parse_value Subroutine

    recursive subroutine parse_value(json, unit, str, value)

    implicit none

    class(json_core),intent(inout)      :: json
    integer(IK),intent(in)              :: unit   !! file unit number
    character(kind=CK,len=*),intent(in) :: str    !! string containing JSON
                                                  !! data (only used if `unit=0`)
    type(json_value),pointer            :: value  !! JSON data that is extracted

    logical(LK)              :: eof !! end-of-file flag
    character(kind=CK,len=1) :: c   !! character read from file
                                    !! (or string) by [[pop_char]]
#if defined __GFORTRAN__
    character(kind=CK,len=:),allocatable :: tmp  !! this is a work-around for a bug
                                                 !! in the gfortran 4.9 compiler.
#endif

    if (.not. json%exception_thrown) then

        !the routine is being called incorrectly.
        if (.not. associated(value)) then
            call json%throw_exception('Error in parse_value: value pointer not associated.')
        end if

        ! pop the next non whitespace character off the file
        call json%pop_char(unit, str=str, eof=eof, skip_ws=.true., &
                            skip_comments=json%allow_comments, popped=c)

        if (eof) then
            return
        else

            select case (c)

            case (start_object)

                ! start object
                call json%to_object(value)    !allocate class
                call json%parse_object(unit, str, value)

            case (start_array)

                ! start array
                call json%to_array(value)    !allocate class
                call json%parse_array(unit, str, value)

            case (end_array)

                ! end an empty array
                call json%push_char(c)
                nullify(value)

            case (quotation_mark)

                ! string
                call json%to_string(value)    !allocate class

                select case (value%var_type)
                case (json_string)
#if defined __GFORTRAN__
                    ! write to a tmp variable because of
                    ! a bug in 4.9 gfortran compiler.
                    call json%parse_string(unit,str,tmp)
                    value%str_value = tmp
                    if (allocated(tmp))  deallocate(tmp)
#else
                    call json%parse_string(unit,str,value%str_value)
#endif
                end select

            case (CK_'t') !true_str(1:1) gfortran bug work around

                !true
                call json%parse_for_chars(unit, str, true_str(2:))
                !allocate class and set value:
                if (.not. json%exception_thrown) call json%to_logical(value,.true.)

            case (CK_'f') !false_str(1:1) gfortran bug work around

                !false
                call json%parse_for_chars(unit, str, false_str(2:))
                !allocate class and set value:
                if (.not. json%exception_thrown) call json%to_logical(value,.false.)

            case (CK_'n') !null_str(1:1) gfortran bug work around

                !null
                call json%parse_for_chars(unit, str, null_str(2:))
                if (.not. json%exception_thrown) call json%to_null(value) ! allocate class

            case(CK_'-', CK_'0': CK_'9')

                call json%push_char(c)
                call json%parse_number(unit, str, value)

            case default

                call json%throw_exception('Error in parse_value:'//&
                                     ' Unexpected character while parsing value. "'//&
                                     c//'"')

            end select
        end if

    end if

    end subroutine parse_value