How the Game Works
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This page describes how the game operates. If you have read the pages What is Ray's Bridge Game?, you have seen a little of how the game uses a set of rules to make a player's bids. This page will add some detail to that view. First, what is a rule?

Rules

   

The easiest way to define a rule is by example. Here are examples of each of the four types of rules. A rule can make a bid. A rule can set a value. A rule can reach a conclusion. A rule can make a comment.

A rule may simply take some action. But, more often, a rule tests the values of one or more items of information before taking the action. Every test used on a rule must evaluate to either true or false.

To execute a rule means to evaluate each test in the rule, in order, using the player's given knowledge. If all of the tests in the rule are true, then perform the action specified on the rule. If one test is false, the remaining tests are not evaluated and no action is taken.

Some of the tests that a rule may make are simple comparisons of two values. When a test compares two values, the comparison evaluates to either true or false, depending upon the two values and the nature in which they are compared. These types of information may be compared on a test.

Other tests that a rule may make are represented by a phrase in italics. The italicized phrases are references to assessments, which will be discussed further below. Assessments, like simple comparisons, evaluate to either true or false.

Groups of Rules

   

A set of rules is some number of individual rules organized into a bidding system. To organize a set of rules, the rules are divided into groups. There are three different types of groups - bidding rule groups, assessments and selectors.

When rules are placed into groups, rules that make identical tests may be combined. The game's editor automatically combines rules for you and places them exactly where you specify.

Bidding Rule Groups
   

A bidding rule group, usually just called a rule group, may contain rules which make a bid, set a value or make a comment. A rule group may not contain a rule that reaches a conclusion.

In some ways, a rule group may be thought of as a chapter or sub-chapter in a book on bidding. It contains all of the reasoning required to handle the player's current bidding situation.

When a player bids, the game selects the first rule group in the set which matches the player's current bidding situation. To select a rule group which matches the player's current bidding situation, the game uses the rule set's selectors. Selectors are described below.

After selecting the proper rule group, the game executes each rule in the group until a successful bid is found or until all of the rules have been executed. If no bid is made by the rule group, the player makes a default pass.

Here are some examples of rule groups from the set of rules that comes with the game -
opening the bidding  -  responding to a 1 in-a-suit opening  -  bidder's 2nd bid showed a new suit  -  you supported responder's 1st suit

Assessments
   

An assessment is a group of rules that can be used as a test in another rule. An assessment may contain rules which reach a conclusion, set a value or make a comment. An assessment may not contain a rule that makes a bid.

When an assessment is used as a test, the rules in the assessment are executed and the assessment reaches a conclusion of true or false. The conclusion of the assessment is then used to answer the test in the calling rule.

Assessments may be tested to be true or false. An assessment's conclusions may be true or false. Assessments may set a value in conjunction with reaching a conclusion.

Here are some examples of assessments from the set of rules that comes with the game -
your hand is suitable for notrump  -  you have a suit to open the bidding  -  you can rebid your 1st suit  -  you opened the bidding

Selectors
   

A selector is an assessment with the exact same name, except for perhaps case, as some bidding rule group in the same rule set. A selector is used to determine whether its associated rule group matches a player's current bidding situation.

On a player's turn to bid, the game takes each rule group in the order it is listed in the rule set and executes the rule group's selector. If a true conclusion is found, that rule group matches the player's current bidding situation. The game will use that rule group to make the player's bid.

Selectors are restricted in the types of information that may be used on tests. A selector may only use public knowledge. A selector may not use a player's private knowledge. This allows any player to determine which group of rules another player used to make their bid.

Here are some rule groups with their associated selector in parentheses from the set of rules that comes with the game -
opening the bidding (selector)  -  responding to a 1 in-a-suit opening (selector)  -  answering a Stayman request (selector)

The Meaning of a Bid

   

Every bid carries information about the bidder's strength, suit length or cards. The bid gathered this meaning from the tests bidder made traversing the path through the rules to their bid. Bidder's partner may retrieve this information by working backward through the rules from the bid.

To extract information from their partner's bid, a player uses the game's bid review process. While using this process the player uses only the bid and their own current knowledge. The game never allows one player to peek at another player's cards.

After a player bids, the player's partner reviews the bid. First, the reviewer looks for the selector used by bidder by executing the selectors from the bidder's point of view. To ensure that the reviewer can unequivocally locate the correct selector, selectors may use only public information.

When the reviewer has located the rule group used by bidder, the reviewer executes the group from the bidder's point of view. Using only the bid and their own current knowledge, the reviewer identifies the possible paths through the group that could have been used to make this bid.

Finally, the reviewer gathers information from those possible paths. This information is now available for the reviewer to test. It is also available for the bidder to test. For more about reviewing a bid, see Reviewing a bid.

The Strength of a Hand

   

There are many ways to judge the strength of a hand. The game provides several built-in methods which assign a number value to a hand based upon lengths of suits and cards held. To understand more about those built-in methods and also how to add new methods, see Counting Points.

Additional Features

   
Editor
   

The game has a built-in editor for reading and modifying a set of rules. For more information about the editor, see Editing the Rules. This document is old but you can still get the basics of the editor from it.

Tracing
   

To understand exactly how a player makes their bid, the game allows you to watch as the rules are executed during any player's turn. For more information, see Tracing a bid or Tracing the Rules.

To understand exactly how a player reviews their partner's bid, the game allows you to examine the results of the bid review process during any player's turn. For more information, see Reviewing a bid.

Batch Bidding
   

To document the way a set of rules bids, you may create several hand files, each containing many hands. All of the hands in a file can be bid at one time and the results of the bidding saved to file. Click on the "Batch Bid a Hand File" sub-item under the "Hands" menu bar item.