617 lines
18 KiB
Ada
617 lines
18 KiB
Ada
separate (H2.Scheme.Execute)
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procedure Evaluate is
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--pragma Inline (Evaluate);
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Operand: aliased Object_Pointer;
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Car: aliased Object_Pointer;
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Cdr: aliased Object_Pointer;
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generic
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V: Object_Pointer;
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Opcode: Opcode_Type;
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procedure Generic_And_Or_Syntax;
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procedure Generic_And_Or_Syntax is
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begin
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-- (and <test1> <test2> ...)
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-- (and (= 2 2) (> 2 1)) ==> #t
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-- (and (= 2 2) (< 2 1)) ==> #f
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-- (and (= 2 2) (< 2 1) (= 3 3)) ==> #f
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-- (and 1 2 'c '(f g)) ==> (f g)
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-- (and) ==> #t
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Operand := Cdr; -- Skip "And"
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if Operand = Nil_Pointer then
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-- (and)
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Pop_Frame (Interp);
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Put_Frame_Result (Interp, Interp.Stack, V);
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elsif not Is_Cons(Operand) or else Get_Last_Cdr(Operand) /= Nil_Pointer then
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-- (and . 10)
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-- (and 1 2 . 10)
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Ada.Text_IO.Put_LINE ("FUCKING cDR FOR DEFINE");
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raise Syntax_Error;
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else
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Set_Frame_Opcode (Interp.Stack, Opcode);
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Set_Frame_Operand (Interp.Stack, Get_Cdr(Operand)); -- <test2> onwards
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Clear_Frame_Result (Interp.Stack);
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-- arrange to evaluate <test1>
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Push_Frame (Interp, Opcode_Evaluate_Object, Get_Car(Operand));
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end if;
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end Generic_And_Or_Syntax;
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procedure Evaluate_And_Syntax is new Generic_And_Or_Syntax(True_Pointer, Opcode_Finish_And_Syntax);
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procedure Evaluate_Or_Syntax is new Generic_And_Or_Syntax(False_Pointer, Opcode_Finish_Or_Syntax);
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procedure Evaluate_Define_Syntax is
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pragma Inline (Evaluate_Define_Syntax);
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begin
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-- TODO: limit the context where define can be used.
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-- (define x 10)
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-- (define (add x y) (+ x y)) -> (define add (lambda (x y) (+ x y)))
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Operand := Cdr; -- Skip "define"
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if not Is_Cons(Operand) or else not Is_Cons(Get_Cdr(Operand)) then
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-- e.g) (define)
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-- (define . 10)
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-- (define x . 10)
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Ada.Text_IO.Put_LINE ("TOO FEW ARGUMENTS FOR DEFINE");
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raise Syntax_Error;
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end if;
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Car := Get_Car(Operand);
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Cdr := Get_Cdr(Operand);
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if Is_Cons(Car) then
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-- define a function: (define (add x y) ...)
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null;
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elsif Is_Symbol(Car) then
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-- define a symbol: (define x ...)
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if Get_Cdr(Cdr) /= Nil_Pointer then
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Ada.Text_IO.Put_LINE ("TOO MANY ARGUMENTS FOR DEFINE");
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raise Syntax_Error;
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end if;
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Cdr := Get_Car(Cdr); -- Value
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-- Arrange to finish defining after value evaluation.
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Set_Frame_Opcode (Interp.Stack, Opcode_Finish_Define_Symbol);
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Set_Frame_Operand (Interp.Stack, Car);
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Clear_Frame_Result (Interp.Stack);
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-- Arrange to evalaute the value part
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Push_Frame (Interp, Opcode_Evaluate_Object, Cdr);
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else
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Ada.Text_IO.Put_LINE ("NO SYMBOL NOR ARGUMENT LIST AFTER DEFINE");
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raise Syntax_Error;
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end if;
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end Evaluate_Define_Syntax;
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procedure Evaluate_If_Syntax is
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pragma Inline (Evaluate_If_Syntax);
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begin
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-- (if <test> <consequent>)
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-- (if <test> <consequent> <alternate>)
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-- e.g) (if (> 3 2) 'yes)
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-- (if (> 3 2) 'yes 'no)
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-- (if (> 3 2) (- 3 2) (+ 3 2))
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Operand := Cdr; -- Skip "if"
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if Not Is_Cons(Operand) then
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-- e.g) (if)
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-- (if . 10)
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Ada.Text_IO.Put_LINE ("NO CONDITIONAL FOR IF");
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raise Syntax_Error;
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end if;
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Car := Get_Car(Operand); -- <test>
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Operand := Get_Cdr(Operand); -- cons cell containg <consequent>
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if not Is_Cons(Operand) then
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Ada.Text_IO.Put_Line ("NO ACTION FOR IF");
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raise Syntax_Error;
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end if;
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Cdr := Get_Cdr(Operand); -- cons cell containing <alternate>
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if Cdr = Nil_Pointer then
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-- no <alternate>. it's ok
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Ada.Text_IO.Put_Line ("NO ALTERNATE");
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null;
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elsif not Is_Cons(Cdr) then
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-- no <alternate> but reduncant cdr.
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-- (if (> 3 2) 3 . 99)
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Ada.Text_IO.Put_Line ("FUCKING CDR FOR IF");
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raise Syntax_Error;
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elsif Get_Cdr(Cdr) /= Nil_Pointer then
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-- (if (> 3 2) 3 2 . 99)
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-- (if (> 3 2) 3 2 99)
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Ada.Text_IO.Put_Line ("TOO MANY ARGUMENTS FOR IF");
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raise Syntax_Error;
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end if;
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-- Switch the current frame to execute action after <test> evaluation.
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Set_Frame_Opcode (Interp.Stack, Opcode_Finish_If_Syntax);
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Set_Frame_Operand (Interp.Stack, Operand);
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Clear_Frame_Result (Interp.Stack);
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-- Arrange to evalaute the conditional
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Push_Frame (Interp, Opcode_Evaluate_Object, Car);
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end Evaluate_If_Syntax;
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procedure Evaluate_Lambda_Syntax is
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pragma Inline (Evaluate_Lambda_Syntax);
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begin
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-- (lambda <formals> <body>)
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-- e.g) (lambda (x y) (+ x y))
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-- e.g) (lambda (x y . z) z)
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-- e.g) (lambda x (car x))
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Operand := Cdr; -- Skip "lambda". cons cell pointing to <formals>
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if not Is_Cons(Operand) then
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-- e.g) (lambda)
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-- (lambda . 10)
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Ada.Text_IO.Put_LINE ("FUCKNING CDR FOR LAMBDA");
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raise Syntax_Error;
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end if;
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Car := Get_Car(Operand); -- <formals>
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if Car = Nil_Pointer or else Is_Symbol(Car) then
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-- (lambda () ...) or (lambda x ...)
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-- nothing to do
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null;
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elsif Is_Cons(Car) then
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declare
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Formals: Object_Pointer := Car;
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V: Object_Pointer;
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begin
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Cdr := Formals;
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loop
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Car := Get_Car(Cdr); -- <formal argument>
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if not Is_Symbol(Car) then
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Ada.Text_IO.Put_Line ("WRONG FORMAL FOR LAMBDA");
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raise Syntax_Error;
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end if;
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-- Check for a duplication formal argument
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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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V := Formals;
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loop
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exit when V = Cdr;
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if Get_Car(V) = Car then
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Ada.Text_IO.Put_Line ("DUPLICATE FORMAL FOR LAMBDA");
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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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-- Move on to the next formal argument
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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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end;
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if Cdr /= Nil_Pointer and then not Is_Symbol(Cdr) then
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Ada.Text_IO.Put_Line ("FUCKING CDR IN FORMALS FOR LAMBDA");
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raise Syntax_Error;
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end if;
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else
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Ada.Text_IO.Put_Line ("INVALID FORMALS FOR LAMBDA");
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raise Syntax_Error;
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end if;
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Cdr := Get_Cdr(Operand); -- cons cell containing <body>
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if not Is_Cons(Cdr) then
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Ada.Text_IO.Put_Line ("NO BODY");
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raise Syntax_Error;
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end if;
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if Get_Last_Cdr(Cdr) /= Nil_Pointer then
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-- (lambda (x y) (+ x y) . 99)
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Ada.Text_IO.Put_Line ("FUCKING CDR IN BODY FOR LAMBDA");
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raise Syntax_Error;
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end if;
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declare
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Closure: Object_Pointer;
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begin
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Closure := Make_Closure(Interp.Self, Operand, Get_Frame_Environment(Interp.Stack));
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Pop_Frame (Interp); -- Done
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Put_Frame_Result (Interp, Interp.Stack, Closure);
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end;
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end Evaluate_Lambda_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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begin
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-- let <bindings> <body>
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Operand := Cdr; -- Skip "let".
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if not Is_Cons(Operand) then
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-- e.g) (let)
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-- (let . 10)
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Ada.Text_IO.Put_LINE ("FUCKNING CDR FOR LET");
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raise Syntax_Error;
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end if;
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Bindings := Get_Car(Operand); -- <bindings>
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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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Letbody := Get_Cdr(Operand); -- Cons cell to <body>
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if not Is_Cons(Letbody) or else Get_Last_Cdr(Letbody) /= Nil_Pointer then
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-- (let ((x 2)) )
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-- (let ((x 2)) . 99)
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-- (let ((x 2)) (+ x 2) . 99)
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Ada.Text_IO.Put_Line ("INVALID BODY FOR LET");
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raise Syntax_Error;
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end if;
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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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-- 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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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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Envir: aliased Object_Pointer;
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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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Clear_Frame_Result (Interp.Stack);
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-- Push a new environment onto the current frame.
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-- It's pushed even if <bindings> is empty because
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-- the new environment is still needed in such a case
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-- as shown in the first sample below.
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Envir := Make_Environment(Interp.Self, Get_Frame_Environment(Interp.Stack));
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Set_Frame_Environment (Interp.Stack, Envir);
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-- Some let samples:
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-- #1.
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-- (define x 99) ; define x in the root environment
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-- (let () (define x 100)) ; x is defined in the new environment.
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-- x ; this must be 99.
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--
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-- #2.
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-- (define x 10) ; x-outer
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-- (define y (let ((x (+ x 1))) x)) ; x-inner := x-outer + 1, y := x-inner
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-- y ; 11
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-- x ; 10
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--
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-- #3.
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-- (define x (let ((x x)) x))
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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_Top (Interp, Envir'Unchecked_Access);
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Envir := Get_Frame_Environment(Get_Frame_Parent(Interp.Stack));
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-- Create an array to hold the binding list and the evaluation result
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Cdr := Make_Array (Interp.Self, 3);
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Cdr.Pointer_Slot(1) := Car;
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-- The actual binding after evaluation must be performed in the
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-- new environment.
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Push_Frame (Interp, Opcode_Let_Binding, Cdr);
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-- But evaluation must be done in the current environment which is
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-- the environment before the environment update above.
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Push_Frame_With_Environment (Interp, Opcode_Let_Evaluation, Cdr, Envir);
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Pop_Tops (Interp, 1);
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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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Envir: Object_Pointer;
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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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Clear_Frame_Result (Interp.Stack);
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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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else
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-- <bindings> is empty. push the new environment
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-- for <body> evaluation.
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Envir := Make_Environment(Interp.Self, Get_Frame_Environment(Interp.Stack));
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Set_Frame_Environment (Interp.Stack, Envir);
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end if;
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end Evaluate_Letast_Syntax;
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procedure Evaluate_Letrec_Syntax is
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pragma Inline (Evaluate_Letrec_Syntax);
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Envir: Object_Pointer;
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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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Clear_Frame_Result (Interp.Stack);
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-- Push a new environment.
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Envir := Make_Environment(Interp.Self, Get_Frame_Environment(Interp.Stack));
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Set_Frame_Environment (Interp.Stack, Envir);
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if Car /= Nil_Pointer then
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-- <bindings> is not empty
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-- Arrange to perform evaluataion and binding in the
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-- new environment created.
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Cdr := Make_Array (Interp.Self, 3);
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Cdr.Pointer_Slot(1) := Car;
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Push_Frame (Interp, Opcode_Let_Binding, Cdr);
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Push_Frame (Interp, Opcode_Let_Evaluation, Cdr);
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end if;
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end Evaluate_Letrec_Syntax;
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procedure Evaluate_Quote_Syntax is
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pragma Inline (Evaluate_Quote_Syntax);
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begin
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Operand := Cdr; -- Skip "quote". Get the first argument.
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if not Is_Cons(Operand) then
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-- e.g) (quote)
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-- (quote . 10)
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Ada.Text_IO.Put_LINE ("FUCKNING CDR FOR QUOTE");
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raise Syntax_Error;
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elsif Get_Cdr(Operand) /= Nil_Pointer then
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Ada.Text_IO.Put_LINE ("WRONG NUMBER OF ARGUMENTS FOR QUOTE");
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raise Syntax_Error;
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end if;
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Pop_Frame (Interp); -- Done
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Put_Frame_Result (Interp, Interp.Stack, Get_Car(Operand));
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end Evaluate_Quote_Syntax;
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procedure Evaluate_Set_Syntax is
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pragma Inline (Evaluate_Set_Syntax);
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begin
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-- (set! <variable> <expression>)
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-- e.g) (set! x 10)
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Operand := Cdr; -- Skip "set!"
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if not Is_Cons(Operand) or else not Is_Cons(Get_Cdr(Operand)) then
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-- e.g) (set!)
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-- (set . 10)
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-- (set x . 10)
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Ada.Text_IO.Put_LINE ("TOO FEW ARGUMENTS FOR SET!");
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raise Syntax_Error;
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end if;
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Car := Get_Car(Operand); -- <variable>
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Cdr := Get_Cdr(Operand); -- cons cell to <expression>
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if Is_Symbol(Car) then
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if Get_Cdr(Cdr) /= Nil_Pointer then
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Ada.Text_IO.Put_LINE ("TOO MANY ARGUMENTS FOR SET!");
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raise Syntax_Error;
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end if;
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Cdr := Get_Car(Cdr); -- <expression>
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-- Arrange to finish setting a variable after <expression> evaluation.
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Set_Frame_Opcode (Interp.Stack, Opcode_Set_Finish);
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Set_Frame_Operand (Interp.Stack, Car);
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Clear_Frame_Result (Interp.Stack);
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-- Arrange to evalaute the value part
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Push_Frame (Interp, Opcode_Evaluate_Object, Cdr);
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else
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Ada.Text_IO.Put_LINE ("INVALID SYMBOL AFTER SET!");
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raise Syntax_Error;
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end if;
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end Evaluate_Set_Syntax;
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begin
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Push_Top (Interp, Operand'Unchecked_Access);
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Push_Top (Interp, Car'Unchecked_Access);
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Push_Top (Interp, Cdr'Unchecked_Access);
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<<Start_Over>>
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Operand := Get_Frame_Operand(Interp.Stack);
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declare
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f: object_word;
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for f'address use interp.stack'address;
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o: object_word;
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for o'address use operand'address;
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begin
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ada.text_io.put ("Frame" & object_word'image(f) & " EVALUATE OPERAND" & object_word'image(o) & " ");
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print (interp, operand);
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ada.text_io.put (" CURRENT RESULT ");
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print (interp, get_Frame_result(interp.stack));
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end;
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if not Is_Normal_Pointer(Operand) then
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-- integer, character, specal pointers
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-- TODO: some normal pointers may point to literal objects. e.g.) bignum
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goto Literal;
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end if;
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case Operand.Tag is
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when Symbol_Object => -- Is_Symbol(Operand)
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-- TODO: find it in the Environment hierarchy.. not in the current environemnt.
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Car := Get_Environment (Interp.Self, Operand);
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if Car = null then
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-- unbound
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Ada.Text_IO.Put_Line ("Unbound symbol....");
|
|
Print (Interp, Operand);
|
|
raise Evaluation_Error;
|
|
else
|
|
-- symbol found in the environment
|
|
Operand := Car;
|
|
goto Literal; -- In fact, this is not a literal, but can be handled in the same way
|
|
end if;
|
|
|
|
when Cons_Object => -- Is_Cons(Operand)
|
|
Car := Get_Car(Operand);
|
|
Cdr := Get_Cdr(Operand);
|
|
if Is_Syntax(Car) then
|
|
-- special syntax symbol. normal evaluate rule doesn't
|
|
-- apply for special syntax objects.
|
|
|
|
case Car.Scode is
|
|
when And_Syntax =>
|
|
Evaluate_And_Syntax;
|
|
|
|
when Begin_Syntax =>
|
|
Operand := Cdr; -- Skip "begin"
|
|
|
|
if Operand = Nil_Pointer then
|
|
-- (begin)
|
|
Pop_Frame (Interp);
|
|
-- Return nil to the upper frame for (begin).
|
|
Put_Frame_Result (Interp, Interp.Stack, Nil_Pointer);
|
|
else
|
|
if Get_Last_Cdr(Operand) /= Nil_Pointer then
|
|
Ada.Text_IO.Put_LINE ("FUCKNING CDR FOR BEGIN");
|
|
raise Syntax_Error;
|
|
end if;
|
|
|
|
Set_Frame_Opcode (Interp.Stack, Opcode_Grouped_Call);
|
|
Set_Frame_Operand (Interp.Stack, Operand);
|
|
Clear_Frame_Result (Interp.Stack);
|
|
end if;
|
|
|
|
--if (Interp.Trait.Trait_Bits and No_Optimization) = 0 then
|
|
-- -- I call Evaluate_Group for optimization here.
|
|
-- Evaluate_Group; -- for optimization only. not really needed.
|
|
-- -- I can jump to Start_Over because Evaluate_Group called
|
|
-- -- above pushes an Opcode_Evaluate_Object frame.
|
|
-- pragma Assert (Get_Frame_Opcode(Interp.Stack) = Opcode_Evaluate_Object);
|
|
-- goto Start_Over; -- for optimization only. not really needed.
|
|
--end if;
|
|
|
|
when Define_Syntax =>
|
|
Evaluate_Define_Syntax;
|
|
|
|
when If_Syntax =>
|
|
Evaluate_If_Syntax;
|
|
|
|
when Lambda_Syntax =>
|
|
Evaluate_Lambda_Syntax;
|
|
|
|
when Let_Syntax =>
|
|
Evaluate_Let_Syntax;
|
|
|
|
when Letast_Syntax =>
|
|
Evaluate_Letast_Syntax;
|
|
|
|
when Letrec_Syntax =>
|
|
Evaluate_Letrec_Syntax;
|
|
|
|
when Or_Syntax =>
|
|
Evaluate_Or_Syntax;
|
|
|
|
when Quote_Syntax =>
|
|
Evaluate_Quote_Syntax;
|
|
|
|
when Set_Syntax => -- set!
|
|
Evaluate_Set_Syntax;
|
|
|
|
when others =>
|
|
Ada.Text_IO.Put_Line ("Unknown syntax");
|
|
--Set_Frame_Opcode (Interp.Stack, Opcode_Evaluate_Syntax); -- Switch to syntax evaluation
|
|
raise Internal_Error;
|
|
end case;
|
|
else
|
|
-- procedure call
|
|
-- (<operator> <operand1> ...)
|
|
if Get_Last_Cdr(Operand) /= Nil_Pointer then
|
|
Ada.Text_IO.Put_Line ("ERROR: FUCKING CDR FOR PROCEDURE CALL.$$$$");
|
|
raise Syntax_Error;
|
|
end if;
|
|
|
|
-- Create a cons cell whose 'car' holds arguments and
|
|
-- 'cdr' holds evaluation results before applying them.
|
|
Cdr := Make_Cons (Interp.Self, Cdr, Nil_Pointer);
|
|
|
|
-- Set it as a frame operand
|
|
Set_Frame_Opcode (Interp.Stack, Opcode_Procedure_Call);
|
|
Set_Frame_Operand (Interp.Stack, Cdr);
|
|
Clear_Frame_Result (Interp.Stack);
|
|
|
|
-- Arrange to evaluate <operator> first.
|
|
Push_Frame (Interp, Opcode_Evaluate_Object, Car);
|
|
end if;
|
|
|
|
when others =>
|
|
-- normal literal object
|
|
goto Literal;
|
|
end case;
|
|
goto Done;
|
|
|
|
<<Literal>>
|
|
Pop_Frame (Interp); -- done
|
|
declare
|
|
w: object_word;
|
|
for w'address use operand'address;
|
|
begin
|
|
Ada.Text_IO.Put ("Return => (" & object_word'image(w) & ") =>" );
|
|
Print (Interp, Operand);
|
|
end;
|
|
Put_Frame_Result (Interp, Interp.Stack, Operand);
|
|
goto Done;
|
|
|
|
<<Done>>
|
|
Pop_Tops (Interp, 3);
|
|
end Evaluate;
|