str_a_R4P Function

   pure function str_a_R4P(n, no_sign, separator, delimiters, compact) result(str)
   !< Convert real array to string.
   !<
   !<```fortran
   !< use penf
   !< print "(A)", str(n=[1._R4P, -2._R4P])
   !<```
   !=> +0.100000E+01,-0.200000E+01 <<<
   !<
   !<```fortran
   !< use penf
   !< print "(A)", str(n=[1._R4P, 2._R4P], no_sign=.true.)
   !<```
   !=> 0.100000E+01,0.200000E+01 <<<
   !<
   !<```fortran
   !< use penf
   !< print "(A)", str(n=[1._R4P, -2._R4P], separator='|')
   !<```
   !=> +0.100000E+01|-0.200000E+01 <<<
   !<
   !<```fortran
   !< use penf
   !< print "(A)", str(n=[1._R4P, -2._R4P], delimiters=['(', ')'])
   !<```
   !=> (+0.100000E+01,-0.200000E+01) <<<
   !<
   !<```fortran
   !< use penf
   !< print "(A)", str(n=[1._R4P, -2._R4P], compact=.true.)
   !<```
   !=> +0.1E+1,-0.2E+1 <<<
   real(R4P),    intent(in)           :: n(:)            !< Real array to be converted.
   logical,      intent(in), optional :: no_sign         !< Flag for leaving out the sign.
   character(1), intent(in), optional :: separator       !< Eventual separator of array values.
   character(*), intent(in), optional :: delimiters(1:2) !< Eventual delimiters of array values.
   logical,      intent(in), optional :: compact         !< Flag for *compacting* string encoding.
   character(len=:), allocatable      :: str             !< Returned string containing input number.
   character(DR4P)                    :: strn            !< String containing of element of input array number.
   character(len=1)                   :: sep             !< Array values separator
   integer                            :: i               !< Counter.

   str = ''
   sep = ','
   if(present(separator)) sep = separator
   do i=1,size(n)
     strn = str_R4P(no_sign=no_sign, compact=compact, n=n(i))
     str = str//sep//trim(strn)
   enddo
   str = trim(str(2:))
   if (present(delimiters)) str = delimiters(1)//str//delimiters(2)
   endfunction str_a_R4P