Enum egglang::scope::Scope

pub enum Scope {
    Global {
        source: BTreeMap<ArcStr, Value>,
        extras: ScopeExtras,
    },
    Local {
        overlay: BTreeMap<ArcStr, Value>,
        source: *mut Scope,
    },
}

A Scope is responsible for keeping track of script state.

This includes storing variables, which are plain Values. Function and Objects values are simple indexes|references to FunctionDefinitions and BTreeMaps, stored in ScopeExtras.

ScopeExtras is only attached to the Global Scope, meaning Functions and Objects are always global, even if defined in a script function.

The default scope comes with several constants built-in:

{
     "Boolean": "__TYPE__BOOLEAN",
     "Function": "__TYPE__FUNCTION",
     "Nil": "__CONSTANT__NIL",
     "Number": "__TYPE__NUMBER",
     "Object": "__TYPE__OBJECT",
     "String": "__TYPE__STRING",
     "PI": 3.1415927,
     "E": 2.7182817,
     "TAU": 6.2831855,
     "false": false,
     "true": true
 }

Variants

Global

Fields

source: BTreeMap<ArcStr, Value>

extras: ScopeExtras

Local

Fields

overlay: BTreeMap<ArcStr, Value>

source: *mut Scope

Implementations

impl Scope

pub fn get_function_definition( &self, idx: usize ) -> EggResult<&FunctionDefinition>

pub fn get_function_definition_mut( &mut self, idx: usize ) -> EggResult<&mut FunctionDefinition>

pub fn call_function( &mut self, idx: usize, parameters: &[Expression], operators: &BTreeMap<&str, Box<dyn Operator>> ) -> EggResult<Value>

pub fn delete_function(&mut self, idx: usize) -> Option<FunctionDefinition>

impl Scope

pub fn create_object(&mut self) -> EggResult<Value>

pub fn get_object_tag(&self, tag: Value) -> EggResult<usize>

pub fn get_object(&self, tag: usize) -> &BTreeMap<Value, Value>

pub fn get_object_mut(&mut self, tag: usize) -> &mut BTreeMap<Value, Value>

pub fn delete_object(&mut self, tag: usize) -> Option<BTreeMap<Value, Value>>

impl Scope

pub fn exists(&self, key: &str) -> bool

Check if a variable exists anywhere in the scope chain.

pub fn exists_locally(&self, key: &str) -> bool

Check if a variable exists in the current scope. Has similar behaviour to exists for the Global Scope. Used to check if a variable is defined in the current scope, and not in the parent scope.

pub fn get(&self, key: &str) -> Option<&Value>

Fetch for a variable in the current scope and its parent scopes.

pub fn get_mut(&mut self, key: &str) -> Option<&mut Value>

Mutable fetch for a variable in the current scope and its parent scopes.

pub fn insert(&mut self, key: ArcStr, value: Value) -> EggResult<()>

Insert a new variable into the current scope.

pub fn update(&mut self, key: ArcStr, value: Value)

Updates the value of a variable if it is in the present scope, otherwise updates it in the parent scope.

pub fn delete(&mut self, key: &str) -> Option<Value>

Delete a variable if it is the present scope, otherwise delete it from the parent scope.

Trait Implementations

impl Debug for Scope

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

Formats the value using the given formatter.

impl Default for Scope

fn default() -> Scope

Returns the “default value” for a type.