Struct RowExpressionContext 

pub struct RowExpressionContext { /* private fields */ }

Context of the expression line

A context implementation specifically designed for evaluating expressions on row data Two access modes are supported: Access by column name: via the col_name_index mapping 2. Access by variable name: via the variables mapping

Implementations

impl RowExpressionContext

pub fn new(row: Vec<Value>, col_names: Vec<String>) -> Self

Create a new line context.

pub fn from_dataset(row: &[Value], col_names: &[String]) -> Self

Create a context based on the existing data.

pub fn get_value_by_name(&self, name: &str) -> Option<&Value>

Retrieve values based on column names.

Trait Implementations

impl Clone for RowExpressionContext

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for RowExpressionContext

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

Formats the value using the given formatter.

impl ExpressionContext for RowExpressionContext

fn get_variable(&self, name: &str) -> Option<Value>

Obtain the value of the variable

fn set_variable(&mut self, name: String, value: Value)

Setting variable values

fn get_function(&self, name: &str) -> Option<OwnedFunctionRef>

Obtain a function reference

fn get_parameter(&self, _name: &str) -> Option<Value>

Obtain the value of a query parameter (@name). Default implementation returns None — contexts without parameter support simply ignore parameter references.

fn get_session_variable(&self, name: &str) -> Result<Value, ExpressionError>

Obtain the value of a session variable ($name).

fn get_variable_by_slot(&self, _slot: SlotId) -> Option<Value>

Obtain the value of a variable by slot ID (fast path). Default implementation falls back to name-based lookup.

fn get_graph_storage(&self) -> Option<GraphStorageRef>

Obtain the graph storage accessor for graph algorithm functions

fn get_sequence_manager(&self) -> Option<Arc<SequenceManager>>

Obtain the sequence catalog manager for curr_val / next_val. Default implementation returns None — contexts without sequence support report the functions’ missing-context error.

fn supports_cache(&self) -> bool

Check whether the context supports caching.

fn get_cache(&mut self) -> Option<&mut ()>

Obtain the cache manager (if available).

fn execute_subquery( &mut self, body: &SubqueryBody, ) -> Result<Vec<Value>, ExpressionError>

Execute a subquery body and return the result values.

fn execute_exists( &mut self, body: &SubqueryBody, ) -> Result<bool, ExpressionError>

EXISTS semantics: whether the subquery produces at least one row.

fn contains_subquery( &mut self, body: &SubqueryBody, value: &Value, ) -> Result<Value, ExpressionError>

IN semantics: whether value occurs in the subquery result.

fn execute_scalar_subquery( &mut self, body: &SubqueryBody, ) -> Result<Value, ExpressionError>

Scalar-subquery semantics: the first result value, or NULL when the subquery returns no rows. Streaming contexts override this to dispatch through the hosting operator’s subquery executor.

fn evaluate_label(&self, label: &str) -> Result<Value, ExpressionError>

Evaluate a :Label expression against the current row binding.

fn evaluate_list_comprehension( &mut self, variable: &str, source: &Expression, filter: Option<&Expression>, map: Option<&Expression>, ) -> Result<Value, ExpressionError>

where Self: Sized,

Evaluate a list comprehension [variable IN source WHERE filter | map].

fn evaluate_label_tag_property( &mut self, tag: &Expression, property: &str, ) -> Result<Value, ExpressionError>

where Self: Sized,

Evaluate a dynamic tag-property access tag.property where tag is itself an expression.

fn evaluate_predicate( &mut self, func: &str, args: &[Expression], ) -> Result<Value, ExpressionError>

where Self: Sized,

Evaluate a predicate expression func(variable IN list WHERE predicate) with func in {ALL, ANY, SINGLE, NONE}.

fn evaluate_reduce( &mut self, accumulator: &str, initial: &Expression, variable: &str, source: &Expression, mapping: &Expression, ) -> Result<Value, ExpressionError>

where Self: Sized,

Evaluate a REDUCE expression reduce(acc = initial, variable IN source | mapping).

fn evaluate_path_build( &mut self, items: &[Expression], ) -> Result<Value, ExpressionError>

where Self: Sized,

Evaluate a path construction expression path(v1, e1, v2, e2, v3).