memo

Used as a more flexible alternative to Clojure's core `memoization` function. Memoized functions built using `memo` will respond to the core.memo manipulable memoization utilities. As a nice bonus, you can use `memo` in place of `memoize` without any additional changes, with the added guarantee that the memoized function will only be called once for a given sequence of arguments (`memoize` can call the function multiple times when concurrent calls are made with the same sequence of arguments). The default way to use this function is to simply supply a function that will be memoized. Additionally, you may also supply a map of the form `'{[42] 42, [108] 108}` where keys are a vector mapping expected argument values to arity positions. The map values are the return values of the memoized function. If the supplied function has metadata containing an `:clojure.core.memoize/args-fn` key, the value is assumed to be a function that should be applied to the arguments to produce a subset or transformed sequence of arguments that are used for the key in the cache (the full, original arguments will still be used to call the function). This allows you to memoize functions where one or more arguments are irrelevant for memoization, such as the `clojure.java.jdbc` functions, whose first argument may include a (mutable) JDBC `Connection` object: (memo/memo (with-meta jdbc/execute! {::memo/args-fn rest})) You can access the memoization cache directly via the `:clojure.core.memoize/cache` key on the memoized function's metadata. However, it is advised to use the core.memo primitives instead as implementation details may change over time.