Natools

   type Quoted_Option is (When_Shorter, Single_Line, No_Quoted);
   type Token_Option is (Extended_Token, Standard_Token, No_Token);
   type Screen_Offset is new Natural;

   subtype Screen_Column is Screen_Offset range 1 .. Screen_Offset'Last;

   type Parameters is record
      Width         : Screen_Offset;
      Newline_At    : Entity_Separator;
      Space_At      : Entity_Separator;
      Tab_Stop      : Screen_Column;
      Indentation   : Screen_Offset;
      Indent        : Indent_Type;
      Quoted        : Quoted_Option;
      Token         : Token_Option;
      Hex_Casing    : Encodings.Hex_Casing;
      Quoted_Escape : Quoted_Escape_Type;
      Char_Encoding : Character_Encoding;
      Fallback      : Atom_Encoding;
      Newline       : Newline_Encoding;
      Width         : Screen_Offset        := 0;
      Newline_At    : Entity_Separator     := (others => (others => False));
      Space_At      : Entity_Separator     := (others => (others => False));
      Tab_Stop      : Screen_Column        := 8;                --  *
      Indentation   : Screen_Offset        := 0;
      Indent        : Indent_Type          := Spaces;           --  *
      Quoted        : Quoted_Option        := No_Quoted;
      Token         : Token_Option         := No_Token;
      Hex_Casing    : Encodings.Hex_Casing := Encodings.Upper;  --  *
      Quoted_Escape : Quoted_Escape_Type   := Hex_Escape;       --  *
      Char_Encoding : Character_Encoding   := ASCII;            --  *
      Fallback      : Atom_Encoding        := Verbatim;
      Newline       : Newline_Encoding     := LF;               --  *
   end record;
      --  Default values yield canonical encoding, though fields marked with
      --  an asterisk (*) can have any value and still be canonical.

   Canonical : constant Parameters;
   Canonical : constant Parameters := (others => <>);

   type Printer is abstract limited new Printers.Printer with private;

   procedure Write_Raw
     (Output : in out Printer;
      Data : in Ada.Streams.Stream_Element_Array)
     is abstract;

      Cursor       : Screen_Column := 1;
      Previous     : Entity;
      First        : Boolean := True;
      Indent_Level : Screen_Offset := 0;
      Need_Blank   : Boolean := False;
   end record;

   Canonical : constant Parameters :=
     (Width         => 0,
      Newline_At    => (others => (others => False)),
      Space_At      => (others => (others => False)),
      Tab_Stop      => 8,  --  unused
      Indentation   => 0,
      Indent        => Spaces,  --  unused
      Quoted        => No_Quoted,
      Token         => No_Token,
      Hex_Casing    => Encodings.Upper,  --  unused
      Quoted_Escape => Octal_Escape,  --  unused
      Char_Encoding => ASCII,  --  unused
      Fallback      => Verbatim,
      Newline       => LF);  --  unused

   type Stream_Printer (Stream : access Ada.Streams.Root_Stream_Type'Class) is
     new Printer with null record;

   overriding procedure Write_Raw
     (Output : in out Stream_Printer;
      Data : in Ada.Streams.Stream_Element_Array);

end Natools.S_Expressions.Printers.Pretty;