regex-cache

This crate provides a library for caching or lazily creating regular expressions.

Lazy regular expressions are backed by a OnceMutex, while the regular expression cache is backed by a Least Recently Used cache.

Why not lazy_static!?

lazy_static! is great but it's only usable when you know what your regular expression is.

In some cases you're loading an insane number of regular expressions (looking at you libphonenumber) that you might eventually use but don't actually want to store as String since that makes you lose type information and ease of use.

When to use LazyRegex

When you have many regular expressions you don't want to use instantly and don't care about delaying the regular expression compilation.

When to use RegexCache

When you want to limit the number of active regular expressions, the RegexCache only keeps around a specified number of actively used regular expressions.

Since it's an LRU cache having a small limit and using different regular expressions every time ends up wasting memory and time for nothing.