Re^2: Not quite an OO tutorial

[Lady_Aleena]

Since GrandFather wrote the object oriented code above for me, I am more than willing to show how I would write it in functions. I let my eyes glaze over on the overdrive bit, so I don't have a functional way to do that (if there is a way, that is).

Let's start with the module:

packack Random::Things;
use strict;
use warnings;
use base 'Exporter';
our @EXPORT_OK = qw(RandDayPart RandLight RandWeather RandTense);

sub RandDayPart {
  my @randdaypart = qw(morning evening afternoon night);
  return $randdaypart[rand @randdaypart];
}

sub RandLight {
  my @randlight = qw(bright dark gloomy dazzling);
  return $randlight[rand @randlight];
}

sub RandWeather {
  my @randweather = qw(stormy windy rainy calm);
  return $randweather[rand @randweather];
}

sub RandTense {
  my @randtense = ('was', 'is', 'will be');
  return $randtense[rand @randtense];
}

1;

Now the script:

use strict;
use warnings;

use Random::Things qw(RandDayPart RandLight RandWeather RandTense);

my $random_day_part = RandDayPart;
my $random_light = RandLight;
my $random_weather = RandWeather;
my $random_tense = RandTense;

print "It $random_tense a $random_light and $random_weather $random_da
+y_part."

It may not be nice and have things like inheritance that the OO version has, but it will do the same thing in a crunch.

[james2vegas]

I would skip the duplication and the exporting of functions, something like this:



package Rand;
use strict;
use warnings;

sub _random {
    my @values = @_;
    return $values[rand @values];
}

sub day_part {
    return _random(qw(morning evening afternoon night));
}

sub light {
  return _random(qw(bright dark gloomy dazzling));
}

sub weather {
    return _random(qw(stormy windy rainy calm));
}

sub tense {
  return _random('was', 'is', 'will be');
}

1;


and the example code would look like this:

use strict;
use warnings;

use Rand;

my $random_day_part = Rand::day_part;
my $random_light = Rand::light;
my $random_weather = Rand::weather;
my $random_tense = Rand::tense;

print "It $random_tense a $random_light and $random_weather $random_da
+y_part."

[Lady_Aleena]

Until I read your post, james2vegas, I thought that the only want to get a subroutine out of a module without use base 'Exporter'; was to use objects which is why I always use base 'Exporter'. I have not seen subroutines constructed like that before. Would you please tell me what that is called (and maybe where I can find it) so that I can do more reading on it? There is more to non-object oriented programming that I don't know which may be why I am having a hard time grasping object oriented programming in the first place. Maybe the first thing I need to do is to get away from the Exporter without objects before getting into objects. I have been tied to Exporter since Lady Aleena's first working module.

[RedElk]

Lady_Aleena, my knowledge is pretty basic still, but for what it's worth I found the information here and page 9 here helpful to understand more about how the subs are working. Maybe this will be helpful to you as well.

[Anonymous Monk]

• Simple Module Tutorial
• Variables and Scoping
  • Coping with Scoping
  • Of Symbol Tables and Globs
• 1. Why it's stupid to `use a variable as a variable name'
  2. A More Direct Explanation of the Problem
  3. What if I'm Really Careful?
• :) use Data::Dump::Streamer ; Dump(\%::);

[Lady_Aleena]

I found information on the constructs that you used, james2vegas, that confused me in Exporter under "Selecting What To Export."

1. A leading underscore on a subroutine name (_someSub) is just a convention to denote subroutines that are internal and are to be used only in the module.
2. ModuleName::someSub is just another way to call a subroutine without having to export it explicitly using our @EXPORT or our @EXPORT_OK.

These things, while minor, are nice to know for my future writings. I will start adding leading underscores to my internal subroutines, since it is a great visual aid. I might also start using ModuleName::someSub when a module of mine has only one or two subroutines. Thanks for showing me these shortcuts! Cookies! :)