comment on

I'd like to thank Athanasius for picking up the slack :)

Why was the subroutine called with 6 passed as an argument. Was this just for demonstrating that not only strings but also numbers can be passed to a sub?.

:) To demonstrates that arguments can be passed and they end up in @_ ... so you can lookup @_ in perlvar and read about it :)

Its also so you can resolve the issue you had in Re^2: search and replace strings in different files in a directory (Path::Tiny), something like

#!/usr/bin/perl --
use 5.014;
use strict;
use warnings;
use Path::Tiny qw/ path /;
use POSIX();
use autodie qw/ close /;

Main( @ARGV );
exit( 0 );

sub Main {
#~     my( $infile_paths ) = @_;
    my( $infile_paths ) = 'C:\temp\test_folder\paths.txt';;
    my @paths = GetPaths( $infile_paths );
    for my $path ( @paths ){
        FormerlyMainNowReplaceXmlKids( $path );
    }
} ## end sub Main
sub GetPaths  {
    my @paths = path( shift )->lines_utf8;
    s/\s+$// for @paths; # "chomp"
    return @paths;
} ## end sub GetPaths 
sub FormerlyMainNowReplaceXmlKids {
#~     my( $directory ) = @_; ## same as shift @_ ##  same as shift
    my $directory = shift;
    my $date      = POSIX::strftime( '%Y-%m-%d', localtime );
    my $bak       = "$date.bak";
    my @xml_files = path( $directory )->children( qr/\.xml$/ );
    for my $file ( @xml_files ) {
        Replace( $file, "$file-$bak" );
    }
} ## end sub Main

sub Replace {
    my( $in, $bak ) = @_;
    
    path( $in )->move( $bak );
    
    my $infh  = path( $bak )->openr_raw;
    my $outfh = path( $in )->openrw_raw;
    
    while( <$infh> ) {
        s{&}{&amp;}g; ## will match more than what you want fix it
        s{&amp;amp;}{&amp;}g;
        s{\s>\s}{&gt;}g;
        s{\s<\s}{&lt;}g;
        print $outfh $_;
    }
    
    close $infh;
    close $outfh;
} ## end sub Replace
[download]

Or (less complete but the sub names is the idea of this idea )

#!/usr/bin/perl --
use strict;
use warnings;
use Path::Tiny qw/ path /;

Main( @ARGV );
exit( 0 );

sub Main {
    my @dirs      = DirsForDiddling( '.../paths.txt' );
    DiddleXmlChildren( $_ ) for @dirs;
} ## end sub Main

sub DirsForDiddling {
    my( $dirfile ) = @_;
    my @dirs = path( $dirfile )->lines_utf8;
    s/\s+$// for @dirs; ## no trailing whitespace
    return @dirs;
} ## end sub DirsForDiddling

sub DiddleXmlChildren {
    my( $directory , $date, $bak ) = @_;
    $date   ||= POSIX::strftime( '%Y-%m-%d', localtime );
    $bak    ||= "$date.bak";
    my @xml_files = XmlChildren( $directory );
    for my $file ( @xml_files ) {
        Diddle( $file, "$file-$bak" );
    }
} ## end sub DiddleXmlChildren

sub XmlChildren {
    return path( shift )->children( qr/\.xml$/ );
} ## end sub XmlChildren
[download]

or more fun with names

sub Main {
    my @dirs = DirsForDonuts( '.../paths.txt' );
    for my $dir( @dirs ){
        DonutXmlChildren( $dir );
    }
} ## end sub Main

sub DirsForDonuts {
    my( $dirfile ) = @_;
    my @dirs = path( $dirfile )->lines_utf8;
    s/\s+$// for @dirs; ## no trailing whitespace
    return @dirs;
} ## end sub DirsForDonuts

sub DonutXmlChildren {
    my( $directory , $date, $bak ) = @_;
    $date   ||= POSIX::strftime( '%Y-%m-%d', localtime );
    $bak    ||= "$date.bak";
    my @xml_files = XmlChildren( $directory );
    for my $file ( @xml_files ) {
        Donut( $file, "$file-$bak" );
    }
} ## end sub DonutXmlChildren

sub XmlChildren {
    return path( shift )->children( qr/\.xml$/ );
} ## end sub XmlChildren
[download]

The idea is to have many many many subroutines, and give them names that are memorable... I chose Diddle because RenameMe didn't fit for this problem, and I'm kinda tired of NotDemoMeaningfulName and NotMainMeaningfulNameYouPick is tad long :)

Athanasius is doing pretty well :)(thanks) and I'd like to add a little note on why Main/exit, its for ease of writing/debugging/maintaining/documenting the program. The program begins with Main( @ARGV ); and ends after Main completes .

In other languages like C main() is mandatory, but its not mandatory in perl, so perl will let you write interwoven stuff like

Sky( 6 );
my $confusion = 'uhoh';
sub Sky {
  ...
}
sub Fall {
...
}
Fall( 6666666666666 );
...
if( ... ){
 ...
}
...
[download]

and this is very hard to read and maintain, but folks still do it and often struggle debugging this stuff; Main/exit combination is much easier on the brain :)

You can read more about this Main/exit style convention /program template at (tye)Re: Stupid question (and see one discussion of that template at Re^2: RFC: Creating unicursal stars

If you've got more questions, I'll be back :)

In reply to Re^10: search and replace strings in different files in a directory by Anonymous Monk
in thread search and replace strings in different files in a directory by PitifulProgrammer

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