Struct Stack 

pub struct Stack { /* private fields */ }

Context for storing and managing variables during query execution with scope support

Implementations

impl Stack

pub fn new() -> Self

Create a new variable context with a global scope

pub fn enter_scope(&mut self, scope_type: ScopeType)

Enter a new scope (push onto stack)

pub fn exit_scope(&mut self) -> Result<()>

Exit the current scope (pop from stack) Returns error if trying to exit the global scope

pub fn scope_depth(&self) -> usize

Get the current scope depth (0 = global scope)

pub fn current_scope_type(&self) -> &ScopeType

Get the type of the current scope

pub fn set( &mut self, name: String, variable: Variable, mutable: bool, ) -> Result<()>

Set a variable in the current (innermost) scope (allows shadowing)

pub fn reassign(&mut self, name: String, variable: Variable) -> Result<()>

Reassign an existing variable (checks mutability)

pub fn set_in_current_scope( &mut self, name: String, variable: Variable, mutable: bool, ) -> Result<()>

Set a variable specifically in the current scope Allows shadowing - new variable declarations can shadow existing ones

pub fn get(&self, name: &str) -> Option<&Variable>

Get a variable by searching from innermost to outermost scope

pub fn get_with_scope(&self, name: &str) -> Option<(&Variable, usize)>

Get a variable with its scope depth information

pub fn exists_in_current_scope(&self, name: &str) -> bool

Check if a variable exists in the current scope only

pub fn exists_in_any_scope(&self, name: &str) -> bool

Check if a variable exists in any scope (searches all scopes)

pub fn is_mutable(&self, name: &str) -> bool

Check if a variable is mutable (searches from innermost scope)

pub fn all_variable_names(&self) -> Vec<String>

Get all variable names from all scopes (for debugging)

pub fn visible_variable_names(&self) -> Vec<String>

Get variable names visible in current scope (respects shadowing)

pub fn clear(&mut self)

Clear all variables in all scopes (reset to just global scope)

Trait Implementations

impl Clone for Stack

fn clone(&self) -> Stack

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Stack

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

Formats the value using the given formatter.

impl Default for Stack

fn default() -> Self

Returns the “default value” for a type.