Packrat.Lexer Stamp, Ignore, Scan, Scan_Only functions/procedures completed

2 files changed, 320 insertions, 155 deletions

diff --git a/src/packrat-lexer.adb b/src/packrat-lexer.adb
index 7cbd527..77ebf9f 100644
--- a/src/packrat-lexer.adb
+++ b/src/packrat-lexer.adb
@@ -13,32 +13,30 @@ package body Packrat.Lexer is
 
 
     procedure Initialize
-           (This : in out Combinator_Result) is
+           (This : in out Lexer_Context) is
     begin
         null;
     end Initialize;
 
 
     procedure Adjust
-           (This : in out Combinator_Result) is
+           (This : in out Lexer_Context)
+    is
+        New_Array : Element_Array_Access;
     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;
+        if This.Pass_Forward /= null then
+            New_Array := new Element_Array (1 .. This.Pass_Forward.all'Length);
+            New_Array.all := This.Pass_Forward.all;
+            This.Pass_Forward := New_Array;
         end if;
     end Adjust;
 
 
     procedure Finalize
-           (This : in out Combinator_Result) is
+           (This : in out Lexer_Context) is
     begin
-        if This.Value /= null then
-            Free_Array (This.Value);
+        if This.Pass_Forward /= null then
+            Free_Array (This.Pass_Forward);
         end if;
     end Finalize;
 
@@ -46,85 +44,46 @@ package body Packrat.Lexer is
 
 
 
-    function "="
-           (Left, Right : in Combinator_Result)
-        return Boolean
-    is
-        Left_Valsize, Right_Valsize : Natural;
+    procedure Finalize
+           (This : in out Input_Container) is
     begin
-        if Left.Value = null then
-            Left_Valsize := 0;
-        else
-            Left_Valsize := Left.Value.all'Length;
+        if This.Dealloc then
+            Free_Array (This.Data);
         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 "=";
+    end Finalize;
 
 
+    function Pass_Input
+           (Passed, Continuing : in Element_Array_Access)
+        return Input_Container is
+    begin
+        if Passed = null then
+            return This : Input_Container do
+                This.Data := Continuing;
+                This.Dealloc := False;
+            end return;
+        else
+            return This : Input_Container do
+                This.Data := new Element_Array (1 .. Passed'Length + Continuing'Length);
+                This.Data (1 .. Passed'Length) := Passed.all;
+                This.Data (Passed'Length + 1 .. This.Data'Last) := Continuing.all;
+                This.Dealloc := True;
+            end return;
+        end if;
+    end Pass_Input;
 
 
 
-    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;
+        return Combinator_Result is
     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;
+            return (Integer'Max (Left.Finish, Right.Finish), Right.Status);
         elsif Left.Status = Needs_More then
-            Merge := Left;
-            Merge.Status := Failure;
-            return Merge;
+            return (Left.Finish, Failure);
         else
             return Left;
         end if;
@@ -134,33 +93,174 @@ package body Packrat.Lexer is
 
 
 
-    procedure Stamp
+    function Stamp
            (Input   : in     Element_Array;
-            Context : in out Lexer_Context) is
+            Context : in out Lexer_Context)
+        return Component_Result
+    is
+        Current_Result : Combinator_Result :=
+            Combo (Input, Context.Position);
     begin
-        null;
+        if  Context.Status /= Success or Context.Position > Input'Last or
+            Context.Empty_Labels.Contains (Label)
+        then
+            return Component_Failure;
+        end if;
+
+        if (Current_Result.Status = Needs_More and not Context.Allow_Incomplete) or
+            Current_Result.Status = Failure
+        then
+            Context.Error_Labels.Append (Label);
+            return Component_Failure;
+        end if;
+
+        if (Current_Result.Status = Optional_More and not Context.Allow_Incomplete) or
+            Current_Result.Status = Success
+        then
+            Context.Result_So_Far.Append (Gen_Tokens.Create
+               (Label,
+                Context.Position + Context.Offset,
+                Current_Result.Finish + Context.Offset,
+                Input (Context.Position .. Current_Result.Finish)));
+            if Current_Result.Finish = 0 then
+                Context.Empty_Labels.Insert (Label);
+            else
+                Context.Empty_Labels.Clear;
+                Context.Position := Current_Result.Finish + 1;
+            end if;
+        else
+            Context.Status := Current_Result.Status;
+            Context.Pass_Forward := new Element_Array
+                (1 .. Current_Result.Finish - Context.Position + 1);
+            Context.Pass_Forward.all := Input (Context.Position .. Current_Result.Finish);
+            Context.Empty_Labels.Clear;
+        end if;
+
+        Context.Error_Labels.Clear;
+        return Component_Success;
     end Stamp;
 
 
-    procedure Ignore
+    function Ignore
            (Input   : in     Element_Array;
-            Context : in out Lexer_Context) is
+            Context : in out Lexer_Context)
+        return Component_Result
+    is
+        Current_Result : Combinator_Result :=
+            Combo (Input, Context.Position);
     begin
-        null;
+        if  Context.Status /= Success or Context.Position > Input'Last or
+            Context.Empty_Labels.Contains (Label)
+        then
+            return Component_Failure;
+        end if;
+
+        if (Current_Result.Status = Needs_More and not Context.Allow_Incomplete) or
+            Current_Result.Status = Failure
+        then
+            Context.Error_Labels.Append (Label);
+            return Component_Failure;
+        end if;
+
+        if (Current_Result.Status = Optional_More and not Context.Allow_Incomplete) or
+            Current_Result.Status = Success
+        then
+            if Current_Result.Finish = 0 then
+                Context.Empty_Labels.Insert (Label);
+            else
+                Context.Empty_Labels.Clear;
+                Context.Position := Current_Result.Finish + 1;
+            end if;
+        else
+            Context.Status := Current_Result.Status;
+            Context.Pass_Forward := new Element_Array
+                (1 .. Current_Result.Finish - Context.Position + 1);
+            Context.Pass_Forward.all := Input (Context.Position .. Current_Result.Finish);
+            Context.Empty_Labels.Clear;
+        end if;
+
+        Context.Error_Labels.Clear;
+        return Component_Success;
     end Ignore;
 
 
 
 
 
+    procedure Tidy_Context
+           (Details     : in out Lexer_Context;
+            Number_Comp : in     Ada.Containers.Count_Type) is
+    begin
+        if Details.Pass_Forward /= null then
+            Free_Array (Details.Pass_Forward);
+            Details.Pass_Forward := null;
+        end if;
+
+        Details.Result_So_Far.Clear;
+        Details.Empty_Labels.Clear;
+        Details.Error_Labels.Clear;
+        Details.Error_Labels.Reserve_Capacity (Number_Comp);
+
+        Details.Offset := Details.Offset + Details.Position - 1;
+        Details.Position := 1;
+        Details.Status := Success;
+    end Tidy_Context;
+
+
+    procedure Raise_Lexer_Error
+           (Label_List : in Label_Vectors.Vector;
+            Position   : in Positive)
+    is
+        Error_Info_List : Errors.Error_Info_Array
+           (Label_List.First_Index .. Label_List.Last_Index);
+    begin
+        for I in Integer range Error_Info_List'First .. Error_Info_List'Last loop
+            Error_Info_List (I).Symbol := +Label_Enum'Image (Label_List.Element (I));
+            Error_Info_List (I).Position := Position;
+        end loop;
+        raise Lexer_Error with Errors.Encode_Array (Error_Info_List);
+    end Raise_Lexer_Error;
+
+
+    function Token_Vector_To_Array
+           (Input_Vector : in Token_Vectors.Vector)
+        return Gen_Tokens.Token_Array
+    is
+        Result_Array : Gen_Tokens.Token_Array (1 .. Integer (Input_Vector.Length));
+    begin
+        for I in Integer range 1 .. Integer (Input_Vector.Length) loop
+            Result_Array (I) := Input_Vector.Element (I);
+        end loop;
+        return Result_Array;
+    end Token_Vector_To_Array;
+
+
     function Scan
            (Input   : in     Element_Array;
             Context : in out Lexer_Context)
         return Gen_Tokens.Token_Array
     is
-        Result : Gen_Tokens.Token_Array (1 .. 0);
+        Real_Input : Input_Container :=
+            Pass_Input (Context.Pass_Forward, Input'Unrestricted_Access);
+        Raise_Error : Boolean;
     begin
-        return Result;
+        Tidy_Context (Context, Components'Length);
+        Context.Allow_Incomplete := not (Input = Empty_Array);
+
+        while Context.Status = Success and Context.Position <= Real_Input.Data'Length loop
+            Raise_Error := True;
+            for C of Components loop
+                if C (Real_Input.Data.all, Context) = Component_Success then
+                    Raise_Error := False;
+                    exit;
+                end if;
+            end loop;
+            if Raise_Error then
+                Raise_Lexer_Error (Context.Error_Labels, Context.Position);
+            end if;
+        end loop;
+
+        return Token_Vector_To_Array (Context.Result_So_Far);
     end Scan;
 
 
@@ -169,14 +269,32 @@ package body Packrat.Lexer is
             Context : in out Lexer_Context)
         return Gen_Tokens.Token_Array
     is
-        Result : Gen_Tokens.Token_Array (1 .. 0);
+        Real_Input : Input_Container :=
+            Pass_Input (Context.Pass_Forward, Input'Unrestricted_Access);
+        Raise_Error : Boolean;
     begin
-        return Result;
+        Tidy_Context (Context, Components'Length);
+        Context.Allow_Incomplete := False;
+
+        while Context.Status = Success and Context.Position <= Real_Input.Data'Length loop
+            Raise_Error := True;
+            for C of Components loop
+                if C (Real_Input.Data.all, Context) = Component_Success then
+                    Raise_Error := False;
+                    exit;
+                end if;
+            end loop;
+            if Raise_Error then
+                Raise_Lexer_Error (Context.Error_Labels, Context.Position);
+            end if;
+        end loop;
+
+        return Token_Vector_To_Array (Context.Result_So_Far);
     end Scan_Only;
 
 
     function Scan_With
-           (Input   : in     Lexer_With_Input;
+           (Input   : in     With_Input;
             Context : in out Lexer_Context)
         return Gen_Tokens.Token_Array
     is
@@ -196,7 +314,7 @@ package body Packrat.Lexer is
 
 
     procedure Scan_Set_With
-           (Input   : in     Lexer_With_Input;
+           (Input   : in     With_Input;
             Context : in out Lexer_Context;
             Output  :    out Gen_Tokens.Token_Array) is
     begin
@@ -212,7 +330,7 @@ package body Packrat.Lexer is
             Start : in Positive)
         return Combinator_Result
     is
-        Result : Combinator_Result := Create_Result (0, Success, Empty_Array);
+        Result : Combinator_Result := (0, Success);
         Position : Positive := Start;
     begin
         if Start > Input'Last then
@@ -225,7 +343,7 @@ package body Packrat.Lexer is
             end if;
             Result := Join (Result, C (Input, Position));
             exit when Result.Status = Failure;
-            Position := Start + Result.Length;
+            Position := Result.Finish + 1;
         end loop;
         return Result;
     end Sequence;
@@ -236,7 +354,7 @@ package body Packrat.Lexer is
             Start : in Positive)
         return Combinator_Result
     is
-        Result : Combinator_Result := Create_Result (0, Success, Empty_Array);
+        Result : Combinator_Result := (0, Success);
         Position : Positive := Start;
     begin
         if Start > Input'Last then
@@ -249,7 +367,7 @@ package body Packrat.Lexer is
             end if;
             Result := Join (Result, Param (Input, Position));
             exit when Result.Status = Failure;
-            Position := Start + Result.Length;
+            Position := Result.Finish + 1;
         end loop;
         return Result;
     end Count;
@@ -260,7 +378,7 @@ package body Packrat.Lexer is
             Start : in Positive)
         return Combinator_Result
     is
-        Result : Combinator_Result := Create_Result (0, Success, Empty_Array);
+        Result : Combinator_Result := (0, Success);
         Temp   : Combinator_Result;
         Position : Positive := Start;
         Counter  : Natural := 0;
@@ -274,7 +392,7 @@ package body Packrat.Lexer is
             exit when Temp.Status = Failure or Temp.Status = Needs_More;
             Result := Join (Result, Temp);
             Counter := Counter + 1;
-            Position := Start + Result.Length;
+            Position := Result.Finish + 1;
         end loop;
         if Counter < Minimum then
             if Position > Input'Last or Temp.Status = Needs_More then
@@ -296,7 +414,7 @@ package body Packrat.Lexer is
             Start : in Positive)
         return Combinator_Result
     is
-        Result : Combinator_Result := Create_Result (0, Success, Empty_Array);
+        Result : Combinator_Result := (0, Success);
         Temp   : Combinator_Result;
         Position : Positive := Start;
         Counter  : Natural := 0;
@@ -310,7 +428,7 @@ package body Packrat.Lexer is
             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;
+            Position := Result.Finish + 1;
         end loop;
         if Counter < Minimum then
             if Position > Input'Last or Temp.Status = Needs_More then
@@ -342,7 +460,7 @@ package body Packrat.Lexer is
         if Start > Input'Last then
             return Empty_Fail;
         elsif Test (Input (Start)) then
-            return Create_Result (1, Success, (1 => Input (Start)));
+            return (Start, Success);
         else
             return Empty_Fail;
         end if;
@@ -357,7 +475,7 @@ package body Packrat.Lexer is
         if Start > Input'Last then
             return Empty_Fail;
         elsif Test (Change (Input (Start))) then
-            return Create_Result (1, Success, (1 => Input (Start)));
+            return (Start, Success);
         else
             return Empty_Fail;
         end if;
@@ -372,7 +490,7 @@ package body Packrat.Lexer is
         if Start > Input'Last then
             return Empty_Fail;
         elsif Input (Start) = Item then
-            return Create_Result (1, Success, (1 => Item));
+            return (Start, Success);
         else
             return Empty_Fail;
         end if;
@@ -387,7 +505,7 @@ package body Packrat.Lexer is
         if Start > Input'Last then
             return Empty_Fail;
         elsif Change (Input (Start)) = Item then
-            return Create_Result (1, Success, (1 => Input (Start)));
+            return (Start, Success);
         else
             return Empty_Fail;
         end if;
@@ -402,7 +520,7 @@ package body Packrat.Lexer is
         Current_Offset : Natural := 0;
     begin
         if Items'Length = 0 then
-            return Create_Result (0, Success, Empty_Array);
+            return (0, Success);
         end if;
 
         if Input'Last - Start + 1 <= 0 then
@@ -411,13 +529,17 @@ package body Packrat.Lexer is
 
         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);
+                return (Start + Current_Offset, Success);
             elsif Start + Current_Offset = Input'Last then
-                return Create_Result (Current_Offset + 1, Needs_More, Input (Start .. Input'Last));
+                return (Start + Current_Offset, Needs_More);
             end if;
             Current_Offset := Current_Offset + 1;
         end loop;
-        return Create_Result (Current_Offset, Failure, Input (Start .. Start + Current_Offset - 1));
+        if Current_Offset = 0 then
+            return Empty_Fail;
+        else
+            return (Start + Current_Offset - 1, Failure);
+        end if;
     end Multimatch;
 
 
@@ -429,9 +551,9 @@ package body Packrat.Lexer is
         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));
+            return (Input'Last, Needs_More);
         else
-            return Create_Result (Number, Success, Input (Start .. Start + Number - 1));
+            return (Start + Number - 1, Success);
         end if;
     end Take;
 
@@ -455,7 +577,7 @@ package body Packrat.Lexer is
         else
             Status := Success;
         end if;
-        return Create_Result (Finish - Start, Status, Input (Start .. Finish - 1));
+        return (Finish - 1, Status);
     end Take_While;
 
 
@@ -478,7 +600,7 @@ package body Packrat.Lexer is
         else
             Status := Success;
         end if;
-        return Create_Result (Finish - Start, Status, Input (Start .. Finish - 1));
+        return (Finish - 1, Status);
     end Take_Until;
 
 
@@ -493,7 +615,7 @@ package body Packrat.Lexer is
         if Start > Input'Last then
             return Empty_Fail;
         elsif Input (Start) = EOL_Item then
-            return Create_Result (1, Success, (1 => EOL_Item));
+            return (Start, Success);
         else
             return Empty_Fail;
         end if;
@@ -508,7 +630,7 @@ package body Packrat.Lexer is
         if Start > Input'Last then
             return Empty_Fail;
         elsif Input (Start) = EOF_Item then
-            return Create_Result (1, Success, (1 => EOF_Item));
+            return (Start, Success);
         else
             return Empty_Fail;
         end if;
diff --git a/src/packrat-lexer.ads b/src/packrat-lexer.ads
index 2d152bf..0cd5c78 100644
--- a/src/packrat-lexer.ads
+++ b/src/packrat-lexer.ads
@@ -2,7 +2,8 @@
 
 private with
 
-    Ada.Containers.Vectors;
+    Ada.Containers.Vectors,
+    Ada.Containers.Ordered_Sets;
 
 
 generic
@@ -16,7 +17,7 @@ generic
 package Packrat.Lexer is
 
 
-    type Combinator_Result is new Ada.Finalization.Controlled with private;
+    type Combinator_Result is private;
 
     type Combinator is access function
            (Input : in Element_Array;
@@ -25,10 +26,6 @@ package Packrat.Lexer is
 
     type Combinator_Array is array (Positive range <>) of Combinator;
 
-    function "="
-           (Left, Right : in Combinator_Result)
-        return Boolean;
-
 
 
 
@@ -39,16 +36,19 @@ package Packrat.Lexer is
 
 
 
-    type Lexer_Component is access procedure
+    type Component_Result is private;
+
+    type Component is access function
            (Input   : in     Element_Array;
-            Context : in out Lexer_Context);
+            Context : in out Lexer_Context)
+        return Component_Result;
 
-    type Component_Array is array (Positive range <>) of Lexer_Component;
+    type Component_Array is array (Positive range <>) of Component;
 
 
 
 
-    type Lexer_With_Input is access function
+    type With_Input is access function
            return Element_Array;
 
 
@@ -60,9 +60,10 @@ package Packrat.Lexer is
                (Input : in Element_Array;
                 Start : in Positive)
             return Combinator_Result;
-    procedure Stamp
+    function Stamp
            (Input   : in     Element_Array;
-            Context : in out Lexer_Context);
+            Context : in out Lexer_Context)
+        return Component_Result;
 
     generic
         Label : in Label_Enum;
@@ -70,9 +71,10 @@ package Packrat.Lexer is
                (Input : in Element_Array;
                 Start : in Positive)
             return Combinator_Result;
-    procedure Ignore
+    function Ignore
            (Input   : in     Element_Array;
-            Context : in out Lexer_Context);
+            Context : in out Lexer_Context)
+        return Component_Result;
 
 
 
@@ -94,7 +96,7 @@ package Packrat.Lexer is
     generic
         Components : in Component_Array;
     function Scan_With
-           (Input   : in     Lexer_With_Input;
+           (Input   : in     With_Input;
             Context : in out Lexer_Context)
         return Gen_Tokens.Token_Array;
 
@@ -112,7 +114,7 @@ package Packrat.Lexer is
         Pad_In     : in Element;
         Pad_Out    : in Gen_Tokens.Token;
     procedure Scan_Set_With
-           (Input   : in     Lexer_With_Input;
+           (Input   : in     With_Input;
             Context : in out Lexer_Context;
             Output  :    out Gen_Tokens.Token_Array);
 
@@ -256,55 +258,96 @@ package Packrat.Lexer is
 private
 
 
-    type Element_Array_Access is access Element_Array;
+    package Token_Vectors is new Ada.Containers.Vectors
+       (Index_Type   => Positive,
+        Element_Type => Gen_Tokens.Token,
+        "="          => Gen_Tokens."=");
+
+
+
+
+    type Element_Array_Access is access all Element_Array;
 
     Empty_Array : Element_Array (1 .. 0);
 
 
 
 
-    type Combinator_Result is new Ada.Finalization.Controlled with record
-        Length : Natural;
+    package Label_Vectors is new Ada.Containers.Vectors
+       (Index_Type   => Positive,
+        Element_Type => Label_Enum);
+
+
+
+
+    package Label_Sets is new Ada.Containers.Ordered_Sets
+       (Element_Type => Label_Enum);
+
+
+
+
+    type Combinator_Result is record
+        Finish : Natural;
         Status : Result_Status;
-        Value  : Element_Array_Access;
     end record;
 
-    overriding procedure Initialize
-           (This : in out Combinator_Result);
+    Empty_Fail : constant Combinator_Result :=
+       (Finish => 0,
+        Status => Failure);
 
-    overriding procedure Adjust
-           (This : in out Combinator_Result);
 
-    overriding procedure Finalize
-           (This : in out Combinator_Result);
 
-    Empty_Fail : constant Combinator_Result :=
-       (Ada.Finalization.Controlled with
-        Length => 0,
-        Status => Failure,
-        Value  => null);
 
+    type Component_Result is (Component_Failure, Component_Success);
 
 
 
-    package Token_Vectors is new Ada.Containers.Vectors
-       (Index_Type   => Positive,
-        Element_Type => Gen_Tokens.Token,
-        "="          => Gen_Tokens."=");
 
     type Lexer_Context is new Ada.Finalization.Controlled with record
-        Result_So_Far : Token_Vectors.Vector;
-        Position      : Positive;
-        Status        : Result_Status;
-        Pass_Forward  : Element_Array_Access;
+        Result_So_Far    : Token_Vectors.Vector;
+        Position         : Positive;
+        Offset           : Natural;
+        Status           : Result_Status;
+        Pass_Forward     : Element_Array_Access;
+        Empty_Labels     : Label_Sets.Set;
+        Error_Labels     : Label_Vectors.Vector;
+        Allow_Incomplete : Boolean;
     end record;
 
+    overriding procedure Initialize
+           (This : in out Lexer_Context);
+
+    overriding procedure Adjust
+           (This : in out Lexer_Context);
+
+    overriding procedure Finalize
+           (This : in out Lexer_Context);
+
     Empty_Context : constant Lexer_Context :=
        (Ada.Finalization.Controlled with
-        Result_So_Far => Token_Vectors.Empty_Vector,
-        Position      => 1,
-        Status        => Success,
-        Pass_Forward  => null);
+        Result_So_Far    => Token_Vectors.Empty_Vector,
+        Position         => 1,
+        Offset           => 0,
+        Status           => Success,
+        Pass_Forward     => null,
+        Empty_Labels     => Label_Sets.Empty_Set,
+        Error_Labels     => Label_Vectors.Empty_Vector,
+        Allow_Incomplete => True);
+
+
+
+
+    type Input_Container is new Ada.Finalization.Limited_Controlled with record
+        Data    : Element_Array_Access;
+        Dealloc : Boolean;
+    end record;
+
+    overriding procedure Finalize
+           (This : in out Input_Container);
+
+    function Pass_Input
+           (Passed, Continuing : in Element_Array_Access)
+        return Input_Container;
 
 
 end Packrat.Lexer;