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This section lists all blog posts, regardless of topic.
Exercise 16: Implement SolveConditionSeptember 12, 2008
SummaryInputs:   | A rule condition with 1 or more variable tokens. |
| A hash which defines the values of zero or more variables. |
| The current token position. |
Outputs: | A list of hashes. Each hash represents a set of variable values that satisfies the condition. |
Algorithm: | Tokens are processed from left to right. |
| Non-variable tokens are skipped over. |
| Each variable which is found to exist in the variable hash should have its value substituted. |
| Each unknown variable token needs to be solved. This list of possible entities is used to permute the variable hash into N new hashes. For each hash, the function recurses. |
|  | This subroutine should not be called for relationships with two variables. |
| The output of a recurse is a list of hashes. Each of these hashes represents part of the final output of the function. |
Exercise 15: Implement SolveAssignmentVariable and SolveRelationshipVariableSeptember 12, 2008
SolveAssignmentVariable Summary | If the variable is within the path, use SolvePathVariable. Once solved, if the path is free of variables and the value is known, ensure the value matches. |
| If the variable is the value of the assignment, then simply look it up. |
SolveRelationshipVariable Summary | If there is only one variable, then use the appropriate entity's relation index to return all possibilities. |
| If there are two variables, then this subroutine should not have been called. |
Input: An assignment and a position within that assignment. Output: A list of entities. Exercise 14: Implement SolvePathVariableSeptember 11, 2008
SummaryInputs: | A parent entity, which might be null. |
| A parent relation type which describes the mandatory relationship between the parent entity and the variable entity that is being solved for. |
| A child entity, which might be null. |
| A child relation type which describes the mandatory relationship between the the variable entity that is being solved for and the child entity. |
Outputs: All entities that satisfy the conditions. To accomplish this, new indices and their respective look up functions will need to be added to the Entity and Brain classes: New index: Given an entity Y and relation type R, what entities X satisfy the relationship X R Y? New lookup functions: | 1. | GetInverseHasList: Given an entity X, which entities have a has_a relationship with X? |
| 2. | GetInverseIsAList: Given an entity X, which entities have a is_a relationship with X? (Actually, it appears that this one might not be needed) |
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