ifTable

IfTable is a conceptual construct used in programming and data processing to implement conditional decision tables. It represents a mapping from a set of conditions to an outcome, enabling data-driven decision making. A typical ifTable consists of a collection of rows; each row contains one or more condition expressions and a corresponding result expression. A default or catch-all row may be provided for cases where none of the conditions match.

Evaluation is performed by applying the input context to each row's conditions in a predefined order, returning the first matching row's result, or in multi-match designs, aggregating results or selecting based on a rule priority. Implementations may allow explicit priority, short-circuiting rules, or cascading tables where one table feeds another.

Variants and representations include decision tables, rule tables, and lookup tables. They can be expressed as in-code constructs, or stored in external formats such as CSV or JSON, enabling data-driven configuration without hard-coded conditionals. Some systems combine ifTable with a rule engine, supporting complex predicates, actions, and side effects.

Applications include business rule processing, data validation, pricing and discount logic, routing decisions, and feature-flag evaluation. Research and practice emphasize clarity of conditions, avoidance of ambiguity, and explicit handling of missing or conflicting data.

Design considerations include performance, maintainability, documentation of rule order, and testing for coverage and edge cases. See also decision table, rule engine, and lookup table.