Struct ExprArena 

pub struct ExprArena { /* private fields */ }

Flat, index-addressed storage for all IrExpr nodes in a query plan.

Nodes are appended with push, which returns a stable ExprId index. Because the arena is a plain Vec, serialisation produces a JSON array where each element’s position is its ExprId.

Example

use graphforge_ir::{ExprArena, IrExpr, IrLiteral, VarId, PropId};
use graphforge_ir::expr::BinaryOpKind;

let mut arena = ExprArena::new();

// Build: name = "Alice"
let var = arena.push(IrExpr::VarRef(VarId(0)));
let prop = arena.push(IrExpr::PropertyAccess { base: var, prop: PropId(1) });
let lit = arena.push(IrExpr::Literal(IrLiteral::Str("Alice".into())));
let eq  = arena.push(IrExpr::BinaryOp { op: BinaryOpKind::Eq, left: prop, right: lit });

assert_eq!(arena.get(eq), &IrExpr::BinaryOp { op: BinaryOpKind::Eq, left: prop, right: lit });

Implementations

impl ExprArena

pub fn new() -> Self

Creates an empty arena.

pub fn push(&mut self, expr: IrExpr) -> ExprId

Appends expr to the arena and returns its stable ExprId.

pub fn get(&self, id: ExprId) -> &IrExpr

Returns a reference to the expression at id.

Panics

Panics if id is out of bounds (i.e. was not returned by this arena’s push).

pub fn substitute_parameters(&mut self, params: &HashMap<String, IrLiteral>)

Replace named parameter nodes with supplied literal values.

pub fn len(&self) -> usize

Returns the number of expressions in the arena.

pub fn is_empty(&self) -> bool

Returns true if the arena contains no expressions.

Trait Implementations

impl Clone for ExprArena

fn clone(&self) -> ExprArena

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for ExprArena

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

Formats the value using the given formatter.

impl Default for ExprArena

fn default() -> ExprArena

Returns the “default value” for a type.

impl<'de> Deserialize<'de> for ExprArena

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl PartialEq for ExprArena

fn eq(&self, other: &ExprArena) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl Serialize for ExprArena

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl StructuralPartialEq for ExprArena