removed assign operator and the need for UNINITIALIZED.

src/libmtime_hl.f90

@@ -53,7 +53,8 @@ MODULE mtime_hl
 
   !> NOTE / TODO:
   !
-  !  This "UNINITIALIZED" constant hints at a problem:
+  !  Why does this wrapper module *not* implement the assignment
+  !  operator? - Lenghty answer:
   !
   !    The fundamental question is: Why do our "t_datetime",
   !    "t_timedelta", "t_xxx" types need assignment operators which
@@ -81,27 +82,16 @@ MODULE mtime_hl
   !    of "t_datetime" attempts to create an mtime "datetime" pointer
   !    based on the uninitializd "tmp_b%dt".
   !
-  !    It would be better to drop the "copy assign" implementations in
-  !    libmtime_hl altogether. At least for the basic "datetime",
-  !    "timedelta", "julianday" this is possible, since the data types
-  !    do not contain data members on the heap.
-  !
-  !    But what can we do for the more complex events? - We can work
-  !    around this problem by defining "uninitialized states" which
-  !    are recognized by the assign operator. Sigh!
-  !
-  INTEGER(c_int), PARAMETER :: UNINITIALIZED = -1_c_int
 
   !> Wrapper class for "mtime" data type "datetime".
   !
   TYPE t_datetime
 
-    !private
-
-    !> wrapped datatype of the standard mtime interface
-    TYPE(datetime) :: dt = datetime(date(year=0_c_int64_t, month=UNINITIALIZED, day=0_c_int),&
-         &                             time(hour=0_c_int, minute=0_c_int, second=0_c_int, ms=0_c_int))
+     !private
 
+     !> wrapped datatype of the standard mtime interface
+     TYPE(datetime) :: dt
+     
   CONTAINS
 
     ! --- conversions
@@ -126,7 +116,6 @@ MODULE mtime_hl
 
     ! --- overloaded operators
 
-    PROCEDURE :: assign_t_datetime
     PROCEDURE :: add_timedelta                     => t_datetime_add_timedelta
     PROCEDURE :: sub_timedelta                     => t_datetime_sub_timedelta
     PROCEDURE :: sub_datetime                      => t_datetime_sub_datetime
@@ -139,7 +128,6 @@ MODULE mtime_hl
 
     PROCEDURE :: get_c_pointer                     => t_datetime_get_c_pointer
     
-    GENERIC   :: ASSIGNMENT(=)                     =>  assign_t_datetime
     GENERIC   :: OPERATOR(+)                       =>  add_timedelta
     GENERIC   :: OPERATOR(-)                       =>  sub_timedelta
     GENERIC   :: OPERATOR(-)                       =>  sub_datetime
@@ -165,10 +153,8 @@ MODULE mtime_hl
     !private
 
     !> wrapped datatype of the standard mtime interface
-    TYPE(timedelta) :: td = timedelta( flag_std_form = 0_c_int, sign = '+', year = 0_c_int64_t,   &
-         &                                month = UNINITIALIZED, day = 0_c_int, hour = 0_c_int,      &
-         &                                minute = 0_c_int, second = 0_c_int, ms = 0_c_int )
-
+     TYPE(timedelta) :: td
+     
   CONTAINS
 
     ! --- conversions
@@ -200,7 +186,6 @@ MODULE mtime_hl
     ! note: the "+", "-" operators are not well-defined for timedelta
     ! objects!
 
-    PROCEDURE :: assign_t_timedelta
     PROCEDURE :: equal_datetime            => t_timedelta_equal
     PROCEDURE :: not_equal_datetime        => t_timedelta_not_equal
     PROCEDURE :: less_than_datetime        => t_timedelta_less_than
@@ -213,7 +198,6 @@ MODULE mtime_hl
 
     PROCEDURE :: get_c_pointer             => t_timedelta_get_c_pointer
     
-    GENERIC   :: ASSIGNMENT(=)             =>  assign_t_timedelta
     GENERIC   :: OPERATOR(==)              =>  equal_datetime
     GENERIC   :: OPERATOR(/=)              =>  not_equal_datetime
     GENERIC   :: OPERATOR(<)               =>  less_than_datetime
@@ -421,24 +405,6 @@ CONTAINS
   ! datetime section:
   ! ================================================================================
 
-  ! generic assignment for constructors
-  !
-  SUBROUTINE assign_t_datetime(to, from)
-    CLASS(t_datetime), INTENT(out) :: to
-    CLASS(t_datetime), INTENT(in) :: from
-    TYPE(datetime), POINTER :: dt_tmp
-    INTEGER :: errno
-
-    ! first, check if "from" is an initialized t_datetime object:
-    IF (from%dt%date%month /= UNINITIALIZED) THEN
-      dt_tmp => newdatetime(from%dt, errno)
-      CALL handle_errno(errno, __FILE__, __LINE__)
-      to%dt = dt_tmp
-      CALL deallocatedatetime(dt_tmp)
-    ELSE
-      to%dt = from%dt
-    END IF
-  END SUBROUTINE assign_t_datetime
 
   ! constructor for a datetime string
   !
@@ -652,25 +618,6 @@ CONTAINS
   ! timedelta section:
   ! ================================================================================
 
-  ! generic assignment for constructors
-  !
-  SUBROUTINE assign_t_timedelta(to, from)
-    CLASS(t_timedelta), INTENT(out) :: to
-    CLASS(t_timedelta), INTENT(in)  :: from
-    TYPE(timedelta), POINTER        :: td_tmp
-    INTEGER                         :: errno
-
-    ! first, check if "from" is an initialized t_datetime object:
-    IF (from%td%month /= UNINITIALIZED) THEN
-      td_tmp => newTimedelta(from%td, errno)
-      CALL handle_errno(errno, __FILE__, __LINE__)
-      to%td = td_tmp
-      to%td%sign = td_tmp%sign
-      CALL deallocateTimedelta(td_tmp)
-    ELSE
-      to%td = from%td
-    END IF
-  END SUBROUTINE assign_t_timedelta
 
   ! constructor for timedelta string
   !