closesElse

closesElse is a programming concept primarily found in functional programming languages, though its implementation and name can vary. It refers to a mechanism for handling conditional logic where a specific action is taken if a certain condition is met, and a different, default action is taken if that condition is *not* met. This is distinct from a standard "if-else" statement, where both branches are explicitly defined.

In languages that support pattern matching, closesElse is often implicitly handled. When a function or expression attempts to match against a set of patterns, and none of the provided patterns match the input, a default behavior or error can be triggered. The "closesElse" aspect is the fact that this default behavior occurs *because* all other specific possibilities were exhausted.

Consider a function designed to process different types of data. If it has patterns for integers and strings, but receives a boolean, the closesElse would be the action taken for that boolean input, assuming no explicit pattern was defined for it. This could be returning a default value, raising an exception, or simply doing nothing, depending on the language's design.

The benefit of closesElse, whether explicit or implicit, is that it ensures all possible inputs or states are accounted for. It promotes robust code by forcing developers to consider scenarios beyond the expected or explicitly defined cases, thus preventing unhandled exceptions or unexpected program behavior. While the term "closesElse" itself might not be universally used, the underlying principle of a default or fallback action when specific conditions aren't met is a fundamental aspect of structured programming and error handling.