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.