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written more code for reading expressions

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hyung-hwan 2014-01-07 17:02:12 +00:00
parent 78fb4223e9
commit 73c29ce53b
3 changed files with 420 additions and 227 deletions
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6
cmd/scheme.adb
View File

@ -43,13 +43,17 @@ begin
--S.Set_Input_Stream (SI, String_Stream); --S.Set_Input_Stream (SI, String_Stream);
--S.Set_Output_Stream (SI, Stream); -- specify main output stream. --S.Set_Output_Stream (SI, Stream); -- specify main output stream.
S.Read (SI, I); --S.Read (SI, I);
S.Make_Test_Object (SI, I); S.Make_Test_Object (SI, I);
S.Evaluate (SI, I, O); S.Evaluate (SI, I, O);
S.Print (SI, I); S.Print (SI, I);
Ada.Text_IO.Put_Line ("-------------------------------------------"); Ada.Text_IO.Put_Line ("-------------------------------------------");
S.Print (SI, O); S.Print (SI, O);
Ada.Text_IO.Put_Line ("-------------------------------------------");
S.Run_Loop (SI, I);
S.Print (SI, I);
S.Close (SI); S.Close (SI);
declare declare

634
lib/h2-scheme.adb
View File

@ -33,6 +33,7 @@ package body H2.Scheme is
Evaluation_Error: exception; Evaluation_Error: exception;
Internal_Error: exception; Internal_Error: exception;
IO_Error: exception; IO_Error: exception;
Stream_End_Error: exception;
----------------------------------------------------------------------------- -----------------------------------------------------------------------------
-- INTERNALLY-USED TYPES -- INTERNALLY-USED TYPES
@ -47,14 +48,16 @@ package body H2.Scheme is
subtype Moved_Object_Record is Object_Record (Moved_Object, 0); subtype Moved_Object_Record is Object_Record (Moved_Object, 0);
subtype Opcode_Type is Object_Integer range 0 .. 6; subtype Opcode_Type is Object_Integer range 0 .. 8;
Opcode_Exit: constant Opcode_Type := Opcode_Type'(0); Opcode_Exit: constant Opcode_Type := Opcode_Type'(0);
Opcode_Evaluate_Object: constant Opcode_Type := Opcode_Type'(1); Opcode_Evaluate_Object: constant Opcode_Type := Opcode_Type'(1);
Opcode_Evaluate_Group: constant Opcode_Type := Opcode_Type'(2); Opcode_Evaluate_Group: constant Opcode_Type := Opcode_Type'(2); -- (begin ...) and closure apply
Opcode_Evaluate_Syntax: constant Opcode_Type := Opcode_Type'(3); Opcode_Evaluate_Syntax: constant Opcode_Type := Opcode_Type'(3);
Opcode_Evaluate_Procedure: constant Opcode_Type := Opcode_Type'(4); Opcode_Evaluate_Procedure: constant Opcode_Type := Opcode_Type'(4);
Opcode_Apply: constant Opcode_Type := Opcode_Type'(5); Opcode_Apply: constant Opcode_Type := Opcode_Type'(5);
Opcode_Read_Object: constant Opcode_Type := Opcode_Type'(6); Opcode_Read_Object: constant Opcode_Type := Opcode_Type'(6);
Opcode_Read_List: constant Opcode_Type := Opcode_Type'(7);
Opcode_Close_List: constant Opcode_Type := Opcode_Type'(8);
----------------------------------------------------------------------------- -----------------------------------------------------------------------------
-- COMMON OBJECTS -- COMMON OBJECTS
@ -891,7 +894,7 @@ Text_IO.Put_Line (">>> [GC DONE]");
----------------------------------------------------------------------------- -----------------------------------------------------------------------------
function Make_String (Interp: access Interpreter_Record; function Make_String (Interp: access Interpreter_Record;
Source: in Object_String) return Object_Pointer is Source: in Object_String) return Object_Pointer is
Result: Object_Pointer; Result: Object_Pointer;
begin begin
Result := Allocate_Character_Object (Interp, Source); Result := Allocate_Character_Object (Interp, Source);
@ -945,7 +948,6 @@ Print_Object_Pointer ("Make_String Result - " & Source, Result);
-- Make it GC-aweare. Protect Ptr -- Make it GC-aweare. Protect Ptr
-- Link the symbol to the symbol table. -- Link the symbol to the symbol table.
Interp.Symbol_Table := Make_Cons (Interp.Self, Ptr, Interp.Symbol_Table); Interp.Symbol_Table := Make_Cons (Interp.Self, Ptr, Interp.Symbol_Table);
--Print_Object_Pointer ("Make_Symbol Result - " & Source, Result);
return Ptr; return Ptr;
end Make_Symbol; end Make_Symbol;
@ -1181,13 +1183,13 @@ Put_String (To_Thin_String_Pointer (Result));
return Frame.Pointer_Slot(Frame_Return_Index); return Frame.Pointer_Slot(Frame_Return_Index);
end Get_Frame_Return; end Get_Frame_Return;
procedure Set_Frame_Return (Frame: in out Object_Pointer; --procedure Set_Frame_Return (Frame: in out Object_Pointer;
Value: in Object_Pointer) is -- Value: in Object_Pointer) is
pragma Inline (Set_Frame_Return); -- pragma Inline (Set_Frame_Return);
pragma Assert (Is_Frame(Frame)); -- pragma Assert (Is_Frame(Frame));
begin --begin
Frame.Pointer_Slot(Frame_Return_Index) := Value; -- Frame.Pointer_Slot(Frame_Return_Index) := Value;
end Set_Frame_Return; --end Set_Frame_Return;
procedure Chain_Frame_Return (Interp: in out Interpreter_Record; procedure Chain_Frame_Return (Interp: in out Interpreter_Record;
Frame: in out Object_Pointer; Frame: in out Object_Pointer;
@ -1195,12 +1197,12 @@ Put_String (To_Thin_String_Pointer (Result));
pragma Inline (Chain_Frame_Return); pragma Inline (Chain_Frame_Return);
pragma Assert (Is_Frame(Frame)); pragma Assert (Is_Frame(Frame));
Cons: Object_Pointer renames Frame.Pointer_Slot(Frame_Return_Index); Ret_Head: Object_Pointer renames Frame.Pointer_Slot(Frame_Return_Index);
begin begin
-- TODO: make it GC-aware -- TODO: make it GC-aware
-- Add a new cons cell to the front -- Add a new cons cell to the front
Cons := Make_Cons (Interp.Self, Value, Cons); Ret_Head := Make_Cons (Interp.Self, Value, Ret_Head);
end Chain_Frame_Return; end Chain_Frame_Return;
procedure Clear_Frame_Return (Frame: in out Object_Pointer) is procedure Clear_Frame_Return (Frame: in out Object_Pointer) is
@ -1554,153 +1556,6 @@ Text_IO.Put_Line (To_Object_String(IO_Character_Record'Max_Size_In_Storage_Eleme
-- --
--end Set_Output_Stream; --end Set_Output_Stream;
procedure Read (Interp: in out Interpreter_Record;
Result: out Object_Pointer) is
procedure Fetch_Character is
begin
-- TODO: calculate Interp.Input.Row, Interp.Input.Column
if Interp.Input.Pos >= Interp.Input.Last then
if Interp.Input.Flags /= 0 then
-- An error has occurred or EOF has been reached previously.
-- Note calling this procedure after EOF results in an error.
Interp.Input.Iochar := (Error_Character, Object_Character'First);
--return;
raise IO_Error;
end if;
Interp.Input.Pos := Interp.Input.Data'First - 1;
begin
Read (Interp.Input.Stream.all, Interp.Input.Data, Interp.Input.Last);
exception
when others =>
-- The callee can raise an exception upon errors.
-- If an exception is raised, data read into the buffer
-- is also ignored.
Interp.Input.Flags := Interp.Input.Flags and IO_Error_Occurred;
Interp.Input.Iochar := (Error_Character, Object_Character'First);
--return;
raise IO_Error;
end;
if Interp.Input.Last < Interp.Input.Data'First then
-- The callee must read 0 bytes on EOF
Interp.Input.Flags := Interp.Input.Flags and IO_End_Reached;
Interp.Input.Iochar := (End_Character, Object_Character'First);
return;
end if;
end if;
Interp.Input.Pos := Interp.Input.Pos + 1;
Interp.Input.Iochar := (Normal_Character, Interp.Input.Data(Interp.Input.Pos));
end Fetch_Character;
function Is_White_Space (X: in Object_Character) return Standard.Boolean is
begin
return X = ' ' or else
X = Object_Character'Val(Standard.Character'Pos(Standard.ASCII.HT)) or else
X = Object_Character'Val(Standard.Character'Pos(Standard.ASCII.VT)) or else
X = Object_Character'Val(Standard.Character'Pos(Standard.ASCII.CR)) or else
X = Object_Character'Val(Standard.Character'Pos(Standard.ASCII.LF)) or else
X = Object_Character'Val(Standard.Character'Pos(Standard.ASCII.FF));
end Is_White_Space;
procedure Skip_Spaces is
C: IO_Character_Record renames Interp.Input.Iochar;
begin
loop
exit when C.Kind /= Normal_Character;
-- Normal character
if Is_White_Space(C.Value) then
Fetch_Character;
elsif C.Value = ';' then
-- Comment.
loop
Fetch_Character;
exit when C.Kind = End_Character; -- EOF before LF
if C.Kind = Normal_Character and then
C.Value = Object_Character'Val(Standard.Character'Pos(Standard.ASCII.LF)) then
Fetch_Character; -- Consume LF
exit;
end if;
end loop;
else
exit;
end if;
end loop;
end Skip_Spaces;
procedure Fetch_Token is
C: IO_Character_Record renames Interp.Input.Iochar;
begin
Skip_Spaces;
if C.Kind /= Normal_Character then
Token.Set (Interp, End_Token, "");
return;
end if;
case C.Value is
when '(' =>
Token.Set (Interp, Left_Parenthesis_Token, "(");
Fetch_Character;
when ')' =>
Token.Set (Interp, Right_Parenthesis_Token, ")");
Fetch_Character;
when ''' =>
Token.Set (Interp, Single_Quote_Token, "'");
Fetch_Character;
when '"' =>
Token.Set (Interp, String_Token, "'");
Fetch_Character;
-- TODO:
when '#' =>
Fetch_Character;
-- TODO: t, false, etc
when others =>
Token.Set (Interp, Identifier_Token, "");
loop
Token.Append_Character (Interp, C.Value);
Fetch_Character;
--exit when not Is_Ident_Char(C.Value);
if C.Value = '(' or else C.Value = ')' or else
C.Value = ''' or else C.Value = '"' or else
C.Value = '#' or else C.Value = ';' or else
Is_White_Space(C.Value) then
exit;
end if;
end loop;
end case;
Text_IO.Put_Line (">>>>>>>>>>>>>>>>>>>>>>> Token: " & Interp.Token.Value.Ptr(1..Interp.Token.Value.Last));
end Fetch_Token;
procedure Read_Atom (Atom: out Object_Pointer) is
begin
null;
end Read_Atom;
Stack: Object_Pointer;
Opcode: Object_Integer;
Operand: Object_Pointer;
begin
Fetch_Character;
loop
Fetch_Token;
exit when Interp.Token.Kind = End_Token;
end loop;
exception
when IO_Error =>
Text_IO.Put_Line ("****************************** INPUT ERROR...");
end Read;
procedure Print (Interp: in out Interpreter_Record; procedure Print (Interp: in out Interpreter_Record;
Source: in Object_Pointer) is Source: in Object_Pointer) is
@ -1945,6 +1800,7 @@ procedure Make_Test_Object (Interp: in out Interpreter_Record; Result: out Objec
P: Object_Pointer; P: Object_Pointer;
B: Object_Pointer; B: Object_Pointer;
L: Object_Pointer; L: Object_Pointer;
Resultx: Object_Pointer;
begin begin
--(define x 10) --(define x 10)
--Result := Make_Cons ( --Result := Make_Cons (
@ -2007,16 +1863,24 @@ begin
) )
); );
Z := Make_Cons ( Z := Make_Cons (
Interp.Self, Interp.Self,
Make_Symbol (Interp.Self, "begin"), Make_Symbol (Interp.Self, "begin"),
Y Make_COns (Interp.Self, Y, Nil_Pointer)
);
B := Make_Cons (
Interp.Self,
Make_Symbol (Interp.Self, "begin"),
Make_Cons (Interp.Self, Z, Nil_Pointer)
); );
Result := Make_Cons ( Result := Make_Cons (
Interp.Self, Interp.Self,
Make_Symbol (Interp.Self, "begin"), Make_Symbol (Interp.Self, "+"),
Make_Cons (Interp.Self, Z, Nil_Pointer) Make_Cons (Interp.Self, Integer_To_Pointer(88), Make_Cons (Interp.Self, B, Nil_Pointer))
); );
-- (lambda (x y) (+ x y)) -- (lambda (x y) (+ x y))
@ -2090,35 +1954,36 @@ end Make_Test_Object;
return Integer_To_Pointer(Opcode); return Integer_To_Pointer(Opcode);
end Opcode_To_Pointer; end Opcode_To_Pointer;
procedure Evaluate (Interp: in out Interpreter_Record; procedure Push_Frame (Interp: in out Interpreter_Record;
Source: in Object_Pointer; Opcode: in Opcode_Type;
Result: out Object_Pointer) is Operand: in Object_Pointer) is
pragma Inline (Push_Frame);
begin
Interp.Stack := Make_Frame (Interp.Self, Interp.Stack, Opcode_To_Pointer(Opcode), Operand, Interp.Environment);
end Push_Frame;
procedure Push_Frame (Opcode: in Opcode_Type; --procedure Pop_Frame (Interp.Stack: out Object_Pointer;
Operand: in Object_Pointer) is -- Opcode: out Opcode_Type;
pragma Inline (Push_Frame); -- Operand: out Object_Pointer) is
begin -- pragma Inline (Pop_Frame);
Interp.Stack := Make_Frame (Interp.Self, Interp.Stack, Opcode_To_Pointer(Opcode), Operand, Interp.Environment); --begin
end Push_Frame; -- pragma Assert (Interp.Stack /= Nil_Pointer);
-- Opcode := Pointer_To_Opcode(Interp.Stack.Pointer_Slot(Frame_Opcode_Index));
-- Operand := Interp.Stack.Pointer_Slot(Frame_Operand_Index);
-- Interp.Stack := Interp.Stack.Pointer_Slot(Frame_Stack_Index); -- pop
--end Pop_Frame;
--procedure Pop_Frame (Interp.Stack: out Object_Pointer; procedure Pop_Frame (Interp: in out Interpreter_Record) is
-- Opcode: out Opcode_Type; pragma Inline (Pop_Frame);
-- Operand: out Object_Pointer) is begin
-- pragma Inline (Pop_Frame); pragma Assert (Interp.Stack /= Nil_Pointer);
--begin Interp.Environment := Interp.Stack.Pointer_Slot(Frame_Environment_Index); -- restore environment
-- pragma Assert (Interp.Stack /= Nil_Pointer); Interp.Stack := Interp.Stack.Pointer_Slot(Frame_Stack_Index); -- pop
-- Opcode := Pointer_To_Opcode(Interp.Stack.Pointer_Slot(Frame_Opcode_Index)); end Pop_Frame;
-- Operand := Interp.Stack.Pointer_Slot(Frame_Operand_Index);
-- Interp.Stack := Interp.Stack.Pointer_Slot(Frame_Stack_Index); -- pop
--end Pop_Frame;
procedure Pop_Frame is procedure Execute (Interp: in out Interpreter_Record) is
pragma Inline (Pop_Frame);
begin LC: IO_Character_Record renames Interp.Input.Iochar;
pragma Assert (Interp.Stack /= Nil_Pointer);
Interp.Environment := Interp.Stack.Pointer_Slot(Frame_Environment_Index); -- restore environment
Interp.Stack := Interp.Stack.Pointer_Slot(Frame_Stack_Index); -- pop
end Pop_Frame;
procedure Evaluate_Group is procedure Evaluate_Group is
pragma Inline (Evaluate_Group); pragma Inline (Evaluate_Group);
@ -2144,6 +2009,10 @@ end Make_Test_Object;
Text_IO.Put_Line ("$$$$..................FUCKING CDR. FOR GROUP....................$$$$"); Text_IO.Put_Line ("$$$$..................FUCKING CDR. FOR GROUP....................$$$$");
-- raise Syntax_Error; -- raise Syntax_Error;
end if; end if;
-- Change the operand to a mark object so that the call to this
-- procedure after the evaluation of the last car goes to the
-- Mark_Object case.
Set_Frame_Operand (Interp.Stack, Interp.Mark); Set_Frame_Operand (Interp.Stack, Interp.Mark);
end if; end if;
@ -2151,12 +2020,17 @@ end Make_Test_Object;
Clear_Frame_Return (Interp.Stack); Clear_Frame_Return (Interp.Stack);
-- Arrange to evaluate the current expression -- Arrange to evaluate the current expression
Push_Frame (Opcode_Evaluate_Object, Car); Push_Frame (Interp, Opcode_Evaluate_Object, Car);
when Mark_Object => when Mark_Object =>
Operand := Get_Frame_Return (Interp.Stack); Operand := Get_Frame_Return (Interp.Stack);
Pop_Frame; -- Done; Pop_Frame (Interp); -- Done
Set_Frame_Return (Interp.Stack, Operand);
-- There must be only 1 return value chained in the Group frame.
pragma Assert (Get_Cdr(Operand) = Nil_Pointer);
-- Transfer the only return value to the upper chain
Chain_Frame_Return (Interp, Interp.Stack, Get_Car(Operand));
when others => when others =>
raise Internal_Error; raise Internal_Error;
@ -2186,6 +2060,7 @@ end Make_Test_Object;
if Car = null then if Car = null then
-- unbound -- unbound
Text_IO.Put_Line ("Unbound symbol...."); Text_IO.Put_Line ("Unbound symbol....");
Print (Interp, Operand);
raise Evaluation_Error; raise Evaluation_Error;
else else
-- symbol found in the environment -- symbol found in the environment
@ -2210,13 +2085,12 @@ end Make_Test_Object;
-- (begin . 10) -- (begin . 10)
Text_IO.Put_LINE ("FUCKNING CDR FOR BEGIN"); Text_IO.Put_LINE ("FUCKNING CDR FOR BEGIN");
raise Syntax_Error; raise Syntax_Error;
--Pop_Frame; -- Done --Pop_Frame (Interp); -- Done
else else
Set_Frame_Opcode (Interp.Stack, Opcode_Evaluate_Group); Set_Frame_Opcode (Interp.Stack, Opcode_Evaluate_Group);
Set_Frame_Operand (Interp.Stack, Operand); Set_Frame_Operand (Interp.Stack, Operand);
if (Interp.Trait.Trait_Bits and No_Optimization) = 0 then if (Interp.Trait.Trait_Bits and No_Optimization) = 0 then
-- I call Evaluate_Group for optimization here. -- I call Evaluate_Group for optimization here.
Evaluate_Group; -- for optimization only. not really needed. Evaluate_Group; -- for optimization only. not really needed.
@ -2238,26 +2112,26 @@ end Make_Test_Object;
-- (lambda . 10) -- (lambda . 10)
Text_IO.Put_LINE ("FUCKNING CDR FOR BEGIN"); Text_IO.Put_LINE ("FUCKNING CDR FOR BEGIN");
raise Syntax_Error; raise Syntax_Error;
--Pop_Frame; -- Done --Pop_Frame (Interp); -- Done
else else
if not Is_Cons(Get_Car(Operand)) then if not Is_Cons(Get_Car(Operand)) then
Text_IO.Put_Line ("INVALID PARRAMETER LIST"); Text_IO.Put_Line ("INVALID PARRAMETER LIST");
raise Syntax_Error; raise Syntax_Error;
--Pop_Frame; -- Done --Pop_Frame (Interp); -- Done
end if; end if;
--Print (Interp, Get_Cdr(Operand)); --Print (Interp, Get_Cdr(Operand));
if not Is_Cons(Get_Cdr(Operand)) then if not Is_Cons(Get_Cdr(Operand)) then
Text_IO.Put_Line ("NO BODY"); Text_IO.Put_Line ("NO BODY");
raise Syntax_Error; raise Syntax_Error;
--Pop_Frame; -- Done --Pop_Frame (Interp); -- Done
end if; end if;
declare declare
Closure: Object_Pointer; Closure: Object_Pointer;
begin begin
Closure := Make_Closure (Interp.Self, Operand, Interp.Environment); Closure := Make_Closure (Interp.Self, Operand, Interp.Environment);
Pop_Frame; -- Done Pop_Frame (Interp); -- Done
Chain_Frame_Return (Interp, Interp.Stack, Closure); Chain_Frame_Return (Interp, Interp.Stack, Closure);
end; end;
end if; end if;
@ -2310,7 +2184,7 @@ end Make_Test_Object;
-- Arrange to evaluate the car object -- Arrange to evaluate the car object
if (Interp.Trait.Trait_Bits and No_Optimization) = 0 then if (Interp.Trait.Trait_Bits and No_Optimization) = 0 then
Push_Frame (Opcode_Evaluate_Object, Car); Push_Frame (Interp, Opcode_Evaluate_Object, Car);
goto Start_Over; -- for optimization only. not really needed. goto Start_Over; -- for optimization only. not really needed.
end if; end if;
end if; end if;
@ -2327,8 +2201,8 @@ end Make_Test_Object;
-- This should be faster than Popping the current frame and pushing -- This should be faster than Popping the current frame and pushing
-- a new frame. -- a new frame.
-- Envir := Get_Frame_Environment(Interp.Stack); -- Envir := Get_Frame_Environment(Interp.Stack);
-- Pop_Frame (Interp.Stack); -- done -- Pop_Frame (Interp); -- done
-- Push_Frame (Interp.Stack, Opcode_Apply, Operand, Envir); -- Push_Frame (Interp, Opcode_Apply, Operand, Envir);
Clear_Frame_Return (Interp.Stack); Clear_Frame_Return (Interp.Stack);
Set_Frame_Opcode (Interp.Stack, Opcode_Apply); Set_Frame_Opcode (Interp.Stack, Opcode_Apply);
Set_Frame_Operand (Interp.Stack, Operand); Set_Frame_Operand (Interp.Stack, Operand);
@ -2340,13 +2214,12 @@ end Make_Test_Object;
return; return;
<<Literal>> <<Literal>>
Pop_Frame; -- done Pop_Frame (Interp); -- done
Text_IO.Put ("Return => "); Text_IO.Put ("Return => ");
Print (Interp, Operand); Print (Interp, Operand);
Chain_Frame_Return (Interp, Interp.Stack, Operand); Chain_Frame_Return (Interp, Interp.Stack, Operand);
end Evaluate_Object; end Evaluate_Object;
procedure Evaluate_Syntax is procedure Evaluate_Syntax is
pragma Inline (Evaluate_Syntax); pragma Inline (Evaluate_Syntax);
Scode: Syntax_Code; Scode: Syntax_Code;
@ -2354,6 +2227,7 @@ Print (Interp, Operand);
Scode := Get_Car(Get_Frame_Operand(Interp.Stack)).Scode; Scode := Get_Car(Get_Frame_Operand(Interp.Stack)).Scode;
case Scode is case Scode is
when Begin_Syntax => when Begin_Syntax =>
-- not used. Evaluate_Group is used instead.
null; null;
when Define_Syntax => when Define_Syntax =>
Text_IO.Put_Line ("define syntax"); Text_IO.Put_Line ("define syntax");
@ -2377,13 +2251,13 @@ Print (Interp, Operand);
procedure Apply_Car_Procedure is procedure Apply_Car_Procedure is
begin begin
Pop_Frame; -- Done with the current frame Pop_Frame (Interp); -- Done with the current frame
Chain_Frame_Return (Interp, Interp.Stack, Get_Car(Args)); Chain_Frame_Return (Interp, Interp.Stack, Get_Car(Args));
end Apply_Car_Procedure; end Apply_Car_Procedure;
procedure Apply_Cdr_Procedure is procedure Apply_Cdr_Procedure is
begin begin
Pop_Frame; -- Done with the current frame Pop_Frame (Interp); -- Done with the current frame
Chain_Frame_Return (Interp, Interp.Stack, Get_Cdr(Args)); Chain_Frame_Return (Interp, Interp.Stack, Get_Cdr(Args));
end Apply_Cdr_Procedure; end Apply_Cdr_Procedure;
@ -2397,13 +2271,14 @@ Print (Interp, Operand);
-- if something else, error -- if something else, error
Car := Get_Car(Ptr); Car := Get_Car(Ptr);
if not Is_Integer(Car) then if not Is_Integer(Car) then
Ada.Text_IO.Put ("NOT INTEGER FOR ADD"); Print (Interp, Car);
raise Evaluation_Error; raise Evaluation_Error;
end if; end if;
Num := Num + Pointer_To_Integer(Car); Num := Num + Pointer_To_Integer(Car);
Ptr := Get_Cdr(Ptr); Ptr := Get_Cdr(Ptr);
end loop; end loop;
Pop_Frame; -- Done with the current frame Pop_Frame (Interp); -- Done with the current frame
Chain_Frame_Return (Interp, Interp.Stack, Integer_To_Pointer(Num)); Chain_Frame_Return (Interp, Interp.Stack, Integer_To_Pointer(Num));
end Apply_Add_Procedure; end Apply_Add_Procedure;
@ -2431,7 +2306,7 @@ Print (Interp, Operand);
end loop; end loop;
end if; end if;
Pop_Frame; -- Done with the current frame Pop_Frame (Interp); -- Done with the current frame
Chain_Frame_Return (Interp, Interp.Stack, Integer_To_Pointer(Num)); Chain_Frame_Return (Interp, Interp.Stack, Integer_To_Pointer(Num));
end Apply_Subtract_Procedure; end Apply_Subtract_Procedure;
@ -2541,9 +2416,256 @@ Print (Interp, Operand);
end case; end case;
end Apply; end Apply;
procedure Read_Object is procedure Fetch_Character is
begin begin
null; -- TODO: calculate Interp.Input.Row, Interp.Input.Column
if Interp.Input.Pos >= Interp.Input.Last then
if Interp.Input.Flags /= 0 then
-- An error has occurred or EOF has been reached previously.
-- Note calling this procedure after EOF results in an error.
Interp.Input.Iochar := (Error_Character, Object_Character'First);
--return;
raise IO_Error;
end if;
Interp.Input.Pos := Interp.Input.Data'First - 1;
begin
Read (Interp.Input.Stream.all, Interp.Input.Data, Interp.Input.Last);
exception
when others =>
-- The callee can raise an exception upon errors.
-- If an exception is raised, data read into the buffer
-- is also ignored.
Interp.Input.Flags := Interp.Input.Flags and IO_Error_Occurred;
Interp.Input.Iochar := (Error_Character, Object_Character'First);
--return;
raise IO_Error;
end;
if Interp.Input.Last < Interp.Input.Data'First then
-- The callee must read 0 bytes on EOF
Interp.Input.Flags := Interp.Input.Flags and IO_End_Reached;
Interp.Input.Iochar := (End_Character, Object_Character'First);
return;
end if;
end if;
Interp.Input.Pos := Interp.Input.Pos + 1;
Interp.Input.Iochar := (Normal_Character, Interp.Input.Data(Interp.Input.Pos));
end Fetch_Character;
function Is_White_Space (X: in Object_Character) return Standard.Boolean is
begin
return X = ' ' or else
X = Object_Character'Val(Standard.Character'Pos(Standard.ASCII.HT)) or else
X = Object_Character'Val(Standard.Character'Pos(Standard.ASCII.VT)) or else
X = Object_Character'Val(Standard.Character'Pos(Standard.ASCII.CR)) or else
X = Object_Character'Val(Standard.Character'Pos(Standard.ASCII.LF)) or else
X = Object_Character'Val(Standard.Character'Pos(Standard.ASCII.FF));
end Is_White_Space;
procedure Skip_Spaces_And_Comments is
begin
loop
exit when LC.Kind /= Normal_Character;
-- Normal character
if Is_White_Space(LC.Value) then
Fetch_Character;
elsif LC.Value = ';' then
-- Comment.
loop
Fetch_Character;
exit when LC.Kind = End_Character; -- EOF before LF
if LC.Kind = Normal_Character and then
LC.Value = Object_Character'Val(Standard.Character'Pos(Standard.ASCII.LF)) then
Fetch_Character; -- Read the next character after LF
exit;
end if;
end loop;
else
exit;
end if;
end loop;
end Skip_Spaces_And_Comments;
procedure Fetch_Token is
begin
if not Interp.LC_Unfetched then
Fetch_Character;
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
case LC.Value is
when '(' =>
Token.Set (Interp, Left_Parenthesis_Token, "(");
when ')' =>
Token.Set (Interp, Right_Parenthesis_Token, ")");
when '.' =>
Token.Set (Interp, Period_Token, ".");
when ''' =>
Token.Set (Interp, Single_Quote_Token, "'");
when '"' =>
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 = '\' 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 = '"' then
exit;
else
Token.Append_Character (Interp, LC.Value);
Fetch_Character;
end if;
end loop;
-- TODO:
when '#' =>
Fetch_Character;
-- TODO: t, false, etc
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.Value = '(' or else LC.Value = ')' or else
LC.Value = ''' or else LC.Value = '"' or else
LC.Value = '#' or else LC.Value = ';' or else
Is_White_Space(LC.Value) then
-- Unfetch the last character
Interp.LC_Unfetched := Standard.True;
exit;
end if;
end loop;
end case;
Text_IO.Put_Line (">>>>>>>>>>>>>>>>>>>>>>> Token: " & Interp.Token.Value.Ptr(1..Interp.Token.Value.Last));
end Fetch_Token;
procedure Read_List is
V: Object_Pointer;
Period: Standard.Boolean := Standard.False;
begin
<<Start_Over>>
Fetch_Token;
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_Return(Interp.Stack);
if V /= Nil_Pointer then
V := Reverse_Cons(V); -- TODO: GC
end if;
Pop_Frame (Interp);
Chain_Frame_Return (Interp, Interp.Stack, V);
when Period_Token =>
V := Get_Frame_Return(Interp.Stack);
if V = Nil_Pointer then
-- . immediately after (
raise Syntax_Error;
else
Period := Standard.True;
goto Start_Over;
end if;
when String_Token =>
V := Make_String (Interp.Self, Interp.Token.Value.Ptr.all(1..Interp.Token.Value.Last));
-- TODO: make V gc-aware
if Period then
else
Chain_Frame_Return (Interp, Interp.Stack, V);
end if;
when Identifier_Token =>
V := Make_Symbol (Interp.Self, Interp.Token.Value.Ptr.all(1..Interp.Token.Value.Last));
-- TODO: make V gc-aware
if Period then
else
Chain_Frame_Return (Interp, Interp.Stack, V);
end if
when others =>
-- TODO: set various error info
raise Syntax_Error;
end case;
end Read_List;
procedure Close_List is
V: Object_Pointer;
begin
V := Get_Frame_Return(Interp.Stack);
pragma Assert (Get_Cdr(V) = Nil_Pointer);
Pop_Frame (Interp); -- Done with the current frame
Chain_Frame_Return (Interp, Interp.Stack, Get_Car(V));
end Close_List;
procedure Read_Object is
V: Object_Pointer;
begin
Fetch_Token;
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 String_Token =>
V := Make_String (Interp.Self, Interp.Token.Value.Ptr.all(1..Interp.Token.Value.Last));
-- TODO: make V gc-aware
Pop_Frame (Interp); -- Done with the current frame
Chain_Frame_Return (Interp, Interp.Stack, V);
when Identifier_Token =>
V := Make_Symbol (Interp.Self, Interp.Token.Value.Ptr.all(1..Interp.Token.Value.Last));
-- TODO: make V gc-aware
Pop_Frame (Interp); -- Done with the current frame
Chain_Frame_Return (Interp, Interp.Stack, V);
when others =>
-- TODO: set various error info
raise Syntax_Error;
end case;
end Read_Object; end Read_Object;
begin begin
@ -2605,22 +2727,14 @@ Print (Interp, Operand);
-- The apply operation produces the final result and sets it to the -- The apply operation produces the final result and sets it to the
-- parent frame while removing the apply frame. -- parent frame while removing the apply frame.
-- ----------------------------------------------------------------- -- -----------------------------------------------------------------
-- top/bottom| Opcode_Exit | Nil | 3 -- top/bottom| Opcode_Exit | Nil | (3)
-- The caller must push some frames before calling this procedure
Interp.Stack := Nil_Pointer; pragma Assert (Interp.Stack /= Nil_Pointer);
-- Push a pseudo-frame to terminate the evaluation loop
Push_Frame (Opcode_Exit, Nil_Pointer);
-- Push the actual frame for evaluation
Push_Frame (Opcode_Evaluate_Object, Source);
loop loop
case Get_Frame_Opcode(Interp.Stack) is case Get_Frame_Opcode(Interp.Stack) is
when Opcode_Exit => when Opcode_Exit =>
Result := Get_Frame_Return (Interp.Stack);
Pop_Frame;
exit; exit;
when Opcode_Evaluate_Object => when Opcode_Evaluate_Object =>
@ -2640,24 +2754,98 @@ Print (Interp, Operand);
when Opcode_Read_Object => when Opcode_Read_Object =>
Read_Object; Read_Object;
when Opcode_Read_List =>
Read_List;
when Opcode_Close_List =>
Close_List;
end case; end case;
end loop; end loop;
-- the stack must be empty when the loop is terminated -- the stack must be empty when the loop is terminated
pragma Assert (Interp.Stack = Nil_Pointer); --pragma Assert (Interp.Stack = Nil_Pointer);
exception exception
when Stream_End_Error =>
raise;
when others => when others =>
Text_IO.Put_Line ("EXCEPTION OCCURRED"); Text_IO.Put_Line ("EXCEPTION OCCURRED");
-- TODO: restore stack frame??? -- TODO: restore stack frame???
-- TODO: restore envirronemtn frame??? -- TODO: restore envirronemtn frame???
raise;
end Execute;
procedure Evaluate (Interp: in out Interpreter_Record;
Source: in Object_Pointer;
Result: out Object_Pointer) is
begin
pragma Assert (Interp.Stack = Nil_Pointer);
Interp.Stack := Nil_Pointer;
-- Push a pseudo-frame to terminate the evaluation loop
Push_Frame (Interp, Opcode_Exit, Nil_Pointer);
-- Push the actual frame for evaluation
Push_Frame (Interp, Opcode_Evaluate_Object, Source);
Execute (Interp);
pragma Assert (Get_Frame_Opcode(Interp.Stack) = Opcode_Exit);
Result := Get_Frame_Return (Interp.Stack);
-- There must be only 1 value chained to the top-level frame
-- once evaluation is over.
pragma Assert (Get_Cdr(Result) = Nil_Pointer);
-- Get the only value chained
Result := Get_Car(Result);
Pop_Frame (Interp);
pragma Assert (Interp.Stack = Nil_Pointer);
end Evaluate; end Evaluate;
procedure Run_Loop (Interp: in out Interpreter_Record; procedure Run_Loop (Interp: in out Interpreter_Record;
Result: out Object_Pointer) is Result: out Object_Pointer) is
-- standard read-eval-print loop -- standard read-eval-print loop
begin begin
null; Result := Nil_Pointer;
loop
pragma Assert (Interp.Stack = Nil_Pointer);
Interp.Stack := Nil_Pointer;
Push_Frame (Interp, Opcode_Exit, Nil_Pointer);
--Push_Frame (Interp, Opcode_Print, Nil_Pointer);
--Push_Frame (Interp, Opcode_Evaluate_Object, Nil_Pointer);
Push_Frame (Interp, Opcode_Read_Object, Nil_Pointer);
Execute (Interp);
pragma Assert (Get_Frame_Opcode(Interp.Stack) = Opcode_Exit);
-- TODO: this result must be kept at some where that GC dowsn't sweep.
Result := Get_Frame_Return (Interp.Stack);
pragma Assert (Get_Cdr(Result) = Nil_Pointer);
Result := Get_Car(Result);
Pop_Frame (Interp);
Ada.Text_IO.Put ("REsULT>>>>>");
Print (Interp, Result);
pragma Assert (Interp.Stack = Nil_Pointer);
Text_IO.Put_Line (">>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> LOOP ITERATION XXXXXX CHECKPOINT");
end loop;
exception
when Stream_End_Error =>
-- this is not a real error. this indicates the end of input stream.
Text_IO.Put_LINE ("=== BYE ===");
when others =>
TEXT_IO.PUT_LINE ("ERROR ERROR ERROR");
raise;
end Run_Loop; end Run_Loop;
----------------------------------------------------------------------------- -----------------------------------------------------------------------------

7
lib/h2-scheme.ads
View File

@ -333,7 +333,6 @@ package H2.Scheme is
Iochar: IO_Character_Record; -- the last character read. Iochar: IO_Character_Record; -- the last character read.
end record; end record;
-- ----------------------------------------------------------------------------- -- -----------------------------------------------------------------------------
type Trait_Mask is mod 2 ** System.Word_Size; type Trait_Mask is mod 2 ** System.Word_Size;
@ -402,8 +401,8 @@ procedure Make_Test_Object (Interp: in out Interpreter_Record; Result: out Objec
Stream: in out Stream_Record'Class); Stream: in out Stream_Record'Class);
-- Source must be open for Read() to work. -- Source must be open for Read() to work.
procedure Read (Interp: in out Interpreter_Record; --procedure Read (Interp: in out Interpreter_Record;
Result: out Object_Pointer); -- Result: out Object_Pointer);
procedure Evaluate (Interp: in out Interpreter_Record; procedure Evaluate (Interp: in out Interpreter_Record;
Source: in Object_Pointer; Source: in Object_Pointer;
@ -444,6 +443,7 @@ private
Identifier_Token, Identifier_Token,
Left_Parenthesis_Token, Left_Parenthesis_Token,
Right_Parenthesis_Token, Right_Parenthesis_Token,
Period_Token,
Single_Quote_Token, Single_Quote_Token,
String_Token String_Token
); );
@ -475,6 +475,7 @@ private
Input: IO_Pointer := null; Input: IO_Pointer := null;
Token: Token_Record; Token: Token_Record;
LC_Unfetched: Standard.Boolean := Standard.False;
end record; end record;
end H2.Scheme; end H2.Scheme;