Struct netsblox_vm::runtime::SymbolTable

pub struct SymbolTable<'gc, C: CustomTypes<S>, S: System<C>>(_);

Holds a collection of variables in an execution context.

SymbolTable has utilities to extract variables from an abstract syntax tree, or to explicitly define variables. Simple methods are provided to perform value lookups in the table.

Implementations

impl<'gc, C: CustomTypes<S>, S: System<C>> SymbolTable<'gc, C, S>

pub fn define_or_redefine( &mut self, var: &str, value: Shared<'gc, Value<'gc, C, S>> )

Defines or redefines a value in the symbol table to a new instance of Shared<Value>. If a variable named var already existed and was Shared::Aliased, its value is not modified.

pub fn define_if_undefined<F: FnOnce() -> Shared<'gc, Value<'gc, C, S>>>( &mut self, var: &str, f: F )

Defines a variable with an initial value if it does not already exist in this symbol table. If a variable with the given name already exists, this is a no-op.

pub fn lookup(&self, var: &str) -> Option<&Shared<'gc, Value<'gc, C, S>>>

Looks up the given variable in the symbol table. If a variable with the given name does not exist, returns None.

pub fn lookup_mut( &mut self, var: &str ) -> Option<&mut Shared<'gc, Value<'gc, C, S>>>

Equivalent to SymbolTable::lookup except that it returns a mutable reference.

pub fn len(&self) -> usize

Gets the number of symbols currently stored in the symbol table.

pub fn is_empty(&self) -> bool

Checks if the symbol table is currently empty (no defined symbols).

pub fn iter(&self) -> Iter<'gc, '_, C, S>

Iterates over the key value pairs stored in the symbol table.

pub fn iter_mut(&mut self) -> IterMut<'gc, '_, C, S>

Iterates over the key value pairs stored in the symbol table.

Trait Implementations

impl<'gc, C: CustomTypes<S>, S: System<C>> Clone for SymbolTable<'gc, C, S>

fn clone(&self) -> Self

Creates a shallow (non-aliasing) copy of all variables currently stored in this symbol table.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<'gc, C: CustomTypes<S>, S: System<C>> Collect for SymbolTable<'gc, C, S>

fn needs_trace() -> bool

As an optimization, if this type can never hold a Gc pointer and trace is unnecessary to call, you may implement this method and return false. The default implementation returns true, signaling that Collect::trace must be called.

fn trace(&self, cc: &Collection)

Must call Collect::trace on all held Gc pointers. If this type holds inner types that implement Collect, a valid implementation would simply call Collect::trace on all the held values to ensure this.

impl<'gc, C: CustomTypes<S>, S: System<C>> Default for SymbolTable<'gc, C, S>

fn default() -> Self

Returns the “default value” for a type.

impl<'gc, 'a, C: CustomTypes<S>, S: System<C>> IntoIterator for &'a SymbolTable<'gc, C, S>

type Item = <Iter<'gc, 'a, C, S> as Iterator>::Item

The type of the elements being iterated over.

type IntoIter = Iter<'gc, 'a, C, S>

Which kind of iterator are we turning this into?

fn into_iter(self) -> Self::IntoIter

Creates an iterator from a value.

impl<'gc, 'a, C: CustomTypes<S>, S: System<C>> IntoIterator for &'a mut SymbolTable<'gc, C, S>

type Item = <IterMut<'gc, 'a, C, S> as Iterator>::Item

The type of the elements being iterated over.

type IntoIter = IterMut<'gc, 'a, C, S>

Which kind of iterator are we turning this into?

fn into_iter(self) -> Self::IntoIter

Creates an iterator from a value.

impl<'gc, C: CustomTypes<S>, S: System<C>> IntoIterator for SymbolTable<'gc, C, S>

type Item = (String, Shared<'gc, Value<'gc, C, S>>)

The type of the elements being iterated over.

type IntoIter = IntoIter<'gc, C, S>

Which kind of iterator are we turning this into?

fn into_iter(self) -> Self::IntoIter

Creates an iterator from a value.