Struct SymbolStore 

pub struct SymbolStore { /* private fields */ }

An append-only, deduplicating registry of identifier strings.

Interning takes &self, not &mut self: elaboration and typechecking both mint new derived names mid-pass (qualify_key’s "M.x", $-mangled module keys, "%patbind…", fresh desugar names like "%cmd_arg0", qualified constructor lookup keys), so the store must stay interned-into while the tree it brands is being walked. Hence the interior mutability.

Entries are never removed or mutated, which is what makes resolve able to hand out &strs that live as long as the store borrow.

Implementations

impl SymbolStore

pub fn new() -> SymbolStore

pub fn intern<'s>(&'s self, text: &str) -> Symbol<'s>

Intern text, returning its symbol. Interning the same text twice returns the same symbol.

pub fn resolve<'s>(&'s self, sym: Symbol<'s>) -> &'s str

The text sym was interned from.

Panics

If sym was minted by a different store that happened to share this one’s borrow lifetime and holds more entries than this one. The brand makes that hard to write by accident and it is not unsound — the bounds check below turns it into a panic rather than a bogus read — but a program should still keep one store per pipeline run.

pub fn len(&self) -> usize

How many distinct strings have been interned. (Also the index the next new symbol will get — useful for sizing dense side-tables.)

pub fn is_empty(&self) -> bool

Trait Implementations

impl Debug for SymbolStore

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for SymbolStore

fn default() -> SymbolStore

Returns the “default value” for a type.