RemoveAllPredicateT

RemoveAllPredicateT is a naming convention used in generic programming to denote a predicate type that selects elements for removal from a container. It represents a callable that tests elements and signals which items should be eliminated during a removal operation. The concept is commonly encountered in template code and is not tied to a single standard library type; its exact form can vary by project.

In practice, RemoveAllPredicateT is a boolean-valued function of an element of type T. Given an element x, the predicate returns true if x should be removed and false if it should be kept. This aligns with the erase-remove idiom used in many languages and libraries, where a removal algorithm identifies elements to drop by applying the predicate, and a subsequent erase operation truncates the container to exclude those elements.

Typical usage involves passing a predicate to a removal algorithm, such as a remove_if-style routine. For example, a code pattern may define RemoveAllPredicateT<T> as a function object or function wrapper, then apply it to a container like a vector: v.erase(std::remove_if(v.begin(), v.end(), pred), v.end()); Here pred is an instance of RemoveAllPredicateT<T> and returns true for elements slated for removal.

Design considerations include ensuring the predicate is lightweight to copy, thread-safe if used concurrently, and efficiently evaluable. Predicates can be stateless lambdas, function objects, or std::function wrappers, with the exact type depending on performance and flexibility needs. Variants of the name (such as RemoveIfPredicateT) may appear in other codebases. See also: erase-remove idiom, remove_if, predicates.