simple-symbol

There are already a lot of string interning libraries out there, so this one is mostly just for my personal use case: writing a compiler without passing around a struct everywhere.

Usage

extern crate simple_symbol;

use simple_symbol::store;

fn main() {
  
  let symbol_a = store("String");
  let symbol_b = store("String"); 
  
  assert_eq!(symbol_a, symbol_b);

  let symbol_c = store("string");

  assert_ne!(symbol_a, symbol_c);

  // Prints "String"
  println!("{}", symbol_a);

  let original: String = symbol_a.into();

  assert_eq!(original, "String".to_string());
}

Symbols are compared via usize indices, and automatically query the global SYMBOL_TABLE struct when printing or converting.

Limitations

• Single thread only (uses thread_local! macro)
• Allocates every String twice (once as a HashMap key, once as a Vec entry)
• Currently no garbage-collecting mechanism for unused cached Strings.

Changelog

1.0.0

Derive PartialOrd and Ord for Symbol for easier use as keys in crates like petgraph.

0.1.0

Initial implementation.