1095 lines
34 KiB
Ada
1095 lines
34 KiB
Ada
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separate (H2.Scheme)
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procedure Execute (Interp: in out Interpreter_Record) is
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LC: IO_Character_Record renames Interp.Input.Iochar;
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procedure Evaluate_Result is
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pragma Inline (Evaluate_Result);
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begin
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-- The result from the previous frame is stored in the current frame.
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-- This procedure takes the result and switch it to an operand and clears it.
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-- It is used to evaluate the result of Read_Object in principle.
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-- It takes only the head(car) element of the result chain.
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-- Calling this function to evaluate the result of any arbitrary frame
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-- other than 'Read_Object' is not recommended.
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Set_Frame_Operand (Interp.Stack, Get_Car(Get_Frame_Result(Interp.Stack)));
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Clear_Frame_Result (Interp.Stack);
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Set_Frame_Opcode (Interp.Stack, Opcode_Evaluate_Object);
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end Evaluate_Result;
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-- ----------------------------------------------------------------
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generic
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V: Object_Pointer;
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procedure Evaluate_Up_To;
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procedure Evaluate_Up_To is
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X: Object_Pointer;
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Y: Object_Pointer;
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begin
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X := Get_Frame_Operand(Interp.Stack);
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Y := Get_Frame_Result(Interp.Stack);
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-- Evaluate_And_Syntax/Evaluate_Or_Syntax has arranged to
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-- evaluate <test1>. Y must not be Nil_Pointer even at the
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-- first time this procedure is called,
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pragma Assert (Is_Cons(Y));
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pragma Assert (Get_Cdr(Y) = Nil_Pointer); -- ensure 1 resul
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Y := Get_Car(Y); -- actual result
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if Y /= V and then Is_Cons(X) then
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-- The result is not what I look for.
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-- Yet there are still more tests to evaluate.
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Set_Frame_Operand (Interp.Stack, Get_Cdr(X));
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Clear_Frame_Result (Interp.Stack);
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Push_Frame (Interp, Opcode_Evaluate_Object, Get_Car(X));
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else
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-- Return the result of the last expression evaluated.
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Pop_Frame (Interp);
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Put_Frame_Result (Interp, Interp.Stack, Y);
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end if;
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end Evaluate_Up_To;
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procedure Finish_And_Syntax is new Evaluate_Up_To(False_Pointer);
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procedure Finish_Or_Syntax is new Evaluate_Up_To(True_Pointer);
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-- ----------------------------------------------------------------
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procedure Finish_Define_Symbol is
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pragma Inline (Finish_Define_Symbol);
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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); -- symbol
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pragma Assert (Is_Symbol(X));
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Y := Get_Frame_Result(Interp.Stack); -- value list
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pragma Assert (Get_Cdr(Y) = Nil_Pointer); -- ensure only 1 return value
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Y := Get_Car(Y); -- the first value
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Put_Environment (Interp, X, Y);
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Pop_Frame (Interp); -- Done
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Put_Frame_Result (Interp, Interp.Stack, Y);
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Pop_Tops (Interp, 2);
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end Finish_Define_Symbol;
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procedure Finish_If_Syntax is
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pragma Inline (Finish_If_Syntax);
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X: aliased Object_Pointer;
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Y: aliased Object_Pointer;
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Z: 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); -- cons cell containing <consequent>
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pragma Assert (Is_Cons(X));
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Y := Get_Frame_Result(Interp.Stack); -- result list of <test>
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pragma Assert (Get_Cdr(Y) = Nil_Pointer); -- ensure only 1 return value
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Y := Get_Car(Y); -- the first value
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if Y = False_Pointer then
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-- <test> evaluated to #f.
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X := Get_Cdr(X); -- cons cell containing <alternate>
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if Is_Cons(X) then
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-- Switch the current current to evaluate <alternate>
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-- Keep the environment untouched.
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Set_Frame_Opcode (Interp.Stack, Opcode_Evaluate_Object);
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Set_Frame_Operand (Interp.Stack, Get_Car(X));
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Clear_Frame_Result (Interp.Stack);
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else
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Pop_Frame (Interp);
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-- Return nil if no <alternate> is specified
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Put_Frame_Result (Interp, Interp.Stack, Nil_Pointer);
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end if;
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else
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-- All values except #f are true values. evaluate <consequent>
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-- Switch the current current to evaluate <consequent>
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-- Keep the environment untouched.
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Set_Frame_Opcode (Interp.Stack, Opcode_Evaluate_Object);
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Set_Frame_Operand (Interp.Stack, Get_Car(X));
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Clear_Frame_Result (Interp.Stack);
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end if;
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Pop_Tops (Interp, 2);
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end Finish_If_Syntax;
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-- ----------------------------------------------------------------
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procedure Do_Procedure_Call is
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pragma Inline (Do_Procedure_Call);
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X: aliased Object_Pointer;
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S: aliased Object_Pointer;
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R: 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, S'Unchecked_Access);
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Push_Top (Interp, R'Unchecked_Access);
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X := Get_Frame_Operand(Interp.Stack);
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pragma Assert (Is_Cons(X));
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-- When this procedure is called for the first time,
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-- the first argument must be at the head of the list that
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-- 'S' points to. it's because <operator> evaluation frame
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-- is pushed by Evaluate().
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S := Get_Car(X);
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R := Get_Cdr(X);
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-- Threfore, the frame result is for <operator> for the first call.
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R := Make_Cons(Interp.Self, Get_Car(Get_Frame_Result(Interp.Stack)), R);
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Clear_Frame_Result (Interp.Stack);
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if Is_Cons(S) then
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Set_Cdr (X, R); -- chain the result
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Set_Car (X, Get_Cdr(S)); -- remember the next <operator> to evaluate
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Push_Frame (Interp, Opcode_Evaluate_Object, Get_Car(S));
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else
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-- no more argument to evaluate.
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-- apply the evaluated arguments to the evaluated operator.
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Set_Frame_Opcode (Interp.Stack, Opcode_Apply);
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Set_Frame_Operand (Interp.Stack, Reverse_Cons(R));
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end if;
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Pop_Tops (Interp, 3);
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end Do_Procedure_Call;
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-- ----------------------------------------------------------------
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procedure Do_Grouped_Call is
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X: Object_Pointer;
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begin
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X := Get_Frame_Operand(Interp.Stack);
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pragma Assert (Is_Cons(X)); -- The caller must ensure this.
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--if Is_Cons(X) then
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Set_Frame_Opcode (Interp.Stack, Opcode_Grouped_Call_Finish);
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Set_Frame_Operand (Interp.Stack, Get_Cdr(X));
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Clear_Frame_Result (Interp.Stack);
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Push_Frame (Interp, Opcode_Evaluate_Object, Get_Car(X));
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--else
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-- -- Nothing to evaluate.
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-- Pop_Frame (Interp);
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-- Put_Frame_Result (Interp, Interp.Stack, Nil_Pointer);
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--end if;
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end Do_Grouped_Call;
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procedure Do_Grouped_Call_Finish is
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X: Object_Pointer;
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R: Object_Pointer;
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begin
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X := Get_Frame_Operand(Interp.Stack);
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if Is_Cons(X) then
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Set_Frame_Opcode (Interp.Stack, Opcode_Grouped_Call_Finish);
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Set_Frame_Operand (Interp.Stack, Get_Cdr(X));
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Clear_Frame_Result (Interp.Stack);
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Push_Frame (Interp, Opcode_Evaluate_Object, Get_Car(X));
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else
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-- Nothing more to evaluate.
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R := Get_Frame_Result(Interp.Stack);
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declare
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w: object_word;
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for w'address use interp.stack'address;
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begin
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ada.text_io.put_line ("Frame" & object_word'image(w) & " " & Opcode_Type'Image(Get_Frame_Opcode(Interp.Stack)));
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ada.text_io.put (" EVAL-GROUP RESULT ");
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print (Interp, R);
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end;
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-- There must be only 1 return value chained in the Group frame.
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pragma Assert (Get_Cdr(R) = Nil_Pointer);
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Pop_Frame (Interp);
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-- Return the last result to the upper frame
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Put_Frame_Result (Interp, Interp.Stack, Get_Car(R));
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end if;
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end Do_Grouped_Call_Finish;
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-- ----------------------------------------------------------------
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procedure Do_Let_Evaluation is
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pragma Inline (Do_Let_Evaluation);
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X: aliased Object_Pointer;
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S: aliased Object_Pointer;
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R: 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, S'Unchecked_Access);
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Push_Top (Interp, R'Unchecked_Access);
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X := Get_Frame_Operand(Interp.Stack);
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pragma Assert (Is_Array(X));
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R := X.Pointer_Slot(3);
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if R = Nil_Pointer then
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-- First call;
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X.Pointer_Slot(2) := X.Pointer_Slot(1);
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else
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-- Subsequent calls. Store the result in the room created
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-- in the previous call.
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pragma Assert (Is_Cons(R));
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Set_Car (R, Get_Car(Get_Frame_Result(Interp.Stack)));
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end if;
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S := X.Pointer_Slot(2);
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if Is_Cons(S) then
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-- Handle each binding.
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-- Make an empty room to hold the result on the next call
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R := Make_Cons (Interp.Self, Nil_Pointer, R);
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X.Pointer_Slot(3) := R;
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-- Remember the next <operator> to evaluate
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X.Pointer_Slot(2) := Get_Cdr(S);
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-- Say, <bindings> is ((x 2) (y 2)).
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-- for the first call, Get_Car(S) is (x 2).
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-- To get x, Get_Car(Get_Car(S))
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-- To get 2, Get_Car(Get_Cdr(Get_Car(S)))
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Push_Frame (Interp, Opcode_Evaluate_Object, Get_Car(Get_Cdr(Get_Car(S))));
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else
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-- No more binding to handle.
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Pop_Frame (Interp);
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-- The operands at the Let_Evaluation and the Let_Binding frame
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-- must be the identical objects. this way, i don't need to carry
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-- over the binding result to the Let_Binding frame.
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pragma Assert (X = Get_Frame_Operand(Interp.Stack));
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pragma Assert (Get_Frame_Opcode(Interp.Stack) = Opcode_Let_Binding);
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--X := Get_Frame_Operand(Interp.Stack);
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--pragma Assert (Is_Array(X));
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--pragma Assert (X.Pointer_Slot(3) = Nil_Pointer);
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--X.Pointer_Slot(3) := R;
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end if;
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Pop_Tops (Interp, 3);
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end Do_Let_Evaluation;
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procedure Do_Let_Binding is
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pragma Inline (Do_Let_Binding);
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X: aliased Object_Pointer;
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S: aliased Object_Pointer;
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R: 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, S'Unchecked_Access);
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Push_Top (Interp, R'Unchecked_Access);
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X := Get_Frame_Operand(Interp.Stack); -- <bindings> and onward
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pragma Assert (Is_Array(X));
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S := X.Pointer_Slot(1);
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R := X.Pointer_Slot(3);
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R := Reverse_Cons(R);
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while Is_Cons(S) loop
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pragma Assert (Is_Cons(R));
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Put_Environment (Interp, Get_Car(Get_Car(S)), Get_Car(R));
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S := Get_Cdr(S);
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R := Get_Cdr(R);
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end loop;
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Pop_Frame (Interp); -- done.
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pragma Assert (Get_Frame_Opcode(Interp.Stack) = Opcode_Let_Finish);
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Pop_Tops (Interp, 3);
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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: Object_Pointer;
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begin
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X := Get_Frame_Operand(Interp.Stack); -- <bindings> and onward
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-- Don't call this procedure if <bindings> is empty. The caller must ensure this
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pragma Assert (Is_Cons(X));
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Set_Frame_Opcode (Interp.Stack, Opcode_Letast_Binding_Finish);
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Push_Frame (Interp, Opcode_Evaluate_Object, Get_Car(Get_Cdr(Get_Car(X))));
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end Do_Letast_Binding;
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procedure Do_Letast_Binding_Finish is
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pragma Inline (Do_Letast_Binding_Finish);
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X: aliased Object_Pointer;
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Y: aliased Object_Pointer;
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Envir: 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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Push_Top (Interp, Envir'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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-- Update the environment while evaluating <bindings>
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-- Push a new environment for each binding.
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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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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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-- the next evaluation must be done in the environment where the
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-- current binding has been made.
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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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-- Update the environment of the Let_Finish frame.
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pragma Assert (Get_Frame_Opcode(Interp.Stack) = Opcode_Let_Finish);
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Set_Frame_Environment (Interp.Stack, Envir);
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end if;
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Pop_Tops (Interp, 3);
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end Do_Letast_Binding_Finish;
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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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pragma Assert (Get_Frame_Result(Interp.Stack) = Nil_Pointer);
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-- Evaluate_Let_Syntax has places <body> in the operand of this frame.
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-- <body> can be evaluated as if it's in 'begin'.
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--Set_Frame_Opcode (Interp.Stack, Opcode_Evaluate_Group);
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Set_Frame_Opcode (Interp.Stack, Opcode_Grouped_Call);
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end Do_Let_Finish;
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-- --------------------------------------------------------------------
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procedure Do_Set_Finish is
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pragma Inline (Do_Set_Finish);
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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); -- symbol
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Y := Get_Car(Get_Frame_Result(Interp.Stack)); -- value
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ada.text_io.put ("%%%%% FINISH SET SYNTAX => ");
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print (interp, Get_Frame_Result(Interp.Stack));
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pragma Assert (Is_Symbol(X));
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pragma Assert (Get_Cdr(Get_Frame_Result(Interp.Stack)) = Nil_Pointer);
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if Set_Environment(Interp.Self, X, Y) = null then
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Ada.Text_IO.PUt_LINE ("ERROR: UNBOUND SYMBOL");
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raise Evaluation_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, Y);
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Pop_Tops (Interp, 2);
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end Do_Set_Finish;
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procedure Evaluate is separate;
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procedure Apply is separate;
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procedure Unfetch_Character is
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pragma Inline (Unfetch_Character);
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pragma Assert (not Interp.LC_Unfetched);
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begin
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Interp.LC_Unfetched := Standard.True;
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end Unfetch_Character;
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procedure Fetch_Character is
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begin
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-- TODO: calculate Interp.Input.Row, Interp.Input.Column
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if Interp.Input.Pos >= Interp.Input.Last then
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if Interp.Input.Flags /= 0 then
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-- An error has occurred or EOF has been reached previously.
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-- Note calling this procedure after EOF results in an error.
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Interp.Input.Iochar := (Error_Character, Object_Character'First);
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--return;
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raise IO_Error;
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end if;
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Interp.Input.Pos := Interp.Input.Data'First - 1;
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begin
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Read (Interp.Input.Stream.all, Interp.Input.Data, Interp.Input.Last);
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exception
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when others =>
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-- The callee can raise an exception upon errors.
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-- If an exception is raised, data read into the buffer
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-- is also ignored.
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Interp.Input.Flags := Interp.Input.Flags and IO_Error_Occurred;
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Interp.Input.Iochar := (Error_Character, Object_Character'First);
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--return;
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raise IO_Error;
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end;
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if Interp.Input.Last < Interp.Input.Data'First then
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-- The callee must read 0 bytes on EOF
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Interp.Input.Flags := Interp.Input.Flags and IO_End_Reached;
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Interp.Input.Iochar := (End_Character, Object_Character'First);
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return;
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end if;
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end if;
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Interp.Input.Pos := Interp.Input.Pos + 1;
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Interp.Input.Iochar := (Normal_Character, Interp.Input.Data(Interp.Input.Pos));
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end Fetch_Character;
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function Is_White_Space (X: in Object_Character) return Standard.Boolean is
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begin
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return X = Ch.Space or else X = Ch.HT or else X = Ch.VT or else
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X = Ch.CR or else X = Ch.LF or else X = Ch.FF;
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end Is_White_Space;
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function Is_Delimiter (X: in Object_Character) return Standard.Boolean is
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begin
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return X = Ch.Left_Parenthesis or else X = Ch.Right_Parenthesis or else
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X = Ch.Quotation or else X = Ch.Semicolon or else
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Is_White_Space(X);
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end Is_Delimiter;
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procedure Skip_Spaces_And_Comments is
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begin
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loop
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exit when LC.Kind /= Normal_Character;
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-- Normal character
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if Is_White_Space(LC.Value) then
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Fetch_Character;
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elsif LC.Value = Ch.Semicolon then
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-- Comment.
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loop
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Fetch_Character;
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exit when LC.Kind = End_Character; -- EOF before LF
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if LC.Kind = Normal_Character and then LC.Value = Ch.LF then -- TODO: handle different line ending convention
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Fetch_Character; -- Read the next character after LF
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exit;
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end if;
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end loop;
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else
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exit;
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end if;
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end loop;
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end Skip_Spaces_And_Comments;
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procedure Fetch_Token is
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Tmp: Object_Character_Array(1..10); -- large enough???
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begin
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if not Interp.LC_Unfetched then
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Fetch_Character;
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else
|
|
-- Reuse the last character unfetched
|
|
Interp.LC_Unfetched := Standard.False;
|
|
end if;
|
|
Skip_Spaces_And_Comments;
|
|
if LC.Kind /= Normal_Character then
|
|
Token.Set (Interp, End_Token);
|
|
return;
|
|
end if;
|
|
|
|
-- TODO: Pass Token Location when calling Token.Set
|
|
|
|
-- Use Ch.Pos.XXX values instead of Ch.XXX values as gnat complained that
|
|
-- Ch.XXX values are not static. For this reason, "case LC.Value is ..."
|
|
-- changed to use Object_Character'Pos(LC.Value).
|
|
case Object_Character'Pos(LC.Value) is
|
|
|
|
when Ch.Pos.Left_Parenthesis =>
|
|
Token.Set (Interp, Left_Parenthesis_Token, LC.Value);
|
|
|
|
when Ch.Pos.Right_Parenthesis =>
|
|
Token.Set (Interp, Right_Parenthesis_Token, LC.Value);
|
|
|
|
when Ch.Pos.Period =>
|
|
Token.Set (Interp, Period_Token, LC.Value);
|
|
|
|
when Ch.Pos.Apostrophe =>
|
|
Token.Set (Interp, Single_Quote_Token, LC.Value);
|
|
|
|
when Ch.Pos.Number_Sign =>
|
|
Fetch_Character;
|
|
if LC.Kind /= Normal_Character then
|
|
-- ended prematurely.
|
|
-- TODO: Set Error code, Error Number.... Error location
|
|
raise Syntax_Error;
|
|
end if;
|
|
|
|
-- #t
|
|
-- #f
|
|
-- #\C -- character
|
|
-- #\xHHHH -- unicode
|
|
-- #\xHHHHHHHH -- unicode
|
|
-- #( ) -- vector
|
|
-- #[ ] -- list
|
|
-- #{ } -- hash table
|
|
-- #< > -- xxx
|
|
|
|
case Object_Character'Pos(LC.Value) is
|
|
when Ch.Pos.LC_T => -- #t
|
|
Token.Set (Interp, True_Token, Ch.Number_Sign);
|
|
Token.Append_Character (Interp, LC.Value);
|
|
|
|
when Ch.Pos.LC_F => -- #f
|
|
Token.Set (Interp, False_Token, Ch.Number_Sign);
|
|
Token.Append_Character (Interp, LC.Value);
|
|
|
|
when Ch.Pos.Backslash => -- #\C, #\space, #\newline
|
|
Fetch_Character;
|
|
if LC.Kind /= Normal_Character then
|
|
ada.text_io.put_line ("ERROR: NO CHARACTER AFTER #\");
|
|
raise Syntax_Error;
|
|
end if;
|
|
Token.Set (Interp, Character_Token, LC.Value);
|
|
|
|
loop
|
|
Fetch_Character;
|
|
if LC.Kind /= Normal_Character or else
|
|
Is_Delimiter(LC.Value) then
|
|
Unfetch_Character;
|
|
exit;
|
|
end if;
|
|
Token.Append_Character (Interp, LC.Value);
|
|
end loop;
|
|
|
|
if Interp.Token.Value.Last > 1 then
|
|
-- TODO: case insensitive match. binary search for more diverse words
|
|
-- TODO: #\xHHHH....
|
|
if Interp.Token.Value.Ptr.all(1..Interp.Token.Value.Last) = Label_Newline then
|
|
Token.Set (Interp, Character_Token, Ch.LF); -- reset the token to LF
|
|
elsif Interp.Token.Value.Ptr.all(1..Interp.Token.Value.Last) = Label_Space then
|
|
Token.Set (Interp, Character_Token, Ch.Space); -- reset the token to Space
|
|
else
|
|
-- unknown character name.
|
|
ada.text_io.put ("ERROR: UNKNOWN CHARACTER NAME ");
|
|
for I in 1 .. interp.token.value.last loop
|
|
ada.text_io.put (standard.character'val(object_character'pos(interp.token.value.ptr.all(i))));
|
|
end loop;
|
|
ada.text_io.new_line;
|
|
|
|
raise Syntax_Error;
|
|
end if;
|
|
end if;
|
|
|
|
--when Ch.Pos.Left_Parenthesis => -- #(
|
|
-- Token.Set (Interp, Vector_Token, Ch.Number_Sign);
|
|
-- Token.Append_Character (Interp, LC.Value);
|
|
|
|
--when Ch.Pos.Left_Bracket => -- $[
|
|
-- Token.Set (Interp, List_Token, Ch.Number_Sign);
|
|
-- Token.Append_Character (Interp, LC.Value);
|
|
|
|
--when Ch.Pos.Left_Bracket => -- ${
|
|
-- Token.Set (Interp, Table_Token, Ch.Number_Sign);
|
|
-- Token.Append_Character (Interp, LC.Value);
|
|
|
|
when others =>
|
|
-- unknown #letter
|
|
-- TODO: Set Error code, Error Number.... Error location
|
|
raise Syntax_Error;
|
|
|
|
end case;
|
|
|
|
when Ch.Pos.Quotation =>
|
|
Fetch_Character;
|
|
Token.Set (Interp, String_Token);
|
|
loop
|
|
if LC.Kind /= Normal_Character then
|
|
-- String ended prematurely.
|
|
-- TODO: Set Error code, Error Number.... Error location
|
|
raise Syntax_Error;
|
|
end if;
|
|
|
|
if LC.Value = Ch.Backslash then
|
|
Fetch_Character;
|
|
if LC.Kind /= Normal_Character then
|
|
-- String ended prematurely.
|
|
-- TODO: Set Error code, Error Number.... Error location
|
|
raise Syntax_Error;
|
|
end if;
|
|
-- TODO: escape letters??? \n \r \\ etc....
|
|
Token.Append_Character (Interp, LC.Value);
|
|
elsif LC.Value = Ch.Quotation then
|
|
exit;
|
|
else
|
|
Token.Append_Character (Interp, LC.Value);
|
|
Fetch_Character;
|
|
end if;
|
|
end loop;
|
|
|
|
|
|
when Ch.Pos.Zero .. Ch.Pos.Nine =>
|
|
-- TODO; negative number, floating-point number, bignum, hexdecimal, etc
|
|
Token.Set (Interp, Integer_Token);
|
|
loop
|
|
Token.Append_Character (Interp, LC.Value);
|
|
Fetch_Character;
|
|
if LC.Kind /= Normal_Character or else
|
|
LC.Value not in Ch.Zero .. Ch.Nine then
|
|
-- Unfetch the last character
|
|
Unfetch_Character;
|
|
exit;
|
|
end if;
|
|
end loop;
|
|
|
|
when Ch.Pos.Plus_Sign | Ch.Pos.Minus_Sign =>
|
|
|
|
Tmp(1) := LC.Value;
|
|
|
|
Fetch_Character;
|
|
if LC.Kind = Normal_Character and then
|
|
LC.Value in Ch.Zero .. Ch.Nine then
|
|
Token.Set (Interp, Integer_Token, Tmp(1..1));
|
|
loop
|
|
Token.Append_Character (Interp, LC.Value);
|
|
Fetch_Character;
|
|
if LC.Kind /= Normal_Character or else
|
|
LC.Value not in Ch.Zero .. Ch.Nine then
|
|
Unfetch_Character;
|
|
exit;
|
|
end if;
|
|
end loop;
|
|
else
|
|
Token.Set (Interp, Identifier_Token, Tmp(1..1));
|
|
loop
|
|
-- TODO: more characters
|
|
if LC.Kind /= Normal_Character or else
|
|
Is_Delimiter(LC.Value) then
|
|
Unfetch_Character;
|
|
exit;
|
|
end if;
|
|
|
|
Token.Append_Character (Interp, LC.Value);
|
|
Fetch_Character;
|
|
end loop;
|
|
end if;
|
|
|
|
when others =>
|
|
Token.Set (Interp, Identifier_Token);
|
|
loop
|
|
Token.Append_Character (Interp, LC.Value);
|
|
Fetch_Character;
|
|
--exit when not Is_Ident_Char(C.Value);
|
|
-- TODO: more characters
|
|
if LC.Kind /= Normal_Character or else
|
|
Is_Delimiter(LC.Value) then
|
|
Unfetch_Character;
|
|
exit;
|
|
end if;
|
|
end loop;
|
|
end case;
|
|
|
|
--Ada.Text_IO.Put (">>>>>>>>>>>>>>>>>>>>>>> Token: " & Interp.Token.Value.Ptr(1..Interp.Token.Value.Last));
|
|
end Fetch_Token;
|
|
|
|
procedure Read_List is
|
|
pragma Inline (Read_List);
|
|
V: aliased Object_Pointer;
|
|
begin
|
|
-- This procedure reads each token in a list.
|
|
-- If the list contains no period, this procedure reads up to the
|
|
-- closing right paranthesis; If a period is contained, it transfers
|
|
-- the control over to Read_List_Cdr.
|
|
|
|
Fetch_Token;
|
|
|
|
--Push_Top (Interp, V'Unchecked_Access);
|
|
|
|
case Interp.Token.Kind is
|
|
when End_Token =>
|
|
Ada.Text_IO.Put_Line ("ERROR: PREMATURE LIST END");
|
|
raise Syntax_Error;
|
|
|
|
when Left_Parenthesis_Token =>
|
|
Push_Frame (Interp, Opcode_Read_List, Nil_Pointer);
|
|
|
|
when Right_Parenthesis_Token =>
|
|
V := Get_Frame_Result(Interp.Stack);
|
|
if V /= Nil_Pointer then
|
|
V := Reverse_Cons(V);
|
|
end if;
|
|
Pop_Frame (Interp);
|
|
Chain_Frame_Result (Interp, Interp.Stack, V);
|
|
|
|
when Period_Token =>
|
|
V := Get_Frame_Result(Interp.Stack);
|
|
if V = Nil_Pointer then
|
|
-- . immediately after (
|
|
raise Syntax_Error;
|
|
else
|
|
Set_Frame_Opcode (Interp.Stack, Opcode_Read_List_Cdr);
|
|
end if;
|
|
|
|
when Single_Quote_Token =>
|
|
Push_Frame (Interp, Opcode_Close_Quote, Nil_Pointer);
|
|
Push_Frame (Interp, Opcode_Read_Object, Nil_Pointer);
|
|
|
|
when Integer_Token =>
|
|
-- TODO: bignum
|
|
V := String_To_Integer_Pointer(Interp.Token.Value.Ptr.all(1..Interp.Token.Value.Last));
|
|
Chain_Frame_Result (Interp, Interp.Stack, V);
|
|
|
|
when Character_Token =>
|
|
pragma Assert (Interp.Token.Value.Last = 1);
|
|
V := Character_To_Pointer(Interp.Token.Value.Ptr.all(1));
|
|
Chain_Frame_Result (Interp, Interp.Stack, V);
|
|
|
|
when String_Token =>
|
|
V := Make_String(Interp.Self, Interp.Token.Value.Ptr.all(1..Interp.Token.Value.Last));
|
|
Chain_Frame_Result (Interp, Interp.Stack, V);
|
|
|
|
when Identifier_Token =>
|
|
V := Make_Symbol(Interp.Self, Interp.Token.Value.Ptr.all(1..Interp.Token.Value.Last));
|
|
Chain_Frame_Result (Interp, Interp.Stack, V);
|
|
|
|
when True_Token =>
|
|
Chain_Frame_Result (Interp, Interp.Stack, True_Pointer);
|
|
|
|
when False_Token =>
|
|
Chain_Frame_Result (Interp, Interp.Stack, False_Pointer);
|
|
|
|
when others =>
|
|
-- TODO: set various error info
|
|
raise Syntax_Error;
|
|
end case;
|
|
|
|
--Pop_Tops (Interp, 1);
|
|
end Read_List;
|
|
|
|
procedure Read_List_Cdr is
|
|
pragma Inline (Read_List_Cdr);
|
|
V: aliased Object_Pointer;
|
|
begin
|
|
-- This procedure reads the first token after a period has been read.
|
|
-- It transfers the control over to Read_List_End once it has read
|
|
-- and processed the token. It chains the value made of the token
|
|
-- to the front of the frame's return value list expecting Read_List_End
|
|
-- to handle the head item specially.
|
|
Fetch_Token;
|
|
|
|
--Push_Top (Interp, V'Unchecked_Access);
|
|
|
|
case Interp.Token.Kind is
|
|
when End_Token =>
|
|
Ada.Text_IO.Put_Line ("ERROR: PREMATURE LIST END");
|
|
raise Syntax_Error;
|
|
|
|
when Left_Parenthesis_Token =>
|
|
Set_Frame_Opcode (Interp.Stack, Opcode_Read_List_End);
|
|
Push_Frame (Interp, Opcode_Read_List, Nil_Pointer);
|
|
|
|
when Single_Quote_Token =>
|
|
Ada.Text_IO.Put_Line ("ERROR: CDR QUOT LIST END");
|
|
Set_Frame_Opcode (Interp.Stack, Opcode_Read_List_End);
|
|
Push_Frame (Interp, Opcode_Close_Quote, Nil_Pointer);
|
|
Push_Frame (Interp, Opcode_Read_Object, Nil_Pointer);
|
|
|
|
when Integer_Token =>
|
|
-- TODO: bignum
|
|
V := String_To_Integer_Pointer(Interp.Token.Value.Ptr.all(1..Interp.Token.Value.Last));
|
|
Set_Frame_Opcode (Interp.Stack, Opcode_Read_List_End);
|
|
Chain_Frame_Result (Interp, Interp.Stack, V);
|
|
|
|
when Character_Token =>
|
|
pragma Assert (Interp.Token.Value.Last = 1);
|
|
V := Character_To_Pointer(Interp.Token.Value.Ptr.all(1));
|
|
Set_Frame_Opcode (Interp.Stack, Opcode_Read_List_End);
|
|
Chain_Frame_Result (Interp, Interp.Stack, V);
|
|
|
|
when String_Token =>
|
|
V := Make_String (Interp.Self, Interp.Token.Value.Ptr.all(1..Interp.Token.Value.Last));
|
|
Set_Frame_Opcode (Interp.Stack, Opcode_Read_List_End);
|
|
Chain_Frame_Result (Interp, Interp.Stack, V);
|
|
|
|
when Identifier_Token =>
|
|
V := Make_Symbol (Interp.Self, Interp.Token.Value.Ptr.all(1..Interp.Token.Value.Last));
|
|
Set_Frame_Opcode (Interp.Stack, Opcode_Read_List_End);
|
|
Chain_Frame_Result (Interp, Interp.Stack, V);
|
|
|
|
when True_Token =>
|
|
Set_Frame_Opcode (Interp.Stack, Opcode_Read_List_End);
|
|
Chain_Frame_Result (Interp, Interp.Stack, True_Pointer);
|
|
|
|
when False_Token =>
|
|
Set_Frame_Opcode (Interp.Stack, Opcode_Read_List_End);
|
|
Chain_Frame_Result (Interp, Interp.Stack, False_Pointer);
|
|
|
|
when others =>
|
|
-- TODO: set various error info
|
|
raise Syntax_Error;
|
|
end case;
|
|
|
|
--Pop_Tops (Interp, 1);
|
|
end Read_List_Cdr;
|
|
|
|
procedure Read_List_End is
|
|
pragma Inline (Read_List_End);
|
|
V: aliased Object_Pointer;
|
|
begin
|
|
Fetch_Token;
|
|
|
|
--Push_Top (Interp, V'Unchecked_Access);
|
|
|
|
case Interp.Token.Kind is
|
|
when Right_Parenthesis_Token =>
|
|
V := Get_Frame_Result(Interp.Stack);
|
|
pragma Assert (V /= Nil_Pointer);
|
|
-- The first item in the chain is actually Cdr of the last cell.
|
|
V := Reverse_Cons(Get_Cdr(V), Get_Car(V));
|
|
Pop_Frame (Interp);
|
|
Chain_Frame_Result (Interp, Interp.Stack, V);
|
|
when others =>
|
|
Ada.Text_IO.Put_Line ("Right parenthesis expected");
|
|
raise Syntax_Error;
|
|
end case;
|
|
|
|
--Pop_Tops (Interp, 1);
|
|
end Read_List_End;
|
|
|
|
procedure Close_List is
|
|
pragma Inline (Close_List);
|
|
V: aliased Object_Pointer;
|
|
begin
|
|
--Push_Top (Interp, V'Unchecked_Access);
|
|
|
|
V := Get_Frame_Result(Interp.Stack);
|
|
pragma Assert (Get_Cdr(V) = Nil_Pointer);
|
|
Pop_Frame (Interp); -- Done with the current frame
|
|
Chain_Frame_Result (Interp, Interp.Stack, Get_Car(V));
|
|
|
|
--Pop_Tops (Interp, 1);
|
|
end Close_List;
|
|
|
|
procedure Close_Quote is
|
|
pragma Inline (Close_Quote);
|
|
V: aliased Object_Pointer;
|
|
begin
|
|
--Push_Top (Interp, V'Unchecked_Access);
|
|
|
|
Chain_Frame_Result (Interp, Interp.Stack, Interp.Symbol.Quote);
|
|
V := Get_Frame_Result(Interp.Stack);
|
|
Pop_Frame (Interp); -- Done with the current frame
|
|
Chain_Frame_Result (Interp, Interp.Stack, V);
|
|
|
|
--Pop_Tops (Interp, 1);
|
|
end Close_Quote;
|
|
|
|
procedure Read_Object is
|
|
pragma Inline (Read_Object);
|
|
V: aliased Object_Pointer;
|
|
begin
|
|
Fetch_Token;
|
|
|
|
--Push_Top (Interp, V'Unchecked_Access);
|
|
|
|
case Interp.Token.Kind is
|
|
when End_Token =>
|
|
Ada.Text_IO.Put_Line ("INFO: NO MORE TOKEN ");
|
|
raise Stream_End_Error;
|
|
|
|
when Left_Parenthesis_Token =>
|
|
Set_Frame_Opcode (Interp.Stack, Opcode_Close_List);
|
|
Push_Frame (Interp, Opcode_Read_List, Nil_Pointer);
|
|
|
|
when Single_Quote_Token =>
|
|
Set_Frame_Opcode (Interp.Stack, Opcode_Close_Quote);
|
|
Push_Frame (Interp, Opcode_Read_Object, Nil_Pointer);
|
|
|
|
when Integer_Token =>
|
|
-- TODO: bignum
|
|
V := String_To_Integer_Pointer(Interp.Token.Value.Ptr.all(1..Interp.Token.Value.Last));
|
|
Pop_Frame (Interp); -- Done with the current frame
|
|
Chain_Frame_Result (Interp, Interp.Stack, V);
|
|
|
|
when Character_Token =>
|
|
pragma Assert (Interp.Token.Value.Last = 1);
|
|
V := Character_To_Pointer(Interp.Token.Value.Ptr.all(1));
|
|
Pop_Frame (Interp); -- Done with the current frame
|
|
Chain_Frame_Result (Interp, Interp.Stack, V);
|
|
|
|
when String_Token =>
|
|
V := Make_String (Interp.Self, Interp.Token.Value.Ptr.all(1..Interp.Token.Value.Last));
|
|
Pop_Frame (Interp); -- Done with the current frame
|
|
Chain_Frame_Result (Interp, Interp.Stack, V);
|
|
|
|
when Identifier_Token =>
|
|
V := Make_Symbol (Interp.Self, Interp.Token.Value.Ptr.all(1..Interp.Token.Value.Last));
|
|
Pop_Frame (Interp); -- Done with the current frame
|
|
Chain_Frame_Result (Interp, Interp.Stack, V);
|
|
|
|
when True_Token =>
|
|
Pop_Frame (Interp); -- Done with the current frame
|
|
Chain_Frame_Result (Interp, Interp.Stack, True_Pointer);
|
|
|
|
when False_Token =>
|
|
Pop_Frame (Interp); -- Done with the current frame
|
|
Chain_Frame_Result (Interp, Interp.Stack, False_Pointer);
|
|
|
|
|
|
when others =>
|
|
-- TODO: set various error info
|
|
Ada.Text_IO.Put_Line ("INFO: UNKNOWN TOKEN " & Token_Kind'Image(Interp.Token.Kind));
|
|
raise Syntax_Error;
|
|
end case;
|
|
|
|
--Pop_Tops (Interp, 1);
|
|
end Read_Object;
|
|
|
|
begin
|
|
|
|
-- Stack frames looks like this upon initialization
|
|
--
|
|
-- | Opcode | Operand | Result
|
|
-- -----------------------------------------------------------------
|
|
-- top | Opcode_Evaluate_Object | Source | Nil
|
|
-- bottom | Opcode_Exit | Nil | Nil
|
|
--
|
|
-- For a source (+ 1 2), it should look like this.
|
|
-- -----------------------------------------------------------------
|
|
-- top | Opcode_Evaluate_Object | Source | Nil
|
|
-- bottom | Opcode_Exit | Nil | Nil
|
|
--
|
|
-- The operand changes to the cdr of the source.
|
|
-- The symbol '+' is pushed to the stack with Opcode_Evaluate_Object.
|
|
-- -----------------------------------------------------------------
|
|
-- top | Opcode_Evaluate_Object | + | Nil
|
|
-- | Opcode_Evaluate_Object | (1 2) | Nil
|
|
-- bottom | Opcode_Exit | Nil | Nil
|
|
--
|
|
-- After the evaluation of the symbol, the pushed frame is removed
|
|
-- and the result is set to the return field.
|
|
-- -----------------------------------------------------------------
|
|
-- top | Opcode_Evaluate_Object | (1 2) | (#Proc+)
|
|
-- bottom | Opcode_Exit | Nil | Nil
|
|
--
|
|
-- The same action is taken to evaluate the literal 1.
|
|
-- -----------------------------------------------------------------
|
|
-- top | Opcode_Evaluate_Object | 1 | Nil
|
|
-- | Opcode_Evaluate_Object | (2) | (#Proc+)
|
|
-- bottom | Opcode_Exit | Nil | Nil
|
|
--
|
|
-- The result of the valuation is reverse-chained to the return field.
|
|
-- -----------------------------------------------------------------
|
|
-- top | Opcode_Evaluate_Object | (2) | (1 #Proc+)
|
|
-- bottom | Opcode_Exit | Nil | Nil
|
|
--
|
|
-- The same action is taken to evaluate the literal 2.
|
|
-- -----------------------------------------------------------------
|
|
-- top | Opcode_Evaluate_Object | 2 | Nil
|
|
-- | Opcode_Evaluate_Object | Mark | (1 #Proc+)
|
|
-- bottom | Opcode_Exit | Nil | Nil
|
|
--
|
|
-- The result of the valuation is reverse-chained to the return field.
|
|
-- -----------------------------------------------------------------
|
|
-- top | Opcode_Evaluate_Object | Mark | (2 1 #Proc+)
|
|
-- bottom | Opcode_Exit | Nil | Nil
|
|
--
|
|
-- Once evluation of each cons cell is complete, switch the top frame
|
|
-- to 'Apply' reversing the result field into the operand field and
|
|
-- nullifying the result field afterwards.
|
|
-- -----------------------------------------------------------------
|
|
-- top | Apply | (#Proc+ 1 2) | Nil
|
|
-- bottom | Opcode_Exit | Nil | Nil
|
|
--
|
|
-- The apply operation produces the final result and sets it to the
|
|
-- parent frame while removing the apply frame.
|
|
-- -----------------------------------------------------------------
|
|
-- top/bottom| Opcode_Exit | Nil | (3)
|
|
|
|
-- The caller must push some frames before calling this procedure
|
|
pragma Assert (Interp.Stack /= Nil_Pointer);
|
|
|
|
-- The caller must ensure there are no temporary object pointers.
|
|
pragma Assert (Interp.Top.Last < Interp.Top.Data'First);
|
|
|
|
loop
|
|
case Get_Frame_Opcode(Interp.Stack) is
|
|
when Opcode_Exit =>
|
|
exit;
|
|
|
|
when Opcode_Evaluate_Result =>
|
|
Evaluate_Result;
|
|
|
|
when Opcode_Evaluate_Object =>
|
|
Evaluate;
|
|
|
|
when Opcode_Finish_And_Syntax =>
|
|
Finish_And_Syntax; -- Conditional
|
|
|
|
--when Opcode_Finish_Case_Syntax =>
|
|
--when Opcode_Finish_Cond_Syntax =>
|
|
|
|
when Opcode_Finish_Define_Symbol =>
|
|
Finish_Define_Symbol;
|
|
|
|
when Opcode_Finish_If_Syntax =>
|
|
Finish_If_Syntax; -- Conditional
|
|
|
|
when Opcode_Grouped_Call =>
|
|
Do_Grouped_Call;
|
|
when Opcode_Grouped_Call_Finish =>
|
|
Do_Grouped_Call_Finish;
|
|
|
|
when Opcode_Let_Binding =>
|
|
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 =>
|
|
Do_Let_Finish;
|
|
|
|
when Opcode_Procedure_Call =>
|
|
Do_Procedure_Call;
|
|
|
|
when Opcode_Set_Finish =>
|
|
Do_Set_Finish; -- Assignment
|
|
|
|
when Opcode_Finish_Or_Syntax =>
|
|
Finish_Or_Syntax; -- Conditional
|
|
|
|
when Opcode_Apply =>
|
|
Apply;
|
|
|
|
when Opcode_Read_Object =>
|
|
Read_Object;
|
|
|
|
when Opcode_Read_List =>
|
|
Read_List;
|
|
|
|
when Opcode_Read_List_Cdr =>
|
|
Read_List_Cdr;
|
|
|
|
when Opcode_Read_List_End =>
|
|
Read_List_End;
|
|
|
|
when Opcode_Close_List =>
|
|
Close_List;
|
|
|
|
when Opcode_Close_Quote =>
|
|
Close_Quote;
|
|
|
|
end case;
|
|
end loop;
|
|
|
|
exception
|
|
when Stream_End_Error =>
|
|
Ada.Text_IO.Put_Line ("INFO: NO MORE TOKEN .............");
|
|
raise;
|
|
|
|
when others =>
|
|
Ada.Text_IO.Put_Line ("EXCEPTION OCCURRED");
|
|
-- TODO: restore stack frame???
|
|
-- TODO: restore envirronemtn frame???
|
|
raise;
|
|
end Execute;
|