Crate simple_interner

A very simplistic interner based around giving out references rather than some placeholder symbol. This means that you can mostly transparently add interning into a system without requiring rewriting all of the code to work on a new Symbol type, asking the interener to concretize the symbols.

The typical use case for something like this is text processing chunks, where chunks are very likely to be repeated. For example, when parsing source code, identifiers are likely to come up multiple times. Rather than have a String allocated for every occurrence of the identifier separately, interners allow you to store Symbol. This additionally allows comparing symbols to be much quicker than comparing the full interned string.

This crate exists to give the option of using the simplest interface. For a more featureful interner, consider using a different crate, such as

crate	global	local	'static opt1	str-only	symbol size	symbols deref
simple-interner	manual2	yes	no	no	&T	yes
intaglio	no	yes	yes	yes	u32	no
internment	rc3	yes	no	no	&T	yes
lasso	no	yes	yes	yes	u8–usize	no
string-interner	no	yes	optionally	yes	u16–usize	no
string_cache	static only	rc3	buildscript	yes	u64	yes
symbol_table	yes	yes	no	yes	u32	global only
ustr	yes	no	no	yes	usize	yes

(PRs to this table are welcome!)

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1. The interner stores &'static references without copying the pointee into the store, e.g. storing Cow<'static, str> instead of Box<str>. ↩

2. At the moment, creating the Interner inside a static, using Interner::with_hasher, requires the hashbrown feature to be enabled. ↩

3. Uses reference counting to collect globally unused symbols. ↩

Structs

Interned

An item interned by an Interner.

Interner

An interner based on a HashSet. See the crate-level docs for more.