Struct SymTab 

pub struct SymTab { /* private fields */ }

A simple symbol table that maps string names to integer values.

Each inserted name receives a stable index corresponding to its insertion order. Re-inserting the same name returns the existing index.

Implementations

impl SymTab

pub fn new() -> Self

Creates a new, empty symbol table.

pub fn len(&self) -> usize

Returns the number of entries currently stored in the symbol table.

Each entry corresponds to a unique symbol (e.g., variable or identifier) that has been interned.

Example

let mut symtab = SymTab::new();
assert_eq!(symtab.len(), 0);
symtab.intern("foo");
assert_eq!(symtab.len(), 1);
symtab.intern("baz");
assert_eq!(symtab.len(), 2);
symtab.intern("foo");
assert_eq!(symtab.len(), 2);

pub fn intern(&mut self, name: impl AsRef<str>) -> usize

Inserts the given name if it doesn’t exist and returns its index.

If the name already exists, this returns the existing index without modifying the stored value.

Examples

let mut st = SymTab::new();
let i = st.intern("a");
assert_eq!(i, 0);
assert_eq!(st.intern("a"), 0); // existing index

pub fn set(&mut self, index: usize, new_value: i64) -> Result<(), SymTabError>

Updates the value at the given index.

Returns Err if the index is out of bounds.

Examples

let mut st = SymTab::new();
let i = st.intern("x");
st.set(i, 123).unwrap();
assert_eq!(st.get(i).unwrap(), 123);

pub fn get(&self, index: usize) -> Result<i64, SymTabError>

Returns the value stored at the given index.

Returns Err if the index is out of bounds.

Trait Implementations

impl Debug for SymTab

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

Formats the value using the given formatter.