implemented let*
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@ -220,8 +220,8 @@ Ada.Text_IO.Put_Line ("NO ALTERNATE");
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end;
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end Evaluate_Lambda_Syntax;
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procedure Evaluate_Let_Syntax is
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pragma Inline (Evaluate_Let_Syntax);
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procedure Check_Let_Syntax is
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pragma Inline (Check_Let_Syntax);
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Bindings: Object_Pointer;
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LetBody: Object_Pointer;
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@ -236,7 +236,7 @@ Ada.Text_IO.Put_Line ("NO ALTERNATE");
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end if;
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Bindings := Get_Car(Operand); -- <bindings>
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if not Is_Cons(Bindings) then
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if Bindings /= Nil_Pointer and then not Is_Cons(Bindings) then
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Ada.Text_IO.Put_Line ("INVALID BINDINGS FOR LET");
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raise Syntax_Error;
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end if;
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@ -249,70 +249,103 @@ Ada.Text_IO.Put_Line ("NO ALTERNATE");
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raise Syntax_Error;
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end if;
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Cdr := Bindings;
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loop
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Car := Get_Car(Cdr); -- <binding>
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if not Is_Cons(Car) or else not Is_Cons(Get_Cdr(Car)) or else Get_Cdr(Get_Cdr(Car)) /= Nil_Pointer then
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-- no binding name or no binding value or garbage after that
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Ada.Text_IO.Put_Line ("WRONG BINDING FOR LET");
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raise Syntax_Error;
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end if;
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if not Is_Symbol(Get_Car(Car)) then
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Ada.Text_IO.Put_Line ("WRONG BINDING NAME FOR LET");
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raise Syntax_Error;
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end if;
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-- Check for a duplicate binding name
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if Is_Cons(Bindings) then
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Cdr := Bindings;
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loop
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Car := Get_Car(Cdr); -- <binding>
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if not Is_Cons(Car) or else not Is_Cons(Get_Cdr(Car)) or else Get_Cdr(Get_Cdr(Car)) /= Nil_Pointer then
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-- no binding name or no binding value or garbage after that
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Ada.Text_IO.Put_Line ("WRONG BINDING FOR LET");
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raise Syntax_Error;
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end if;
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if not Is_Symbol(Get_Car(Car)) then
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Ada.Text_IO.Put_Line ("WRONG BINDING NAME FOR LET");
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raise Syntax_Error;
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end if;
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-- Check for a duplicate binding name
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-- TODO: make duplication check optional or change the implementation more efficient so that this check is not repeated
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declare
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V: Object_Pointer;
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begin
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V := Bindings;
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loop
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exit when V = Cdr;
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if Get_Car(Get_Car(V)) = Get_Car(Car) then
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Ada.Text_IO.Put_Line ("DUPLICATE BINDING FOR LET");
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raise Syntax_Error;
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end if;
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V := Get_Cdr(V);
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end loop;
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end;
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declare
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V: Object_Pointer;
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begin
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V := Bindings;
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loop
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exit when V = Cdr;
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if Get_Car(Get_Car(V)) = Get_Car(Car) then
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Ada.Text_IO.Put_Line ("DUPLICATE BINDING FOR LET");
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raise Syntax_Error;
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end if;
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V := Get_Cdr(V);
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end loop;
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end;
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-- Move on to the next binding
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Cdr := Get_Cdr(Cdr);
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exit when not Is_Cons(Cdr);
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end loop;
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if Cdr /= Nil_Pointer then
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-- The last cdr is not nil.
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Ada.Text_IO.Put_Line ("FUCKING CDR FOR LET BINDING");
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raise Syntax_Error;
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end if;
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Cdr := Get_Cdr(Cdr);
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exit when not Is_Cons(Cdr);
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end loop;
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if Cdr /= Nil_Pointer then
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-- The last cdr is not nil.
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Ada.Text_IO.Put_Line ("FUCKING CDR FOR LET BINDING");
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raise Syntax_Error;
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end if;
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end if;
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-- To avoid problems of temporary object pointer problems.
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Car := Bindings;
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Cdr := LetBody;
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end Check_Let_Syntax;
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procedure Evaluate_Let_Syntax is
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pragma Inline (Evaluate_Let_Syntax);
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begin
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Check_Let_Syntax;
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-- Car: <bindings>, Cdr: <body>
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Set_Frame_Opcode (Interp.Stack, Opcode_Let_Finish);
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Set_Frame_Operand (Interp.Stack, Cdr);
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Push_Frame (Interp, Opcode_Let_Binding, Car);
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Push_Frame (Interp, Opcode_Let_Evaluation, Car);
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Interp.Environment := Make_Environment(Interp.Self, Interp.Environment);
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Set_Frame_Environment (Interp.Stack, Interp.Environment);
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-- Some let samples:
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-- #1.
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-- (define x 99)
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-- (let () (define x 100)) ; no actual bindings
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-- x ; this must be 99
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--
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-- #2.
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-- ...
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if Car /= Nil_Pointer then
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-- <bindings> is not empty
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Push_Frame (Interp, Opcode_Let_Binding, Car);
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Push_Frame (Interp, Opcode_Let_Evaluation, Car);
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end if;
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end Evaluate_Let_Syntax;
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procedure Evaluate_Letast_Syntax is
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pragma Inline (Evaluate_Letast_Syntax);
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begin
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Check_Let_Syntax;
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-- Car: <bindings>, Cdr: <body>
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--Set_Frame_Opcode (Interp.Stack, Opcode_Let_Finish);
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--Set_Frame_Operand (Interp.Stack, Cdr);
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-- Letast_Binding must see this new environment
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-- and must make the binding in this environment.
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Interp.Environment := Make_Environment(Interp.Self, Interp.Environment);
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--Push_Frame (Interp, Opcode_Let_Binding, Car);
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--Push_Frame (Interp, Opcode_Let_Evaluation, Car);
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null;
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-- Body evaluation can be done the same way as normal let.
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Set_Frame_Opcode (Interp.Stack, Opcode_Let_Finish);
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Set_Frame_Operand (Interp.Stack, Cdr);
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-- but in the environment pushed above.
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Set_Frame_Environment (Interp.Stack, Interp.Environment);
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if Car /= Nil_Pointer then
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-- <bindings> is not empty
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Push_Frame (Interp, Opcode_Letast_Binding, Car);
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end if;
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end Evaluate_Letast_Syntax;
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procedure Evaluate_Quote_Syntax is
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@ -212,19 +212,11 @@ procedure Execute (Interp: in out Interpreter_Record) is
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Push_Top (Interp, X'Unchecked_Access);
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Push_Top (Interp, Y'Unchecked_Access);
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-- Evaluation of <bindings> is completed.
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-- Update the environments.
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X := Get_Frame_Operand(Interp.Stack); -- <bindings> and onward
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Y := Reverse_Cons(Get_Frame_Result(Interp.Stack));
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pragma Assert (Interp.Environment = Get_Frame_Environment(Interp.Stack));
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-- Push a new environment
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Interp.Environment := Make_Environment(Interp.Self, Interp.Environment);
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-- Change the frame's environment so that Pop_Frame() doesn't
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-- restore the environment to the old one. The new environment
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-- has been just pushed above after binding evaluation.
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Set_Frame_Environment (Interp.Stack, Interp.Environment);
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while Is_Cons(X) loop
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pragma Assert (Is_Cons(Y));
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Put_Environment (Interp, Get_Car(Get_Car(X)), Get_Car(Y));
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@ -234,10 +226,44 @@ procedure Execute (Interp: in out Interpreter_Record) is
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end loop;
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Pop_Frame (Interp); -- done.
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Pop_Tops (Interp, 2);
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end Do_Let_Binding;
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procedure Do_Letast_Binding is
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pragma Inline (Do_Letast_Binding);
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X: aliased Object_Pointer;
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Y: aliased Object_Pointer;
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begin
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Push_Top (Interp, X'Unchecked_Access);
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Push_Top (Interp, Y'Unchecked_Access);
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X := Get_Frame_Operand(Interp.Stack); -- <bindings> and onward
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Y := Get_Frame_Result(Interp.Stack);
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if Y = Nil_Pointer then
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-- First call
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pragma Assert (Is_Cons(X)); -- Don't provoke this procedure if <bindings> is empty.
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Push_Frame (Interp, Opcode_Evaluate_Object, Get_Car(Get_Cdr(Get_Car(X))));
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else
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-- Subsequence calls
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-- Update the environment while evaluating <bindings>
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Put_Environment (Interp, Get_Car(Get_Car(X)), Get_Car(Y));
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X := Get_Cdr(X); -- next binding
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if Is_Cons(X) then
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-- More bingings to evaluate
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Set_Frame_Operand (Interp.Stack, X);
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Clear_Frame_Result (Interp.Stack);
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Push_Frame (Interp, Opcode_Evaluate_Object, Get_Car(Get_Cdr(Get_Car(X))));
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else
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-- No more bingings left
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Pop_Frame (Interp); -- Done
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end if;
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end if;
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Pop_Tops (Interp, 2);
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end Do_Letast_Binding;
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procedure Do_Let_Finish is
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pragma Inline (Do_Let_Finish);
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begin
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@ -913,14 +939,13 @@ begin
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when Opcode_Let_Binding =>
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Do_Let_Binding;
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when Opcode_Letast_Binding =>
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Do_Letast_Binding;
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when Opcode_Let_Evaluation =>
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Do_Let_Evaluation;
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when Opcode_Let_Finish =>
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Do_Let_Finish;
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--when Opcode_Finish_Letast_Syntax =>
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--when Opcode_Finish_Letrec_Syntax =>
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when Opcode_Finish_Or_Syntax =>
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Finish_Or_Syntax; -- Conditional
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@ -79,8 +79,7 @@ package body H2.Scheme is
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-- INTERNALLY-USED TYPES
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-----------------------------------------------------------------------------
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type Heap_Element_Pointer is access all Heap_Element;
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for Heap_Element_Pointer'Size use Object_Pointer_Bits; -- ensure that it can be overlayed by an ObjectPointer
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for Heap_Element_Pointer'Size use Object_Pointer_Bits; -- ensure that it can be overlaid by an ObjectPointer
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type Thin_Heap_Element_Array is array (1 .. Heap_Size'Last) of Heap_Element;
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type Thin_Heap_Element_Array_Pointer is access all Thin_Heap_Element_Array;
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@ -88,7 +87,7 @@ package body H2.Scheme is
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subtype Moved_Object_Record is Object_Record (Moved_Object, 0);
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subtype Opcode_Type is Object_Integer range 0 .. 18;
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subtype Opcode_Type is Object_Integer range 0 .. 19;
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Opcode_Exit: constant Opcode_Type := Opcode_Type'(0);
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Opcode_Evaluate_Result: constant Opcode_Type := Opcode_Type'(1);
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Opcode_Evaluate_Object: constant Opcode_Type := Opcode_Type'(2);
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@ -100,16 +99,17 @@ package body H2.Scheme is
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Opcode_Finish_Set_Syntax: constant Opcode_Type := Opcode_Type'(8);
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Opcode_Let_Binding: constant Opcode_Type := Opcode_Type'(9);
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Opcode_Let_Evaluation: constant Opcode_Type := Opcode_Type'(10);
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Opcode_Let_Finish: constant Opcode_Type := Opcode_Type'(11);
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Opcode_Letast_Binding: constant Opcode_Type := Opcode_Type'(10);
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Opcode_Let_Evaluation: constant Opcode_Type := Opcode_Type'(11);
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Opcode_Let_Finish: constant Opcode_Type := Opcode_Type'(12);
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Opcode_Apply: constant Opcode_Type := Opcode_Type'(12);
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Opcode_Read_Object: constant Opcode_Type := Opcode_Type'(13);
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Opcode_Read_List: constant Opcode_Type := Opcode_Type'(14);
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Opcode_Read_List_Cdr: constant Opcode_Type := Opcode_Type'(15);
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Opcode_Read_List_End: constant Opcode_Type := Opcode_Type'(16);
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Opcode_Close_List: constant Opcode_Type := Opcode_Type'(17);
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Opcode_Close_Quote: constant Opcode_Type := Opcode_Type'(18);
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Opcode_Apply: constant Opcode_Type := Opcode_Type'(13);
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Opcode_Read_Object: constant Opcode_Type := Opcode_Type'(14);
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Opcode_Read_List: constant Opcode_Type := Opcode_Type'(15);
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Opcode_Read_List_Cdr: constant Opcode_Type := Opcode_Type'(16);
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Opcode_Read_List_End: constant Opcode_Type := Opcode_Type'(17);
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Opcode_Close_List: constant Opcode_Type := Opcode_Type'(18);
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Opcode_Close_Quote: constant Opcode_Type := Opcode_Type'(19);
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-----------------------------------------------------------------------------
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-- COMMON OBJECTS
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@ -1650,7 +1650,7 @@ Ada.Text_IO.Put_Line ("Make_String...");
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Dummy := Make_Syntax (Interp.Self, Lambda_Syntax, Label_Lambda); -- "lamba"
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Dummy := Make_Syntax (Interp.Self, Let_Syntax, Label_Let); -- "let"
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Dummy := Make_Syntax (Interp.Self, Letast_Syntax, Label_Letast); -- "let*"
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Dummy := Make_Syntax (Interp.Self, Letrec_Syntax, Label_Letrec); -- "letrc"
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Dummy := Make_Syntax (Interp.Self, Letrec_Syntax, Label_Letrec); -- "letrec"
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Dummy := Make_Syntax (Interp.Self, Or_Syntax, Label_Or); -- "or"
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Interp.Symbol.Quote := Make_Syntax (Interp.Self, Quote_Syntax, Label_Quote); -- "quote"
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Interp.Symbol.Quasiquote := Make_Syntax (Interp.Self, Quasiquote_Syntax, Label_Quasiquote); -- "quasiquote"
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