andy-hanson / rust-symbol

Lifetimed symbol table for Rust

symbol

A symbol table implementation for Rust.

Unlike other libraries, it doesn't just use a global 'static symbol table. It is lifetimed -- the symbol table is deleted when you're done with it, and symbols are scoped to the table -- and it supports multiple tables, each with its own symbol type.

Using

Cargo.toml:

[package]
...

[dependencies]
symbol = { git = "https://github.com/andy-hanson/rust-symbol.git" }

src/main.rs:

extern crate core; // Used by symbol_type macro
#[macro_use(symbol_type)]
extern crate symbol;
use symbol::SymbolTable;

// Declare a symbol type for this table.
symbol_type!(TestSymbol);

fn main() {
	let mut table: SymbolTable<TestSymbol> = SymbolTable::new();
	let sym1 = table.intern(&"foofoo"[0..2]);
	let sym2 = table.intern(&"foofoo"[3..5]);
	assert_eq!(sym1, sym2);
}

Details

The source code is fairly short.

The table does not copy string data to itself, so any strings referenced must have a lifetime greater than the table.

Every symbol type derives from the Symbol trait. Symbols are Copy and should not be borrowed. They have a lifetime parameter to ensure that they don't last longer than the strings they reference.