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|
with
Ada.Unchecked_Deallocation;
package body Packrat.Lexer is
procedure Free_Array is new Ada.Unchecked_Deallocation
(Object => Element_Array, Name => Element_Array_Access);
procedure Initialize
(This : in out Combinator_Result) is
begin
null;
end Initialize;
procedure Adjust
(This : in out Combinator_Result) is
begin
if This.Value /= null then
declare
New_Array : Element_Array_Access :=
new Element_Array (1 .. This.Value.all'Length);
begin
New_Array.all := This.Value.all;
This.Value := New_Array;
end;
end if;
end Adjust;
procedure Finalize
(This : in out Combinator_Result) is
begin
if This.Value /= null then
Free_Array (This.Value);
end if;
end Finalize;
function "="
(Left, Right : in Combinator_Result)
return Boolean
is
Left_Valsize, Right_Valsize : Natural;
begin
if Left.Value = null then
Left_Valsize := 0;
else
Left_Valsize := Left.Value.all'Length;
end if;
if Right.Value = null then
Right_Valsize := 0;
else
Right_Valsize := Right.Value.all'Length;
end if;
return Left.Length = Right.Length and
Left.Status = Right.Status and
Left_Valsize = Right_Valsize and
(Left_Valsize = 0 or else Left.Value.all = Right.Value.all);
end "=";
function Create_Result
(Length : in Natural;
Status : in Result_Status;
Value : in Element_Array)
return Combinator_Result
is
This : Combinator_Result;
begin
This.Length := Length;
This.Status := Status;
This.Value := new Element_Array (1 .. Value'Length);
This.Value.all := Value;
return This;
end Create_Result;
function Join
(Left, Right : in Combinator_Result)
return Combinator_Result
is
Merge : Combinator_Result;
Left_Valsize, Right_Valsize, Total_Valsize : Natural;
begin
if Left.Value /= null then
Left_Valsize := Left.Value.all'Length;
else
Left_Valsize := 0;
end if;
if Right.Value /= null then
Right_Valsize := Right.Value.all'Length;
else
Right_Valsize := 0;
end if;
Total_Valsize := Left_Valsize + Right_Valsize;
if Left.Status = Success or Left.Status = Optional_More then
Merge.Length := Left.Length + Right.Length;
Merge.Status := Right.Status;
if Total_Valsize > 0 then
Merge.Value := new Element_Array (1 .. Total_Valsize);
if Left.Value /= null then
Merge.Value.all (1 .. Left_Valsize) := Left.Value.all;
end if;
if Right.Value /= null then
Merge.Value.all (Left_Valsize + 1 .. Total_Valsize) := Right.Value.all;
end if;
end if;
return Merge;
elsif Left.Status = Needs_More then
Merge := Left;
Merge.Status := Failure;
return Merge;
else
return Left;
end if;
end Join;
procedure Stamp
(Input : in Element_Array;
Context : in out Lexer_Context) is
begin
null;
end Stamp;
procedure Ignore
(Input : in Element_Array;
Context : in out Lexer_Context) is
begin
null;
end Ignore;
function Scan
(Input : in Element_Array;
Context : in out Lexer_Context)
return Gen_Tokens.Token_Array
is
Result : Gen_Tokens.Token_Array (1 .. 0);
begin
return Result;
end Scan;
procedure Scan_Set
(Input : in Element_Array;
Context : in out Lexer_Context;
Output : out Gen_Tokens.Token_Array) is
begin
null;
end Scan_Set;
function Scan_Only
(Input : in Element_Array;
Context : in out Lexer_Context)
return Gen_Tokens.Token_Array
is
Result : Gen_Tokens.Token_Array (1 .. 0);
begin
return Result;
end Scan_Only;
procedure Scan_Set_Only
(Input : in Element_Array;
Context : in out Lexer_Context;
Output : out Gen_Tokens.Token_Array) is
begin
null;
end Scan_Set_Only;
function Scan_With
(Input : in Element_Array;
Context : in out Lexer_Context)
return Gen_Tokens.Token_Array
is
Result : Gen_Tokens.Token_Array (1 .. 0);
begin
return Result;
end Scan_With;
procedure Scan_Set_With
(Input : in Element_Array;
Context : in out Lexer_Context;
Output : out Gen_Tokens.Token_Array) is
begin
null;
end Scan_Set_With;
function Sequence
(Input : in Element_Array;
Start : in Positive)
return Combinator_Result
is
Result : Combinator_Result := Create_Result (0, Success, Empty_Array);
Position : Positive := Start;
begin
if Start > Input'Last then
return Empty_Fail;
end if;
for C of Params loop
if Position > Input'Last then
Result.Status := Needs_More;
exit;
end if;
Result := Join (Result, C (Input, Position));
exit when Result.Status = Failure;
Position := Start + Result.Length;
end loop;
return Result;
end Sequence;
function Count
(Input : in Element_Array;
Start : in Positive)
return Combinator_Result
is
Result : Combinator_Result := Create_Result (0, Success, Empty_Array);
Position : Positive := Start;
begin
if Start > Input'Last then
return Empty_Fail;
end if;
for I in Integer range 1 .. Number loop
if Position > Input'Last then
Result.Status := Needs_More;
exit;
end if;
Result := Join (Result, Param (Input, Position));
exit when Result.Status = Failure;
Position := Start + Result.Length;
end loop;
return Result;
end Count;
function Many
(Input : in Element_Array;
Start : in Positive)
return Combinator_Result
is
Result : Combinator_Result := Create_Result (0, Success, Empty_Array);
Temp : Combinator_Result;
Position : Positive := Start;
Counter : Natural := 0;
begin
if Start > Input'Last then
return Empty_Fail;
end if;
loop
exit when Position > Input'Last;
Temp := Param (Input, Position);
exit when Temp.Status = Failure or Temp.Status = Needs_More;
Result := Join (Result, Temp);
Counter := Counter + 1;
Position := Start + Result.Length;
end loop;
if Counter < Minimum then
if Position > Input'Last or Temp.Status = Needs_More then
Result.Status := Needs_More;
else
Result.Status := Failure;
end if;
elsif Position > Input'Last or Temp.Status = Needs_More then
Result.Status := Optional_More;
else
Result.Status := Success;
end if;
return Result;
end Many;
function Many_Until
(Input : in Element_Array;
Start : in Positive)
return Combinator_Result
is
Result : Combinator_Result := Create_Result (0, Success, Empty_Array);
Temp : Combinator_Result;
Position : Positive := Start;
Counter : Natural := 0;
begin
if Start > Input'Last then
return Empty_Fail;
end if;
loop
exit when Position > Input'Last;
Temp := Param (Input, Position);
exit when Temp.Status = Failure or Temp.Status = Needs_More or Test (Input (Position));
Result := Join (Result, Temp);
Counter := Counter + 1;
Position := Start + Result.Length;
end loop;
if Counter < Minimum then
if Position > Input'Last or Temp.Status = Needs_More then
Result.Status := Needs_More;
else
Result.Status := Failure;
end if;
elsif Position > Input'Last then
Result.Status := Needs_More;
elsif Temp.Status = Needs_More and Test (Input (Position)) then
Result.Status := Optional_More;
elsif Test (Input (Position)) then
Result.Status := Success;
else
Result.Status := Failure;
end if;
return Result;
end Many_Until;
function Satisfy
(Input : in Element_Array;
Start : in Positive)
return Combinator_Result is
begin
if Start > Input'Last then
return Empty_Fail;
elsif Test (Input (Start)) then
return Create_Result (1, Success, (1 => Input (Start)));
else
return Empty_Fail;
end if;
end Satisfy;
function Satisfy_With
(Input : in Element_Array;
Start : in Positive)
return Combinator_Result is
begin
if Start > Input'Last then
return Empty_Fail;
elsif Test (Change (Input (Start))) then
return Create_Result (1, Success, (1 => Input (Start)));
else
return Empty_Fail;
end if;
end Satisfy_With;
function Match
(Input : in Element_Array;
Start : in Positive)
return Combinator_Result is
begin
if Start > Input'Last then
return Empty_Fail;
elsif Input (Start) = Item then
return Create_Result (1, Success, (1 => Item));
else
return Empty_Fail;
end if;
end Match;
function Match_With
(Input : in Element_Array;
Start : in Positive)
return Combinator_Result is
begin
if Start > Input'Last then
return Empty_Fail;
elsif Change (Input (Start)) = Item then
return Create_Result (1, Success, (1 => Input (Start)));
else
return Empty_Fail;
end if;
end Match_With;
function Multimatch
(Input : in Element_Array;
Start : in Positive)
return Combinator_Result
is
Current_Offset : Natural := 0;
begin
if Items'Length = 0 then
return Create_Result (0, Success, Empty_Array);
end if;
if Input'Last - Start + 1 <= 0 then
return Empty_Fail;
end if;
while Input (Start + Current_Offset) = Items (Items'First + Current_Offset) loop
if Items'First + Current_Offset = Items'Last then
return Create_Result (Current_Offset + 1, Success, Items);
elsif Start + Current_Offset = Input'Last then
return Create_Result (Current_Offset + 1, Needs_More, Input (Start .. Input'Last));
end if;
Current_Offset := Current_Offset + 1;
end loop;
return Create_Result (Current_Offset, Failure, Input (Start .. Start + Current_Offset - 1));
end Multimatch;
function Take
(Input : in Element_Array;
Start : in Positive)
return Combinator_Result is
begin
if Start > Input'Last then
return Empty_Fail;
elsif Start + Number - 1 > Input'Last then
return Create_Result (Input'Last - Start + 1, Needs_More, Input (Start .. Input'Last));
else
return Create_Result (Number, Success, Input (Start .. Start + Number - 1));
end if;
end Take;
function Take_While
(Input : in Element_Array;
Start : in Positive)
return Combinator_Result
is
Finish : Positive := Start;
Status : Result_Status;
begin
if Start > Input'Last or else not Test (Input (Start)) then
return Empty_Fail;
end if;
while Finish <= Input'Last and then Test (Input (Finish)) loop
Finish := Finish + 1;
end loop;
if Finish > Input'Last then
Status := Optional_More;
else
Status := Success;
end if;
return Create_Result (Finish - Start, Status, Input (Start .. Finish - 1));
end Take_While;
function Take_Until
(Input : in Element_Array;
Start : in Positive)
return Combinator_Result
is
Finish : Positive := Start;
Status : Result_Status;
begin
if Start > Input'Last or else Test (Input (Start)) then
return Empty_Fail;
end if;
while Finish <= Input'Last and then not Test (Input (Finish)) loop
Finish := Finish + 1;
end loop;
if Finish > Input'Last then
Status := Optional_More;
else
Status := Success;
end if;
return Create_Result (Finish - Start, Status, Input (Start .. Finish - 1));
end Take_Until;
function Line_End
(Input : in Element_Array;
Start : in Positive)
return Combinator_Result is
begin
if Start > Input'Last then
return Empty_Fail;
elsif Input (Start) = EOL_Item then
return Create_Result (1, Success, (1 => EOL_Item));
else
return Empty_Fail;
end if;
end Line_End;
function Input_End
(Input : in Element_Array;
Start : in Positive)
return Combinator_Result is
begin
if Start > Input'Last then
return Empty_Fail;
elsif Input (Start) = EOF_Item then
return Create_Result (1, Success, (1 => EOF_Item));
else
return Empty_Fail;
end if;
end Input_End;
end Packrat.Lexer;
|