José Alves de Castro > Games-Score-0.02 > Games::Score

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NAME ^

Games::Score - Keep track of score in games

SYNOPSIS ^

    use Games::Score;

    # these three values are the default ones, by the way
    Games::Score->default_score(0);
    Games::Score->default_step(1);
    Games::Score->step_method('inc');

    # start two players
    my $player1 = Games::Score->new();
    my $player2 = Games::Score->new();

    # set a winning condition
    Games::Score->victory_is( sub { $_[0] >= 20 } );

    # and something to do if it is achieved
    Games::Score->on_victory_do( sub { print "Won!" } );

    # give points to the players
    $player1->add(2);
    $player2->step();

    # look at section FUNCTIONS for more functionalities, such as
    Games::Score->invalidate_if( sub { $_[0] > 20 } );

DESCRIPTION ^

Games::Score can be use to keep track of several players' points in a game, regardless of the starting amount of points, winning and/or losing conditions, etc.

It provides several useful methods so that the user doesn't have to keep testing values to see if they're valid or if the player condition has changed.

FUNCTIONS ^

BASIC METHODS

new

  new();
  new(PLAYERNAME);
  new(PLAYER_NAME,PLAYER_SCORE);

Creates a new Games::Score object. Default name is "Player" and default score is 0.

  # start a player with the default points
  my $player1 = Games::Score->new();

  # start a player named "BANZAI"
  my $player2 = Games::Score->new("BANZAI");

  # start a player named "BANZAI" with 20 points
  my $player2 = Games::Score->new("BANZAI",20);

VICTORY AND DEFEAT METHODS

victory_is

  victory_is(CODE)

Allows for defining a funtion which, receiving the player's score, will return true if the player has won the game.

This function is used by has_won().

In addition, if both victory_is() and on_victory_do() are defined, as soon as the player's score changes and the victory condition (defined with victory_is()) is verified, the function defined with on_victory_do() is executed.

The function defined with victory_is() receives the score as a parameter.

  # set the winning condition to be "score is greater or equal than 20"
  Games::Score->victory_is( sub { $_[0] >= 20 } )

defeat_is

  defeat_is(CODE);

Allows for defining a funtion which, receiving the player's score, will return true if the player has lost the game.

This function is used by has_lost().

In addition, if both defeat_is() and on_defeat_do() are defined, as soon as the player's score changes and the defeat condition (defined with defeat_is()) is verified, the function defined with on_defeat_do() is executed.

The function defined with defeat_is() receives the score as a parameter.

  # set the winning condition to be "score is negative"
  Games::Score->defeat_is( sub { $_[0] < 0 } )

on_victory_do

  on_victory_do(CODE);

This method lets you define a function that will be called as soon as has_won() starts returning a true value. In other words, when the score changes and the function defined with is_victory() returns true, the function defined with on_victory_do() is called.

The function receives as parameters the score of the player and its name.

  # set a new condition for on_victory_do()
  our $game_ended;
  Games::Score->on_victory_do( sub { $game_ended = 1 } );

  # assuming this:
  my $player1 = Games::Score->new();
  Games::Score->victory_is( sub { $_[0] == 1 } );

  # the following line will trigger sub { $game_ended = 1 }
  $player1->score(1);

on_defeat_do

  on_defeat_do(CODE);

This method lets you define a function that will be called as soon as has_lost() starts returning a true value. In other words, when the score changes and the function defined with is_defeat() returns true, the function defined with on_defeat_do() is called.

The function receives as parameters the score of the player and its name.

  # set a new condition for on_defeat_do()
  our $game_ended;
  Games::Score->on_defeat_do( sub { $game_ended = 1 } );

  # assuming this:
  my $player1 = Games::Score->new();
  Games::Score->defeat_is( sub { $_[0] == -1 } );

  # the following line will trigger sub { $game_ended = 1 }
  $player1->score(-1);

has_won

  has_won();

Returns true if the function defined with victory_is() returns true;

  if ($player1->has_won()) {
    print "$player1->name() has won";
  }

has_lost

  has_lost();

Returns true if the function defined with defeat_is() returns true;

  if ($player1->has_lost()) {
    print "$player1->name() has lost";
  }

is_ok

  is_ok();

Returns true if the player hasn't won or lost.

  # keep playing until player either wins or loses
  while ($player1->is_ok()) {
    # your game code here
  }

SCORE METHODS

add

  add(NUMBER);
  add(NUMBER, NUMBER, ...);

Give X points to the player (this always increases, regardless of step_method()).

  # player1 gets 5 more points
  $player1->add(5);

  # player1 gets 2, 3 and 4 more points
  $player1->add(2,3,4);

subtract

  subtract(NUMBER);
  subtract(NUMBER, NUMBER, ...);

Take X points from the player (this always decreases, regardless of step_method()).

  # player1 loses 5 points
  $player1->subtract(5);

  # player1 loses 2, 3 and 4 more points
  $player1->subtract(2,3,4);

invalidate_if

  invalidate_if(CODE);

When the score is about to change, score doesn't change if the function defined with invalidate_if() returns true.

  # sets the condition so that negative values are not allowed
  Games::Score->invalidate_if( sub { $_[0] < 0 } );

  # here's an example of how this works:
  Games::Score->invalidate_if( sub { $_[0] < 0 } );
  my $player1 = Games::Score->new();
  $player1->score(3);
  # this line subtracts the player's score by 2
  $player1->subtract(2);
  # this one doesn't, as his score is already 1 and the result would be
  # invalid
  $player1->subtract(2);

If one is, for instance, adding several numbers to the score, no more numbers are added as soon as the score can be invalidated.

  # assuming the same configuration as before:
  Games::Score->invalidate_if( sub { $_[0] > 20 } );
  my $player1 = Games::Score->new();
  $player1->score(18);

  # the following line adds 1 point to the score, doesn't add 2 more as
  # that would take the score up do 21, and skips the rest of the
  # instruction, even though it wouldn't invalidate anything by itself
  $player1->add(1,2,1);

To remove the condition, assign it an empty function

  # assign an empty function to victory_if
  Games::Score->invalidate_if( sub { } );

step_method

  step_method();
  step_method('inc');
  step_method('dec');

Defines whether the set() method increases or decreases score; possible values are 'inc' (increase) and 'dec' (decrease). Assigning multiple values stops at the first valid one. Default value is 'inc', increase.

  # step method is inc (increase)
  Games::Score->step_method('inc');

  # step method is dec (decrease)
  Games::Score->step_method('dec');

  # check the step method
  my $step_method = Games::Score->step_method();

default_step

  default_step();
  default_step(NUMBER);

Set or check the default number of points the step() method uses. Assigning multiple values makes the last of them to be it. Default value is 1.

  # step() function now increases (or decreases, see step_method()) in
  # 2 points
  Games::Score->default_step(2);

  # check the default_step
  my $default_step = Games::Score->default_step();

step

  step();
  step(NUMBER);

The basic operation to change score. Default is "add one point"; that can be changed with default_step() and method().

  # the score from player1 steps once
  $player1->step;

  # the score from player1 steps twice
  $player1->step(2);

default_score

  default_score();
  default_score(NUMBER);

Set or check the default score with which new players start. Default is 0.

  # all players start with 301 points
  Games::Score->default_score(301);

  # check the default_score
  my $default_score = Games::Score->default_score();

priority_is

  priority_is();
  priority_is('win');
  priority_is('lose');
  priority_is('win_lose');
  priority_is('lose_win');

Get or set the priority for actions involving winning or losing.

Possible values are:

lose

If the player wins and loses at the same time, only the action for defeat is run.

win

If the player wins and loses at the same time, only the action for victory is run.

win_lose

If the player wins and loses at the same time, the action for victory is run first and than the action for defeat is run too.

lose_win

If the player wins and loses at the same time, the action for defeat is run first and than the action for victory is run too.

Default_value is 'lose'.

  # Assuming this configuration
  Games::Score->on_victory_do( sub { "You won!" } );
  Games::Score->on_defeat( sub { "You lost!" } );

  # The following line states that if the player wins and loses at the
  # same time, he loses
  Games::Score->priority_is('lose');

score

  score();
  score(NUMBER);
  score(NUMBER, NUMBER, ...);

Get or set the score of the player. Assigning multiple values goes through all of them, skipping when invalidate_if() returns true, and stopping at the last one. Default score is 0.

  # get the score of the player
  my $score = $player->score();

  # player now has 10 points
  $player->score(10);

OTHER METHODS

default_name

  default_name();
  default_name(DEFAULT_NAME);

Set or check the default name with which new players start. Default name is 'Player'.

  # all players are by default named "PLAYER"
  Games::Score->default_name("PLAYER");

  # check the default_name
  my $default_name = Games::Score->default_name();

name

  name();
  name(NEW_NAME);

Get or set the name of the player. Default name is 'Player', which can be changed with default_name().

  # get the name of the player
  my $name = $player->name();

  # player is now named "WARRIOR"
  $player->name("WARRIOR");

REGARDING DRAWS ^

Please note the following: if you happen to have two players, change the score for both of them and both of them get in the same situation (victory, for instance), one of them is going to have his on_victory_do() function (if defined) run before the other one.

Always consider the possibility of draws in your game with disregard to Games::Score (at least for now).

EXAMPLES ^

START AT 0, WIN AT 20 OR MORE

Example of a game where users start with 0 points and win as soon as they get more than 20 points. There is no way of losing.

  # These two lines aren't actually needed, as these are the default
  # values
  Games::Score->default_score(0);
  Games::Score->step_method('inc');

  # Set the victory condition
  Games::Score->victory_is( sub { $_[0] > 20; } );

  # Set what to do on victory
  our $game_ended = 0;
  our $message = '';
  Games::Score->on_victory_do( sub {
                                      $game_ended = 1;
                                      $message = "$_[1] has won!\n";
                                   } );

  # Start two players, "Shiribi" and "Zuncucu"
  my $player1 = Games::Score->new("Shiribi");
  my $player2 = Games::Score->new("Zuncucu");
  my @players = ($player1, $player2);

  # And have a random game
  until ($game_ended) {
    for (@players) {
      if (rand(1)) {
        $_->step();
        print "Player $_->name() scored ",
              "and now has $_->score() point(s).\n";
        last if $_->has_won();
      }
      else {
        print "Player $_->name() didn't score.\n"
      }
    }
  }

START AT 301, GO DOWN AND WIN ON 0, PRECISELY

Example of a game where users start with 301 points, always lose points instead of gaining them, and win when they reach 0 points. Getting less than 0 points invalidates the score update.

  # default score is 301, points decrease, winning on 0, negative score
  # disallowed
  Games::Score->default_score(301);
  Games::Score->step_method('dec');
  Games::Score->invalidate_if( sub { $_[0] < 0 } );
  Games::Score->victory_is( sub { $_[0] == 0 } );

AUTHOR ^

Jose Castro, <cog@cpan.org>

COPYRIGHT & LICENSE ^

Copyright 2004 Jose Castro, All Rights Reserved.

This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

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