Define a function/subroutine inside a derived type

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Fortran has type-bound procedures, but the procedures are defined outside the definition of the type, as illustrated at the Fortran Wiki:

module class_Circle
  implicit none
  private
  real :: pi = 3.1415926535897931d0 ! Class-wide private constant
  type, public :: Circle
     real :: radius
   contains
     procedure :: area => circle_area
     procedure :: print => circle_print
  end type Circle
contains
  function circle_area(this) result(area)
    class(Circle), intent(in) :: this
    real :: area
    area = pi * this%radius**2
  end function circle_area

  subroutine circle_print(this)
    class(Circle), intent(in) :: this
    real :: area
    area = this%area()  ! Call the type-bound function
    print *, 'Circle: r = ', this%radius, ' area = ', area
  end subroutine circle_print
end module class_Circle
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