Struct DefaultExpressionContext 

pub struct DefaultExpressionContext { /* private fields */ }

The evaluation context of the default expression

Provide the contextual environment required for evaluating the expression, including: Variable storage Function registration (using a global function registry) Optional graph storage accessor for graph algorithm functions

Note: This context is used for the evaluation of runtime expressions. For compilation-time analysis, please use ExpressionAnalysisContext.

Implementations

impl DefaultExpressionContext

pub fn new() -> Self

Create a new context without graph storage access.

pub fn with_storage( storage: Arc<RwLock<dyn StorageReader>>, space: String, ) -> Self

Create a new context with graph storage access.

pub fn with_parameters(self, parameters: Arc<HashMap<String, Value>>) -> Self

Attach a parameter name → value map so Expression::Parameter references resolve at evaluation time.

pub fn with_session_variables( self, variables: Arc<HashMap<String, Value>>, ) -> Self

Attach a session variable snapshot so Expression::SessionVariable references resolve at evaluation time.

pub fn add_variable(self, name: String, value: Value) -> Self

Add a variable

pub fn with_variables<I>(self, variables: I) -> Self

where I: IntoIterator<Item = (String, Value)>,

Add variables in batches

pub fn from_execution_context(ctx: &ExecutionContext) -> Self

Create a DefaultExpressionContext from the ExecutionContext.

Copy all variables from the ExecutionContext to the new DefaultExpressionContext.

pub fn sync_to_execution_context(self, ctx: &ExecutionContext)

Synchronize the variable back to the ExecutionContext.

Synchronize all variables from the current DefaultExpressionContext to the ExecutionContext.

pub fn get_all_variables(&self) -> &HashMap<String, Value>

Get all variables for debugging

Trait Implementations

impl Debug for DefaultExpressionContext

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

Formats the value using the given formatter.

impl Default for DefaultExpressionContext

fn default() -> Self

Returns the “default value” for a type.

impl ExpressionContext for DefaultExpressionContext

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_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_function(&self, name: &str) -> Option<OwnedFunctionRef>

Obtain a function reference

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 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 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).