dt ) {
-			T_StringBuilder sb;
-			sb << "'" << id << "' redeclared as ";
-			switch ( dt ) {
-				case E_DataType::VARIABLE: sb << "variable"; break;
-				case E_DataType::FRAMEBUFFER: sb << "framebuffer"; break;
-				case E_DataType::INPUT: sb << "input"; break;
-				case E_DataType::PIPELINE: sb << "pipeline"; break;
-				case E_DataType::PROGRAM: sb << "program"; break;
-				case E_DataType::TEXTURE: sb << "texture"; break;
-				default: std::abort( );
-			}
-			sb << "; previous declaration as ";
-			switch ( existing->type ) {
-				case E_DataType::VARIABLE: sb << "variable"; break;
-				case E_DataType::FRAMEBUFFER: sb << "framebuffer"; break;
-				case E_DataType::INPUT: sb << "input"; break;
-				case E_DataType::PIPELINE: sb << "pipeline"; break;
-				case E_DataType::PROGRAM: sb << "program"; break;
-				case E_DataType::TEXTURE: sb << "texture"; break;
-				default: std::abort( );
-			}
-			sb << " at " << existing->location;
-			errors.addNew( std::move( sb ) , location );
+			return false;
 		}
+		if ( existing->type == dt ) {
+			return false;
+		}
+
+		T_StringBuilder sb;
+		if ( existing->type == E_DataType::BUILTIN ) {
+			sb << "trying to redefine built-in variable " << id;
+		} else {
+			sb << "'" << id << "' redeclared as " << dt
+				<< "; previous declaration as "
+				<< existing->type << " at "
+				<< existing->location;
+		}
+		errors.addNew( std::move( sb ) , location );
 
 		return false;
 	} );