repaired broken let, letast, letrec handling
This commit is contained in:
		| @ -341,13 +341,17 @@ Ada.Text_IO.Put_Line ("NO ALTERNATE"); | ||||
| 			Push_Top (Interp, Envir'Unchecked_Access); | ||||
| 			Envir := Get_Frame_Environment(Get_Frame_Parent(Interp.Stack)); | ||||
|  | ||||
| 			-- Create an array to hold the binding list and the evaluation result | ||||
| 			Cdr := Make_Array (Interp.Self, 3); | ||||
| 			Cdr.Pointer_Slot(1) := Car; | ||||
|  | ||||
| 			-- The actual binding after evaluation must be performed in the  | ||||
| 			-- new environment. | ||||
| 			Push_Frame (Interp, Opcode_Let_Binding, Car); | ||||
| 			Push_Frame (Interp, Opcode_Let_Binding, Cdr); | ||||
|  | ||||
| 			-- But evaluation must be done in the current environment which is  | ||||
| 			-- the environment before the environment update above. | ||||
| 			Push_Frame_With_Environment (Interp, Opcode_Let_Evaluation, Car, Envir);  | ||||
| 			Push_Frame_With_Environment (Interp, Opcode_Let_Evaluation, Cdr, Envir);  | ||||
| 			Pop_Tops (Interp, 1); | ||||
| 		end if; | ||||
| 	end Evaluate_Let_Syntax; | ||||
| @ -393,8 +397,11 @@ Ada.Text_IO.Put_Line ("NO ALTERNATE"); | ||||
| 			-- <bindings> is not empty | ||||
| 			-- Arrange to perform evaluataion and binding in the | ||||
| 			-- new environment created. | ||||
| 			Push_Frame (Interp, Opcode_Let_Binding, Car); | ||||
| 			Push_Frame (Interp, Opcode_Let_Evaluation, Car);  | ||||
| 			Cdr := Make_Array (Interp.Self, 3); | ||||
| 			Cdr.Pointer_Slot(1) := Car; | ||||
|  | ||||
| 			Push_Frame (Interp, Opcode_Let_Binding, Cdr); | ||||
| 			Push_Frame (Interp, Opcode_Let_Evaluation, Cdr);  | ||||
| 		end if; | ||||
| 	end Evaluate_Letrec_Syntax; | ||||
|  | ||||
|  | ||||
| @ -145,15 +145,15 @@ procedure Execute (Interp: in out Interpreter_Record) is | ||||
| 		R := Make_Cons(Interp.Self, Get_Car(Get_Frame_Result(Interp.Stack)), R);  | ||||
|  | ||||
| 		Clear_Frame_Result (Interp.Stack); | ||||
| 		if not Is_Cons(S) then | ||||
| 		if Is_Cons(S) then | ||||
| 			Set_Cdr (X, R); -- chain the result | ||||
| 			Set_Car (X, Get_Cdr(S)); -- remember the next <operator> to evaluate | ||||
| 			Push_Frame (Interp, Opcode_Evaluate_Object, Get_Car(S)); | ||||
| 		else | ||||
| 			-- no more argument to evaluate.  | ||||
| 			-- apply the evaluated arguments to the evaluated operator. | ||||
| 			Set_Frame_Opcode (Interp.Stack, Opcode_Apply);  | ||||
| 			Set_Frame_Operand (Interp.Stack, Reverse_Cons(R)); | ||||
| 		else | ||||
| 			Set_Cdr (X, R); | ||||
| 			Set_Car (X, Get_Cdr(S));  | ||||
| 			Push_Frame (Interp, Opcode_Evaluate_Object, Get_Car(S)); | ||||
| 		end if; | ||||
|  | ||||
| 		Pop_Tops (Interp, 3); | ||||
| @ -216,56 +216,108 @@ pragma Assert (Get_Cdr(R) = Nil_Pointer); | ||||
|  | ||||
| 	procedure Do_Let_Evaluation is | ||||
| 		pragma Inline (Do_Let_Evaluation); | ||||
| 		X: Object_Pointer; | ||||
| 		Y: Object_Pointer; | ||||
| 		X: aliased Object_Pointer; | ||||
| 		S: aliased Object_Pointer; | ||||
| 		R: aliased Object_Pointer; | ||||
| 	begin	 | ||||
| 		X := Get_Frame_Operand(Interp.Stack); -- <bindings> and onward | ||||
| 		Push_Top (Interp, X'Unchecked_Access); | ||||
| 		Push_Top (Interp, S'Unchecked_Access); | ||||
| 		Push_Top (Interp, R'Unchecked_Access); | ||||
|  | ||||
| 		if Is_Cons(X) then | ||||
| 			Set_Frame_Operand (Interp.Stack, Get_Cdr(X)); | ||||
| 			-- Say, <bindings> is ((x 2) (y 2)). | ||||
| 			-- for the first call, Get_Car(X) is (x 2). | ||||
| 			-- To get x, Get_Car(Get_Car(X)) | ||||
| 			-- To get 2, Get_Car(Get_Cdr(Get_Car(X))) | ||||
| 			Push_Frame (Interp, Opcode_Evaluate_Object, Get_Car(Get_Cdr(Get_Car(X)))); | ||||
| 		X := Get_Frame_Operand(Interp.Stack);  | ||||
| 		pragma Assert (Is_Array(X)); | ||||
|  | ||||
| 		R := X.Pointer_Slot(3); | ||||
| 		if R = Nil_Pointer then | ||||
| 			-- First call; | ||||
| 			X.Pointer_Slot(2) := X.Pointer_Slot(1); | ||||
| 		else | ||||
| 			-- Pass the result to the Perform_Let_Binding frame. | ||||
| 			Y := Get_Frame_Result(Interp.Stack); | ||||
| 			Pop_Frame (Interp); | ||||
| 			Set_Frame_Result (Interp.Stack, Y); | ||||
| 			-- Subsequent calls. Store the result in the room created  | ||||
| 			-- in the previous call. | ||||
| 			pragma Assert (Is_Cons(R)); | ||||
| 			Set_Car (R, Get_Car(Get_Frame_Result(Interp.Stack))); | ||||
| 		end if; | ||||
| 	end Do_Let_Evaluation; | ||||
| 		S := X.Pointer_Slot(2); | ||||
|  | ||||
| 		if Is_Cons(S) then | ||||
| 			-- Handle each binding. | ||||
|  | ||||
| 			-- Make an empty room to hold the result on the next call | ||||
| 			R := Make_Cons (Interp.Self, Nil_Pointer, R); | ||||
| 			X.Pointer_Slot(3) := R; | ||||
|  | ||||
| 			-- Remember the next <operator> to evaluate | ||||
| 			X.Pointer_Slot(2) := Get_Cdr(S); | ||||
|  | ||||
| 			-- Say, <bindings> is ((x 2) (y 2)). | ||||
| 			-- for the first call, Get_Car(S) is (x 2). | ||||
| 			-- To get x, Get_Car(Get_Car(S)) | ||||
| 			-- To get 2, Get_Car(Get_Cdr(Get_Car(S))) | ||||
| 			Push_Frame (Interp, Opcode_Evaluate_Object, Get_Car(Get_Cdr(Get_Car(S)))); | ||||
|  | ||||
| 		else | ||||
| 			-- No more binding to handle. | ||||
| 			Pop_Frame (Interp); | ||||
|  | ||||
| 			-- The operands at the Let_Evaluation and the Let_Binding frame | ||||
| 			-- must be the identical objects. this way, i don't need to carry | ||||
| 			-- over the binding result to the Let_Binding frame. | ||||
| 			pragma Assert (X = Get_Frame_Operand(Interp.Stack)); | ||||
| 			pragma Assert (Get_Frame_Opcode(Interp.Stack) = Opcode_Let_Binding); | ||||
| 			--X := Get_Frame_Operand(Interp.Stack); | ||||
| 			--pragma Assert (Is_Array(X)); | ||||
| 			--pragma Assert (X.Pointer_Slot(3) = Nil_Pointer); | ||||
| 			--X.Pointer_Slot(3) := R; | ||||
| 		end if; | ||||
|  | ||||
| 		Pop_Tops (Interp, 3); | ||||
| 	end Do_Let_Evaluation; | ||||
|  | ||||
| 	procedure Do_Let_Binding is | ||||
| 		pragma Inline (Do_Let_Binding); | ||||
| 		X: aliased Object_Pointer; | ||||
| 		Y: aliased Object_Pointer; | ||||
| 		S: aliased Object_Pointer; | ||||
| 		R: aliased Object_Pointer; | ||||
| 	begin | ||||
| 		Push_Top (Interp, X'Unchecked_Access); | ||||
| 		Push_Top (Interp, Y'Unchecked_Access); | ||||
| 		Push_Top (Interp, S'Unchecked_Access); | ||||
| 		Push_Top (Interp, R'Unchecked_Access); | ||||
|  | ||||
| 		-- Evaluation of <bindings> is completed. | ||||
| 		-- Update the environments. | ||||
| 		X := Get_Frame_Operand(Interp.Stack); -- <bindings> and onward | ||||
| 		Y := Reverse_Cons(Get_Frame_Result(Interp.Stack)); | ||||
| 		pragma Assert (Is_Array(X)); | ||||
|  | ||||
| 		while Is_Cons(X) loop | ||||
| 			pragma Assert (Is_Cons(Y)); | ||||
| 			Put_Environment (Interp, Get_Car(Get_Car(X)), Get_Car(Y)); | ||||
| 		S := X.Pointer_Slot(1); | ||||
| 		R := X.Pointer_Slot(3); | ||||
| 		R := Reverse_Cons(R); | ||||
|  | ||||
| 			X := Get_Cdr(X); | ||||
| 			Y := Get_Cdr(Y); | ||||
| 		while Is_Cons(S) loop | ||||
| 			pragma Assert (Is_Cons(R)); | ||||
| 			Put_Environment (Interp, Get_Car(Get_Car(S)), Get_Car(R)); | ||||
| 			S := Get_Cdr(S); | ||||
| 			R := Get_Cdr(R); | ||||
| 		end loop; | ||||
|  | ||||
| 		Pop_Frame (Interp); -- done.  | ||||
| 		pragma Assert (Get_Frame_Opcode(Interp.Stack) = Opcode_Let_Finish); | ||||
|  | ||||
| 		Pop_Tops (Interp, 2); | ||||
| 		Pop_Tops (Interp, 3); | ||||
| 	end Do_Let_Binding; | ||||
|  | ||||
| 	procedure Do_Letast_Binding is | ||||
| 		pragma Inline (Do_Letast_Binding); | ||||
| 		X: Object_Pointer; | ||||
| 	begin | ||||
| 		X := Get_Frame_Operand(Interp.Stack); -- <bindings> and onward | ||||
|  | ||||
| 		-- Don't call this procedure if <bindings> is empty. The caller must ensure this | ||||
| 		pragma Assert (Is_Cons(X));  | ||||
|  | ||||
| 		Set_Frame_Opcode (Interp.Stack, Opcode_Letast_Binding_Finish); | ||||
| 		Push_Frame (Interp, Opcode_Evaluate_Object, Get_Car(Get_Cdr(Get_Car(X)))); | ||||
| 	end Do_Letast_Binding; | ||||
|  | ||||
| 	procedure Do_Letast_Binding_Finish is | ||||
| 		pragma Inline (Do_Letast_Binding_Finish); | ||||
| 		X: aliased Object_Pointer; | ||||
| 		Y: aliased Object_Pointer; | ||||
| 		Envir: aliased Object_Pointer; | ||||
| @ -277,40 +329,33 @@ pragma Assert (Get_Cdr(R) = Nil_Pointer); | ||||
| 		X := Get_Frame_Operand(Interp.Stack); -- <bindings> and onward | ||||
| 		Y := Get_Frame_Result(Interp.Stack); | ||||
|  | ||||
| 		if Y = Nil_Pointer then | ||||
| 			-- First call | ||||
| 			pragma Assert (Is_Cons(X)); -- Don't provoke this procedure if <bindings> is empty. | ||||
| 			Envir := Get_Frame_Environment(Get_Frame_Parent(Interp.Stack));	 | ||||
| 		-- Update the environment while evaluating <bindings> | ||||
|  | ||||
| 		-- Push a new environment for each binding. | ||||
| 		Envir := Make_Environment(Interp.Self, Get_Frame_Environment(Interp.Stack)); | ||||
| 		Set_Frame_Environment (Interp.Stack, Envir); | ||||
| 		Put_Environment (Interp, Get_Car(Get_Car(X)), Get_Car(Y)); | ||||
|  | ||||
| 		X := Get_Cdr(X); -- next binding | ||||
| 		if Is_Cons(X) then | ||||
| 			-- More bingings to evaluate | ||||
| 			Set_Frame_Operand (Interp.Stack, X); | ||||
| 			Clear_Frame_Result (Interp.Stack); | ||||
|  | ||||
| 			-- the next evaluation must be done in the environment where the  | ||||
| 			-- current binding has been made. | ||||
| 			Push_Frame (Interp, Opcode_Evaluate_Object, Get_Car(Get_Cdr(Get_Car(X)))); | ||||
| 		else | ||||
| 			-- Subsequence calls. Update the environment while evaluating <bindings> | ||||
| 			-- No more bingings left | ||||
| 			Pop_Frame (Interp); -- Done | ||||
|  | ||||
| 			-- Push a new environment for each binding. | ||||
| 			Envir := Make_Environment(Interp.Self, Get_Frame_Environment(Interp.Stack)); | ||||
| 			-- Update the environment of the Let_Finish frame. | ||||
| 			pragma Assert (Get_Frame_Opcode(Interp.Stack) = Opcode_Let_Finish); | ||||
| 			Set_Frame_Environment (Interp.Stack, Envir); | ||||
| 			Put_Environment (Interp, Get_Car(Get_Car(X)), Get_Car(Y)); | ||||
|  | ||||
| 			X := Get_Cdr(X); -- next binding | ||||
| 			if Is_Cons(X) then | ||||
| 				-- More bingings to evaluate | ||||
| 				Set_Frame_Operand (Interp.Stack, X); | ||||
| 				Clear_Frame_Result (Interp.Stack); | ||||
|  | ||||
| 				-- the next evaluation must be done in the environment where the  | ||||
| 				-- current binding has been made. | ||||
| 				Push_Frame (Interp, Opcode_Evaluate_Object, Get_Car(Get_Cdr(Get_Car(X)))); | ||||
| 			else | ||||
| 				-- No more bingings left | ||||
| 				Pop_Frame (Interp); -- Done | ||||
|  | ||||
| 				-- Update the environment of the Let_Finish frame. | ||||
| 				pragma Assert (Get_Frame_Opcode(Interp.Stack) = Opcode_Let_Finish); | ||||
| 				Set_Frame_Environment (Interp.Stack, Envir); | ||||
| 			end if; | ||||
| 		end if; | ||||
|  | ||||
| 		Pop_Tops (Interp, 3); | ||||
| 	end Do_Letast_Binding; | ||||
| 	end Do_Letast_Binding_Finish; | ||||
|  | ||||
| 	procedure Do_Let_Finish is | ||||
| 		pragma Inline (Do_Let_Finish); | ||||
| @ -994,6 +1039,8 @@ begin | ||||
| 				Do_Let_Binding;  | ||||
| 			when Opcode_Letast_Binding => | ||||
| 				Do_Letast_Binding;  | ||||
| 			when Opcode_Letast_Binding_Finish => | ||||
| 				Do_Letast_Binding_Finish;  | ||||
| 			when Opcode_Let_Evaluation => | ||||
| 				Do_Let_Evaluation; | ||||
| 			when Opcode_Let_Finish => | ||||
|  | ||||
| @ -93,7 +93,7 @@ package body H2.Scheme is | ||||
|  | ||||
| 	subtype Moved_Object_Record is Object_Record (Moved_Object, 0); | ||||
|  | ||||
| 	subtype Opcode_Type is Object_Integer range 0 .. 21; | ||||
| 	subtype Opcode_Type is Object_Integer range 0 .. 22; | ||||
| 	Opcode_Exit:                 constant Opcode_Type := Opcode_Type'(0); | ||||
| 	Opcode_Evaluate_Result:      constant Opcode_Type := Opcode_Type'(1); | ||||
| 	Opcode_Evaluate_Object:      constant Opcode_Type := Opcode_Type'(2); | ||||
| @ -106,18 +106,19 @@ package body H2.Scheme is | ||||
| 	Opcode_Grouped_Call_Finish:  constant Opcode_Type := Opcode_Type'(8); | ||||
| 	Opcode_Let_Binding:          constant Opcode_Type := Opcode_Type'(9); | ||||
| 	Opcode_Letast_Binding:       constant Opcode_Type := Opcode_Type'(10); | ||||
| 	Opcode_Let_Evaluation:       constant Opcode_Type := Opcode_Type'(11); | ||||
| 	Opcode_Let_Finish:           constant Opcode_Type := Opcode_Type'(12); | ||||
| 	Opcode_Procedure_Call:       constant Opcode_Type := Opcode_Type'(13);  | ||||
| 	Opcode_Set_Finish:           constant Opcode_Type := Opcode_Type'(14);  | ||||
| 	Opcode_Letast_Binding_Finish:constant Opcode_Type := Opcode_Type'(11); | ||||
| 	Opcode_Let_Evaluation:       constant Opcode_Type := Opcode_Type'(12); | ||||
| 	Opcode_Let_Finish:           constant Opcode_Type := Opcode_Type'(13); | ||||
| 	Opcode_Procedure_Call:       constant Opcode_Type := Opcode_Type'(14);  | ||||
| 	Opcode_Set_Finish:           constant Opcode_Type := Opcode_Type'(15);  | ||||
|  | ||||
| 	Opcode_Apply:                constant Opcode_Type := Opcode_Type'(15); | ||||
| 	Opcode_Read_Object:          constant Opcode_Type := Opcode_Type'(16); | ||||
| 	Opcode_Read_List:            constant Opcode_Type := Opcode_Type'(17); | ||||
| 	Opcode_Read_List_Cdr:        constant Opcode_Type := Opcode_Type'(18); | ||||
| 	Opcode_Read_List_End:        constant Opcode_Type := Opcode_Type'(19); | ||||
| 	Opcode_Close_List:           constant Opcode_Type := Opcode_Type'(20); | ||||
| 	Opcode_Close_Quote:          constant Opcode_Type := Opcode_Type'(21); | ||||
| 	Opcode_Apply:                constant Opcode_Type := Opcode_Type'(16); | ||||
| 	Opcode_Read_Object:          constant Opcode_Type := Opcode_Type'(17); | ||||
| 	Opcode_Read_List:            constant Opcode_Type := Opcode_Type'(18); | ||||
| 	Opcode_Read_List_Cdr:        constant Opcode_Type := Opcode_Type'(19); | ||||
| 	Opcode_Read_List_End:        constant Opcode_Type := Opcode_Type'(20); | ||||
| 	Opcode_Close_List:           constant Opcode_Type := Opcode_Type'(21); | ||||
| 	Opcode_Close_Quote:          constant Opcode_Type := Opcode_Type'(22); | ||||
|  | ||||
| 	----------------------------------------------------------------------------- | ||||
| 	-- COMMON OBJECTS | ||||
|  | ||||
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