#! /usr/bin/perl
use warnings;
use strict;

use Win32;          # automatically loaded with Activestate Perl
use File::Basename; # for PrintUsage
use Getopt::Long;   # for parsing program arguments
use FindBin;
use lib $FindBin::Bin;
use ExcelPerl;

$|++; # no suffering from buffering

my( $file, $perlCode );
my $worksheetNumber = 1;    # use first worksheet as default
my $headline        = 0;    # don't skip a headline as default
my $visible         = 0;    # is of no use in this version
my $colSeparator    = "\t"; # standard col separator for $_

GetOptions( 'file=s'       => \$file,
            'sheet=i'      => \$worksheetNumber,
            'headline=i'   => \$headline,
            'ane=s'        => \$perlCode,
#            'visible'      => \$visible,
            'colseparator' => \$colSeparator,
       ) or die &PrintUsage();

die &PrintUsage() unless defined $file;
$file = Win32::GetFullPathName( $file );

my $xlsPerl = ExcelPerl->new( excelFile       => $file,
                            worksheetNumber => $worksheetNumber,
                       )
    ->open;

#if( $visible ) {
$xlsPerl->excel->{Visible} = 1;
#} # if

# skip all lines until -headline if available
$xlsPerl->currentRow( $headline ) if $headline;

my @F;
while( $xlsPerl->getNextRow( \@F ) ) {

    # create an alias to @ExcelPerl::F; to be able to access it, it needs to
    # be a package variable, declared with our or use vars

    # prepare some other helpful variables
    local $. = $xlsPerl->currentRow();
    local $_ = join($colSeparator, @F ) . "\n";

    # try to eval the perl code
    eval $perlCode;
    die $@ if $@;

    @F = ();
} # while

# ------------------------------------------------------------
sub PrintUsage {

    my $bin = File::Basename::basename($0);
    die <<EOH;
$bin -sheet 1 -headline 1 -ane "print qq~\$.: \$F[0], \$F[1]\\n~" -file excelFile

try perldoc $bin for more details

EOH

} # PrintUsage
# ------------------------------------------------------------

=pod

=head1 excelPerl

You know about the perl parameters -ane? This script is a way to try to do
the same thing to Excel files.

=head1 Prerequisites

=over 1

=item Win32::OLE

=item Excel needs to be installed

=back

=head1 Description

Like perl -ane with a plaintext file, excelPerl.pl loops over an excel file
and automatically (-a) splits up the columns of one row into an array with
name @F. Since @F is an alias to a tied array, by changing one element of @F
you change the content of the excel cells.

If you need one whole line with a tailing \n, you can use the variable $_
(like perl -ne) which joins @F by the value given in the parameter
-colseparator (default: \t)

If you need to know the current line number (like $. for while), you can use
the special variable $. (big surprise).

=head1 Params:

  -file            String:  Name of excel file (full path!)
  -sheetnumber     Integer: which sheet shell I read (1..n, default: 1)
  -headline        Integer: line number of headline (used for skipping headline)
  -ane             String:  Perl-Code to execute
  -colseparator    String:  how to join columns in $_ (default: \t)

Abbreviations of params are allowed, as long as they are unique, e.g

  excelPerl.pl -s 2 -h 1 -ane "print qq~$.: $F[0] $F[5]\n" -f c:\test.xls

=head1 Special Variables:

  $.               Row number
  @F               Array containing the values of one complete row
  $_               Row joined by -colseparator, with \n at the end

=head1 Bugs/...

This code is very, very, very experimental!

If you do changes, you better save the workbook manually, that's the
reason why the parameter -visible always is on.

=head1 SEE ALSO

I heard about XLSperl from John Allen which is a great tool. But it only
allows to read excel files and not to change them on the fly. Since I
often need this feature, I decided to write it with Win32::OLE, and it
was not difficult. But unlike XLSperl, excelPerl only runs under Windows
and needs an installed version of Excel.

You can find XLSPerl at L<http://perl.jonallen.info/projects/xlstools>

=head1 Author

Martin Fabiani L<http://www.fabiani.net/>

=cut