Cells lets you define selected slots of CLOS instances as if they were cells in a spreadsheet. As with spreadsheet cells, a cell slot (cell, for short) can have bound to it a literal value or a formula.
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If a rule dynamically accesses another cell, a dependency is automatically recorded. Each time a rule runs the dependencies are re-evaluated, so a branching rule may depend on different cells from time to time.
When a cell changes, all cells dependent on that cell are recalculated. This eager evaluation cascades recusively from one used value to its multiple users, recursively through the dependency graph...
