add default case and use intrinsic in use statements

Author: gha3mi

src/forcolormap_info.f90

@@ -86,7 +86,7 @@ end function get_levels
 
    !> Filter colormaps and write metadata.
    impure subroutine write(this, verbose, name, family, gradient, palette, author, license, levels, file_name, append)
-      use iso_fortran_env, only: output_unit
+      use, intrinsic :: iso_fortran_env, only: output_unit
       class(Colormaps_info), intent(in) :: this
       integer, intent(in), optional :: verbose
       character(*), intent(in), optional :: name, family, gradient, palette, author, license
@@ -211,6 +211,9 @@ impure subroutine write(this, verbose, name, family, gradient, palette, author,
             repeat(SEP2, w_levels)   //SEP1// &
             repeat(SEP2, w_colorbar) //SEP1
 
+       case default
+         ! no header
+
       end select
 
       ! data
@@ -261,6 +264,9 @@ impure subroutine write(this, verbose, name, family, gradient, palette, author,
                cell(tmp,                        w_levels)   //SEP1// &
                cell(this%colormaps(i)%colorbar, w_colorbar) //SEP1
 
+          case default
+            print *, 'Invalid verbose level: ', verbose_
+            return
          end select
       end do
 

src/forcolormap_parameters.f90

@@ -1,6 +1,6 @@
 !> Global parameters of ForColormap.
 module forcolormap_parameters
-   use iso_fortran_env, only: wp=>real64
+   use, intrinsic :: iso_fortran_env, only: wp=>real64
    implicit none
    private
    public :: wp, pi, colormap_name_length, colormap_metadata