Parser - clear instruction

.vim.local/syntax/demo-srd.vim

@@ -45,7 +45,7 @@ syn keyword srdKWDebug		profiling odbg ui-overrides
 syn keyword srdKWState		use-texture use-framebuffer use-program use-pipeline
 syn keyword srdKWState		uniforms uniforms-i viewport main-output
 
-syn keyword srdKWDraw		fullscreen
+syn keyword srdKWDraw		clear fullscreen
 
 syn keyword srdKWExpr		add sub mul div pow
 syn keyword srdKWExpr		cmp-eq cmp-ne cmp-gt cmp-ge cmp-lt cmp-le

opast.cc

@@ -125,6 +125,16 @@ A_Node* opast::ASTVisitorBrowser(
 		break;
 	    }
 
+	    // Clear instruction
+	    case A_Node::OP_CLEAR:
+	    {
+		auto& n( (T_ClearInstrNode&) node );
+		if ( child < n.components( ) ) {
+			return &n.component( child );
+		}
+		break;
+	    }
+
 	    // Conditional instruction
 	    case A_Node::OP_COND:
 	    {

opast.hh

@@ -21,6 +21,7 @@ class A_Node
 		DECL_FN ,	// Function
 		//
 		OP_CALL ,	// Function call
+		OP_CLEAR ,	// Clear buffer
 		OP_COND ,	// Conditional instruction
 		OP_FRAMEBUFFER ,// Define framebuffer
 		OP_FULLSCREEN ,	// Draw a fullscreen quad
@@ -326,6 +327,27 @@ class T_CallInstrNode : public A_InstructionNode
 		{ return *arguments_[ index ]; }
 };
 
+// Clear instruction
+class T_ClearInstrNode : public A_InstructionNode
+{
+    private:
+	T_StaticArray< P_ExpressionNode , 4 > components_;
+
+    public:
+	T_ClearInstrNode( T_InstrListNode& parent ) noexcept
+		: A_InstructionNode( OP_CLEAR , parent )
+	{ }
+
+	void addComponent( P_ExpressionNode expr ) noexcept
+		{ if ( expr ) { components_.add( std::move( expr ) ); } }
+
+	uint32_t components( ) const noexcept
+		{ return components_.size( ); }
+
+	A_ExpressionNode& component( const uint32_t index ) const noexcept
+		{ return *components_[ index ]; }
+};
+
 // Conditional instruction
 class T_CondInstrNode : public A_InstructionNode
 {
@@ -940,8 +962,7 @@ class T_ViewportInstrNode : public A_InstructionNode
 
     public:
 	T_ViewportInstrNode( T_InstrListNode& parent ) noexcept
-		: A_InstructionNode( OP_VIEWPORT , parent ,
+		: A_InstructionNode( OP_VIEWPORT , parent )
-				E_InstrRestriction::INIT )
 	{ }
 
 	void setParameter( const E_Parameter p , P_ExpressionNode height ) noexcept

opparser.cc

@@ -14,6 +14,7 @@ struct T_ParserImpl_
 {
 	enum class E_InstrType {
 		CALL ,
+		CLEAR ,
 		FRAMEBUFFER ,
 		FULLSCREEN ,
 		IF ,
@@ -43,6 +44,7 @@ struct T_ParserImpl_
 		} };
 
 		add( "call" , E_InstrType::CALL );
+		add( "clear" , E_InstrType::CLEAR );
 		add( "framebuffer" , E_InstrType::FRAMEBUFFER );
 		add( "fullscreen" , E_InstrType::FULLSCREEN );
 		add( "if" , E_InstrType::IF );
@@ -187,6 +189,7 @@ struct T_ParserImpl_
 			T_SRDList const& input ) noexcept
 
 	M_DPARSER_( Call );
+	M_DPARSER_( Clear );
 
 	M_DPARSER_( Framebuffer );
 	bool parseFramebufferEntry(
@@ -488,6 +491,7 @@ void T_ParserImpl_::parseInstructions(
 #define M_CASE_( NAME , FNAME ) case E_InstrType::NAME: parse##FNAME##Instruction( instructions , ilist ); break
 		switch ( *instrMap.get( iword ) ) {
 			M_CASE_( CALL , Call );
+			M_CASE_( CLEAR , Clear );
 			M_CASE_( FRAMEBUFFER , Framebuffer );
 			M_CASE_( IF , If );
 			M_CASE_( INPUT , Input );
@@ -564,6 +568,23 @@ M_INSTR_( Call )
 
 /*----------------------------------------------------------------------------*/
 
+M_INSTR_( Clear )
+{
+	if ( input.size( ) < 5 ) {
+		errors.addNew( "not enough arguments" , input[ 0 ].location( ) );
+	} else if ( input.size( ) > 5 ) {
+		errors.addNew( "too many arguments" , input[ 0 ].location( ) );
+	}
+
+	auto& instr{ instructions.add< T_ClearInstrNode >( ) };
+	instr.location( ) = input[ 0 ].location( );
+	for ( auto i = 1u ; i < std::max( 5u , input.size( ) ) ; i ++ ) {
+		instr.addComponent( parseExpression( instr , input[ i ] ) );
+	}
+}
+
+/*----------------------------------------------------------------------------*/
+
 M_INSTR_( Framebuffer )
 {
 	if ( input.size( ) == 1 || input[ 1 ].type( ) != E_SRDTokenType::WORD ) {