strat has asked for the wisdom of the Perl Monks concerning the following question:
Dear monks,
I wrote a little script called excelPerl.pl (like xlsPerl, but using Win32::OLE for getting read/write-access to the excel file) which tries to do to an excel file what perl -ane does for a text file, and to keep the interface as similar as possible, I also use the array @F for accessing the cells of one row. Since I want to save changes of elements of @F into the excel file, I decided to use a tied array.
The program works fine, but I couldn't find a clean way to return the tied array from a subroutine so I can use it as array (and not as array reference)
Here a minimal code example returning as arrayref which works:
my $array = TieVariable(); ### Pos1 print "### Initialization finished\n"; for (0..$#$array) { print "$_: $array->[$_]\n"; } # for $array->[6] = 1000; untie $array; # ------------------------------------------------------------ sub TieVariable { tie my @array, 'Tie::Excel::Array'; $array[$_] = 5 * $_ for 0..5; return \@array; ### Pos2 } # TieVariable # ============================================================ package Tie::Excel::Array; sub TIEARRAY { my( $class ) = @_; return bless [], $class; } # TIEARRAY # ------------------------------------------------------------ sub STORE { my( $self, $index, $value ) = @_; warn "STORE: \$self->[$index] = $value;\n"; $self->[$index] = $value; } # STORE # ------------------------------------------------------------ sub FETCH { my( $self, $index ) = @_; warn "FETCH: \$self->[$index] = $self->[$index];\n"; return $self->[$index]; } # STORE # ------------------------------------------------------------ sub FETCHSIZE { my( $self ) = @_; return $#$self; } # FETCHSIZE # ------------------------------------------------------------ sub UNTIE { my( $self ) = @_; warn "UNTIE\n"; } # UNTIE # ...
Using array
If I just change POS1 to my @array = TieVariable(); and POS2 to return @array; to be able to work with an array in my main program, the array looses its binding, and the change in $array->[6] = 1000; can't be written to the excel file.
Using a global variable
If I use @F as global variable and fill it, it would work; but then I have to know the name of the global variable in the subroutine, and can only use one @F.
Working with an alias
using a package variable and working with something like: our @F; *F = \@MyPackage::Array1;, but then I have to know the variable's name in my main program, and can only use one @MyPackage::Array1
Move the tie into the main program
I like this solution best, but then in the main program you have to know you are working with a tied array
Writing a sourcefilter or similar
Working with the arrayref-solution and writing a source filter which converts accesses to $F[0] to $F->[0] looks much to complicated.
Do you know another solution how I can do it?
The main program of excelPerl.pl should look something like:
# ... parsing parameters: $filename, $perlCode, $separator, ... my $xls = XlsPerl->new( ... parameters ... ); while( my @F = $xls->getNextRowData ) { ### POS 1 local $_ = join( $separator, @F ); eval $perlCode; die $@ if $@; } # while
Best regards,
perl -e "s>>*F>e=>y)\*martinF)stronat)=>print,print v8.8.8.32.11.32"
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Replies are listed 'Best First'. | |
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Re: returning tied array
by nobull (Friar) on Jan 07, 2007 at 13:54 UTC | |
by strat (Canon) on Jan 08, 2007 at 09:33 UTC | |
Re: returning tied array
by nobull (Friar) on Jan 07, 2007 at 14:00 UTC | |
Re: returning tied array
by ysth (Canon) on Jan 07, 2007 at 18:57 UTC | |
by WiseGuru (Initiate) on Jan 08, 2007 at 00:11 UTC | |
by AK108 (Friar) on Jan 08, 2007 at 02:36 UTC | |
by chromatic (Archbishop) on Jan 08, 2007 at 04:52 UTC | |
by AK108 (Friar) on Jan 08, 2007 at 13:57 UTC | |
Re: returning tied array
by diotalevi (Canon) on Jan 08, 2007 at 16:25 UTC |