Value caching is sometimes needed. This need is often driven by the desire is to avoid calculating expensive operations such as inherently costly algorithms or I/O more often than necessary. The naive solution for this need is to perform some expensive operation once and cache the result. Therefore, whenever the same calculation is needed in the future it can be retrieved from cache more quickly than simply recalculating from scratch.
While effective for small domains, the naive caching of many expensive calculations or cyclopean results can consume available memory quickly. Therefore, the ideal situation is to expunge stored results that have expired, meant for single-use or less likely to be needed again. There are many general-purpose and domain-specific strategies for efficient cache population and eviction. The core.cache library provides implementations of common caching strategies as well as a mechanism for implementing custom strategies.
core.cache is a Clojure contrib library providing the following features:
CacheProtocol used as the base abstraction for implementing new synchronous caches
defcache macro for hooking your
CacheProtocol implementations into the Clojure associative data capabilities.
Implementations of some common caching strategies, including:
Factory functions for each existing cache type
The implementation of core.cache is based on and heavily influenced by the excellent 'Memoize done right' by Meikel Brandmeyer