I have a hash %h
which I would like to save as YAML.
#!/usr/bin/perl
use warnings;
use strict;
my %h = ();
# -----
use YAML::Syck;
my $y = YAML::Syck::LoadFile('have_seen.yaml');
$y->%h ???
my $yaml = YAML::Syck::Dump($y);
$yaml::Syck::ImplicitUnicode = 1;
open F, ">have_seen.yaml" or die $!;
print F $yaml . "---\n";
close F;
But it seams like a chicken and egg problem.
How do I write the yaml file for the first time, so it can be read?
Update: Based on the accepted answer was the solution
#!/usr/bin/perl
use warnings;
use strict;
use YAML::Syck;
use Data::Dumper;
my $first_time = 1;
if ($first_time) {
my %h = ("1" => 2);
open F, '>', 'seen.yaml';
print F YAML::Syck::Dump(\%h);
close F;
} else {
my $h = YAML::Syck::LoadFile('seen.yaml');
$h->{"3"} = 4;
print Dumper $h;
my $yaml = YAML::Syck::Dump($h);
$yaml::Syck::ImplicitUnicode = 1;
open F, ">seen.yaml" or die $!;
print F $yaml . "---\n";
close F;
}
Use Dump
to convert an arbitrary object to a YAML-encoded string, then print that string to a file.
$h{foo} = "bar";
$h{"answer to life, the universe, and everything"} = 42;
open F, '>', 'have_seen.yaml';
print F YAML::Syck::Dump( \%h );
close F;