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Conditionally excluding menu options from the menu

I wrote a Perl module that can create and manage simple menus, but now I need to figure out how to conditionally hide menu selections when I don't want them to be available.

For example, how can I hide "Choice2"in $menu1if a specific condition is met?

This question is a continuation of one of my other questions: How can I create a simple menu in Perl?

I have made considerable progress since I started this, but it looks like I got into a roadblock.

The menu module is as follows:

# Menu.pm

#!/usr/bin/perl

package Menu;

use strict;
use warnings;

# Menu constructor
sub new {

    # Unpack input arguments
    my $class       = shift;
    my (%args)      = @_;
    my $title       = $args{title};
    my $choices_ref = $args{choices};
    my $noexit      = $args{noexit};

    # Bless the menu object
    my $self = bless {
        title   => $title,
        choices => $choices_ref,
        noexit  => $noexit,
    }, $class;

    return $self;
}

# Print the menu
sub print {

    # Unpack input arguments
    my $self    = shift;
    my $title   =   $self->{title  };
    my @choices = @{$self->{choices}};
    my $noexit  =   $self->{noexit };

    # Print menu
    for (;;) {

        # Clear the screen
        system 'cls';

        # Print menu title
        print "========================================\n";
        print "    $title\n";
        print "========================================\n";

        # Print menu options
        my $index = 0;
        for my $choice(@choices) {
            printf "%2d. %s\n", ++$index, $choice->{text};
        }
        printf "%2d. %s\n", '0', 'Exit' unless $noexit;

        print "\n?: ";

        # Get user input
        chomp (my $input = <STDIN>);

        print "\n";

        # Process input
        if ($input =~ m/\d+/ && $input >= 1 && $input <= $index) {
            return $choices[$input - 1]{code}->();
        } elsif ($input =~ m/\d+/ && !$input && !$noexit) {
            print "Exiting . . .\n";
            exit 0;
        } else {
            print "Invalid input.\n\n";
            system 'pause';
        }
    }
}

1;

Here is an example of using the module:

# test.pl

#!/usr/bin/perl

use strict;
use warnings;

use Menu;

my $menu1;
my $menu2;

# define menu1 choices
my @menu1_choices = (
    { text => 'Choice1',
      code => sub { print "I did something!\n"; }},
    { text => 'Choice2',
      code => sub { print "I did something else!\n"; }},
    { text => 'Go to Menu2',
      code => sub { $menu2->print(); }},
);

# define menu2 choices
my @menu2_choices = (
    { text => 'Choice1',
      code => sub { print "I did something in menu 2!\n"; }},
    { text => 'Choice2',
      code => sub { print "I did something else in menu 2!\n"; }},
    { text => 'Go to Menu1',
      code => sub { $menu1->print(); }},
);

# Build menu1
$menu1 = Menu->new(
    title   => 'Menu1',
    choices => \@menu1_choices,
);

# Build menu2
$menu2 = Menu->new(
    title   => 'Menu2',
    choices => \@menu2_choices,
);

# Print menu1
$menu1->print();

Since the menu selection is defined as an array of hashes, I'm not sure how I can conditionally exclude certain parameters if I do not want them to be displayed.

Is there an easy way to do this?

+4
4

, , ! , , .

:

# test.pl

#!/usr/bin/perl

# Always use these
use strict;
use warnings;

# Other use statements
use Menu;

# Create a menu object
my $menu = Menu->new();

# Add a menu item
$menu->add(
    'Test'  => sub { print "This is a test\n";  system 'pause'; },
    'Test2' => sub { print "This is a test2\n"; system 'pause'; },
    'Test3' => sub { print "This is a test3\n"; system 'pause'; },
);

# Disable a menu item
$menu->disable('Test2');
$menu->print();

# Enable a menu item
$menu->enable('Test2');
$menu->print();

, . / .

# Menu.pm

#!/usr/bin/perl

package Menu;

# Always use these
use strict;
use warnings;

# Other use statements
use Carp;
use Menu::Item;

# Menu constructor
sub new {

    # Unpack input arguments
    my ($class, $title) = @_;

    # Define a default title
    if (!defined $title) {
        $title = 'MENU';
    }

    # Bless the Menu object
    my $self = bless {
        _title => $title,
        _items => [],
    }, $class;

    return $self;
}

# Title accessor method
sub title {
    my ($self, $title) = @_;
    $self->{_title} = $title if defined $title;
    return $self->{_title};
}

# Items accessor method
sub items {
    my ($self, $items) = @_;
    $self->{_items} = $items if defined $items;
    return $self->{_items};
}

# Add item(s) to the menu
sub add {

    # Unpack input arguments
    my ($self, @add) = @_;
    croak 'add() requires name-action pairs' unless @add % 2 == 0;

    # Add new items
    while (@add) {
        my ($name, $action) = splice @add, 0, 2;

        # If the item already exists, remove it
        for my $index(0 .. $#{$self->{_items}}) {
            if ($name eq $self->{_items}->[$index]->name()) {
                splice @{$self->{_items}}, $index, 1;
            }
        }

        # Add the item to the end of the menu
        my $item = Menu::Item->new($name, $action);
        push @{$self->{_items}}, $item;
    }

    return 0;
}

# Remove item(s) from the menu
sub remove {

    # Unpack input arguments
    my ($self, @remove) = @_;

    # Remove items
    for my $name(@remove) {

        # If the item exists, remove it
        for my $index(0 .. $#{$self->{_items}}) {
            if ($name eq $self->{_items}->[$index]->name()) {
                splice @{$self->{_items}}, $index, 1;
            }
        }
    }

    return 0;
}

# Disable item(s)
sub disable {

    # Unpack input arguments
    my ($self, @disable) = @_;

    # Disable items
    for my $name(@disable) {

        # If the item exists, disable it
        for my $index(0 .. $#{$self->{_items}}) {
            if ($name eq $self->{_items}->[$index]->name()) {
                $self->{_items}->[$index]->active(0);
            }
        }
    }

    return 0;
}

# Enable item(s)
sub enable {

    # Unpack input arguments
    my ($self, @enable) = @_;

    # Disable items
    for my $name(@enable) {

        # If the item exists, enable it
        for my $index(0 .. $#{$self->{_items}}) {
            if ($name eq $self->{_items}->[$index]->name()) {
                $self->{_items}->[$index]->active(1);
            }
        }
    }
}

# Print the menu
sub print {

    # Unpack input arguments
    my ($self) = @_;

    # Print the menu
    for (;;) {
        system 'cls';

        # Print the title
        print "========================================\n";
        print "    $self->{_title}\n";
        print "========================================\n";

        # Print menu items
        for my $index(0 .. $#{$self->{_items}}) {
            my $name   = $self->{_items}->[$index]->name();
            my $active = $self->{_items}->[$index]->active();
            if ($active) {
                printf "%2d. %s\n", $index + 1, $name;
            } else {
                print "\n";
            }
        }
        printf "%2d. %s\n", 0, 'Exit';

        # Get user input
        print "\n?: ";
        chomp (my $input = <STDIN>);

        # Process user input
        if ($input =~ m/\d+/ && $input > 0 && $input <= scalar @{$self->{_items}}) {
            my $action = $self->{_items}->[$input - 1]->action();
            my $active = $self->{_items}->[$input - 1]->active();
            if ($active) {
                print "\n";
                return $action->();
            }
        } elsif ($input =~ m/\d+/ && $input == 0) {
            return 0;
        }

        # Deal with invalid input
        print "\nInvalid input.\n\n";
        system 'pause';
    }
}

1;

, Menu:: Item, . ( , "", ).

# Item.pm

#!/usr/bin/perl

package Menu::Item;

# Always use these
use strict;
use warnings;

# Menu::Item constructor
sub new {

    # Unpack input arguments
    my ($class, $name, $action) = @_;

    # Bless the Menu::Item object
    my $self = bless {
        _name   => $name,
        _action => $action,
        _active => 1,
    }, $class;

    return $self;
}

# Name accessor method
sub name {
    my ($self, $name) = @_;
    $self->{_name} = $name if defined $name;
    return $self->{_name};
}

# Action accessor method
sub action {
    my ($self, $action) = @_;
    $self->{_action} = $action if defined $action;
    return $self->{_action};
}

# Active accessor method
sub active {
    my ($self, $active) = @_;
    $self->{_active} = $active if defined $active;
    return $self->{_active};
}

1;

.

.:)

0

MenuItem, , , . . , "disabled" .

, "print" .

#!/usr/bin/perl

package MenuItem;

use strict;
use warnings;

sub new {
    # Unpack input arguments
    my $class       = shift;
    my (%args)      = @_;
    my $text        = $args{text};
    my $code        = $args{code};
    my $disabled        = $args{disabled};

    # Bless the menu object
    my $self = bless {
        text   => $text,
        code   => $code,
        disabled => $disabled,
    }, $class;

    return $self;
}

1;

package Menu;

use strict;
use warnings;

# Menu constructor
sub new {

    # Unpack input arguments
    my $class       = shift;
    my (%args)      = @_;
    my $title       = $args{title};
    my $choices_ref = $args{choices};
    my $noexit      = $args{noexit};

    # Bless the menu object
    my $self = bless {
        title   => $title,
        choices => $choices_ref,
        noexit  => $noexit,
    }, $class;

    return $self;
}

# Print the menu
sub print {

    # Unpack input arguments
    my $self    = shift;
    my $title   =   $self->{title  };
    my @choices = @{$self->{choices}};
    my $noexit  =   $self->{noexit };

    # Print menu
    for (;;) {

        # Clear the screen
        system 'cls';

        # Print menu title
        print "========================================\n";
        print "    $title\n";
        print "========================================\n";

        # Print menu options
        my $index = 0;
    my @items;
        for my $choice(@choices) {
        if ( ! $choice->{disabled} ) {
        $items[$index]=$choice;
        printf "%2d. %s\n", ++$index, $choice->{text};
        }
        }
        printf "%2d. %s\n", '0', 'Exit' unless $noexit;

        print "\n?: ";

        # Get user input
        chomp (my $input = <STDIN>);

        print "\n";

        # Process input
        if ($input =~ m/\d+/ && $input >= 1 && $input <= $index) {
            return $items[$input - 1]->{code}->();
        } elsif ($input =~ m/\d+/ && !$input && !$noexit) {
            print "Exiting . . .\n";
            exit 0;
        } else {
            print "Invalid input.\n\n";
            system 'pause';
        }
    }
}

1;

use strict;
use warnings;

#use Menu;

my $menu1;
my $menu2;

# define menu1 choices
my @menu1_choices = (
    MenuItem->new(text => 'Choice1',
          code => sub { print "I did something!\n"; }),
    MenuItem->new(text => 'Choice2',
          code => sub { print "I did something else!\n"; },
          disabled => 1),
    MenuItem->new(text => 'Go to Menu2',
          code => sub { $menu2->print(); }),
);

# define menu2 choices
my @menu2_choices = (
    MenuItem->new(text => 'Choice1',
          code => sub { print "I did something in menu 2!\n"; }),
    MenuItem->new(text => 'Choice2',
          code => sub { print "I did something else in menu 2!\n"; }),
    MenuItem->new(text => 'Go to Menu1',
          code => sub { $menu1->print(); }),
);

# Build menu1
$menu1 = Menu->new(
    title   => 'Menu1',
    choices => \@menu1_choices,
);

# Build menu2
$menu2 = Menu->new(
    title   => 'Menu2',
    choices => \@menu2_choices,
);

# Print menu1
$menu1->print();
+2

, . , : ", , , ?"

grep :

my $menu2 = Menu->new(
    title   => 'Menu2',
    choices => [grep { $_->{text} ne 'Choice2' } @menu2_choices],
);
+1

Suppose you have a blacklist as a parameter. Of course, you can put this somewhere else, for example. as an attribute of an object.

Just check each of them on the blacklist. Or remove them directly from the selection array.

sub print {
  my ($self, @blacklist) = @_;
    for my $choice (@choices) {
       printf "%2d. %s\n", ++$index, $choice->{text}
         unless grep { $_ eq $choice->{text} } @blacklist;
    }
}
+1
source

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