subroutinenext_tokenprivate

subroutine next_token(c, s)
    type(fypp_t), intent(inout) :: c    !! the state
    type(scan_t), intent(inout) :: s    !! the expression
    integer :: n, start
    character :: ch

    n = len(s%text)
    do while (s%pos <= n)
        ch = s%text(s%pos:s%pos)
        if (ch == '#') then
            do while (s%pos <= n)
                if (s%text(s%pos:s%pos) == NL) exit
                s%pos = s%pos + 1
            end do
        else if (is_blank(ch) .or. ch == NL) then
            s%pos = s%pos + 1
        else
            exit
        end if
    end do
    s%word = ''
    if (s%pos > n) then
        s%kind = T_END
        return
    end if
    ch = s%text(s%pos:s%pos)
    start = s%pos
    if (ch == '"' .or. ch == "'") then
        s%kind = T_STR
        call read_string(c, s)
    else if ((ch == 'f' .or. ch == 'F') .and. s%pos < n) then
        if (s%text(s%pos + 1:s%pos + 1) == '"' .or. s%text(s%pos + 1:s%pos + 1) == "'") then
            s%pos = s%pos + 1
            s%kind = T_FSTR
            call read_string(c, s)
        else
            call read_name(s)
        end if
    else if (starts_name(ch)) then
        call read_name(s)
    else if (is_digit(ch)) then
        s%kind = T_INT
        s%number = 0
        do while (s%pos <= n)
            if (.not. is_digit(s%text(s%pos:s%pos))) exit
            s%number = 10*s%number + iachar(s%text(s%pos:s%pos)) - iachar('0')
            s%pos = s%pos + 1
        end do
    else
        s%kind = T_OP
        s%pos = s%pos + 1
        if (s%pos <= n) then
            if (s%text(s%pos:s%pos) == '=' .and. index('=!<>', ch) > 0) s%pos = s%pos + 1
        end if
        s%word = s%text(start:s%pos - 1)
    end if
end subroutine next_token