gnatmake error I don't understand

[agent@drrob1.com]

I typed the following code from a recent issue of Linux Format

texthabits.ads
with Ada.Text_IO, Ada.Strings.Unbounded,
Ada.Strings.Unbounded.Text_IO, Ada.Integer_Text_IO;
use  Ada.Text_IO, Ada.Strings.Unbounded,
Ada.Strings.Unbounded.Text_IO, Ada.Integer_Text_IO;

-- REVISION HISTORY
-- ================
-- 31 Mar 14 -- Extracted from LinuxFormat LXF 181 coding article

Package texthabits is

PROCEDURE CreateOrOpen (File: in out File_Type; Name: in String; Form:
in String := "");

Procedure OpenOrCreateDataFile(File : in out File_Type; Name : in
String);

Procedure ReadAndDisplayDatafile(File : in out File_Type; Name :
String);

Procedure Habits ;

END texthabits;

-----------------------------------------------------------------------------------------
texthabits.adb
with Ada.Text_IO, Ada.Strings.Unbounded,
Ada.Strings.Unbounded.Text_IO, Ada.Integer_Text_IO, Ada.Calendar,
Ada.Directories;
use  Ada.Text_IO, Ada.Strings.Unbounded,
Ada.Strings.Unbounded.Text_IO, Ada.Integer_Text_IO, Ada.Calendar,
Ada.Directories;

-- REVISION HISTORY
-- ================
-- 31 Mar 14 -- Extracted from LinuxFormat LXF 181 coding article


Package body texthabits is
  habit : Unbounded_String;
  filehandle : File_Type;
  HabitFileName : String(1..13);
  ctr : Natural := 1;

PROCEDURE CreateOrOpen (File: in out File_Type; Name: in String; Form:
in String := "") is
BEGIN
  Open(File, Append_File, Name, Form);
EXCEPTION
  WHEN Ada.Text_IO.Name_Error =>
    Create(File, Out_File, Name, Form);  -- If must create file, then
append_file does not make sense, even if desired.
END CreateOrOpen;

Procedure OpenOrCreateDataFile(File : in out File_Type; Name : in
String) is
Begin
  Open(File, Append_File, Name);
Exception
  when Ada.Text_IO.Name_Error => Create(File => File, Mode =>
Append_File, Name => Name);
End OpenOrCreateDataFile;

Procedure ReadAndDisplayDatafile(File : in out File_Type; Name :
String) is
  buffer : String(1..100);
  length : Natural;
Begin
  IF EXISTS(Name) THEN
    Open(File => File, Mode => In_File, Name => Name);
    While not End_Of_File(File => File) loop
      Get_Line(File => File, item => buffer, last => Length);
      Put_Line(buffer(1..length));
    end loop;
    Close(File);
  END IF; -- if exists 
End ReadAndDisplayDatafile;


Procedure Habits is
Begin
  HabitFileName  :=  "habitfile.txt";
  ReadAndDisplayDatafile(filehandle, HabitFileName);  -- for input. Do
nothing if file does not exist.
  OpenOrCreateDataFile(filehandle, HabitFileName);    -- for output
  LOOP
    Put(" Enter a new habit, quit or exit: ");
    habit  :=  Get_Line;
    exit when (CAP(To_STRING(Head(Habit,4))) = "QUIT") OR
(CAP(to_string(Head(Habit,4))) = "EXIT") ;
    Put_Line(filehandle,Habit);
    ctr := ctr + 1;
  END LOOP;
  Close(filehandle);
  Put(" You entered and saved ");
  Put(ctr,3);
  Put_Line(" new habits.");
End Habits;

END texthabits;
---------------------------------------------------------------------------------
texthabits.gpr
project texthabits is
  for Source_Files use ("texthabits.adb", "texthabits.ads",
"tokenizea.ads", "tokenizea.adb");
  for Source_Dirs use (".", "./**");
  for Main use ("Habits");                                            

  package Builder is
    for Default_Switches ("Ada")
        use ("-g");
  end Builder;

  package Compiler is
    for Default_Switches ("Ada")
       use ("-fstack-check",
            "-gnatVa",
            "-g",
            "-gnato",
            "-gnatf",
            "-gnatwu",
            "-gnat2012");
  end Compiler;
   
end texthabits;

------------------------------------------------------------------------------
Ubuntu 12.04  amd64 version

gnatmake -Ptexthabits

gnatmake: "Habits" is not a source of project texthabits.

I don't understand the error or what to do about it.

Thanks,
Rob Solomon