Struct SymbolTable 

pub struct SymbolTable { /* private fields */ }

Used to resolve and lookup symbols.

Implementations

impl SymbolTable

pub fn new() -> Self

Creates a new and empty symbol table.

Example

let table = SymbolTable::new();

assert_eq!(table.len(), 0);

pub fn resolve(&self, string: impl AsRef<str>) -> Option<Symbol>

Tries to resolve the given string into an existing Symbol.

If no symbol with the given name is known, None is returned. If a new symbol should be created instead, use find_or_create.

Example

let mut table = SymbolTable::new();

let symbol = table.find_or_create("Test").unwrap();

assert_eq!(table.resolve("Test").unwrap(), symbol);
assert_eq!(table.resolve("Unknown").is_none(), true);

pub fn find_or_create(&mut self, string: impl AsRef<str>) -> Result<Symbol>

Resolve the given string into a new or an existing Symbol.

If no symbol should be created if the given name is unknown, use resolve.

Errors

This will return an error if the internal symbol table overflows (if there are more than std::i32::MAX - 2 symbols).

Example

let mut table = SymbolTable::new();

let symbol = table.find_or_create("Test").unwrap();
assert_eq!(table.resolve("Test").unwrap(), symbol);

pub fn lookup(&self, symbol: Symbol) -> &str

Retrieves the name of the given Symbol.

Examples

let mut table = SymbolTable::new();

let symbol = table.find_or_create("Test").unwrap();

// A known symbol can be looked up...
assert_eq!(table.lookup(symbol), "Test");

// An unknown symbol is simply translated to ""
assert_eq!(table.lookup(1024), "");

pub fn len(&self) -> usize

Determines the number of known symbols in the table.

Examples

let mut table = SymbolTable::new();

// The same symbol is only added once to a table...
let symbol = table.find_or_create("Test").unwrap();
let symbol1 = table.find_or_create("Test").unwrap();
assert_eq!(symbol, symbol1);

// ..therefore the table size is 1.
assert_eq!(table.len(), 1);

// If we add another symbol...
table.find_or_create("Test 2").unwrap();

// ...the size grows to 2.
assert_eq!(table.len(), 2);

pub fn allocated_size(&self) -> usize

Estimates the allocated memory required to represent the symbol table.

Note that this is only an approximation as some inner types to not reveal their size.

Example

let mut table = SymbolTable::new();

table.find_or_create("Hello").unwrap();
table.find_or_create("World").unwrap();

println!("{}", table.allocated_size());