Trait datafusion_expr::registry::FunctionRegistry

pub trait FunctionRegistry {
    // Required methods
    fn udfs(&self) -> HashSet<String>;
    fn udf(&self, name: &str) -> Result<Arc<ScalarUDF>>;
    fn udaf(&self, name: &str) -> Result<Arc<AggregateUDF>>;
    fn udwf(&self, name: &str) -> Result<Arc<WindowUDF>>;
    fn expr_planners(&self) -> Vec<Arc<dyn ExprPlanner>>;

    // Provided methods
    fn register_udf(
        &mut self,
        _udf: Arc<ScalarUDF>,
    ) -> Result<Option<Arc<ScalarUDF>>> { ... }
    fn register_udaf(
        &mut self,
        _udaf: Arc<AggregateUDF>,
    ) -> Result<Option<Arc<AggregateUDF>>> { ... }
    fn register_udwf(
        &mut self,
        _udaf: Arc<WindowUDF>,
    ) -> Result<Option<Arc<WindowUDF>>> { ... }
    fn deregister_udf(&mut self, _name: &str) -> Result<Option<Arc<ScalarUDF>>> { ... }
    fn deregister_udaf(
        &mut self,
        _name: &str,
    ) -> Result<Option<Arc<AggregateUDF>>> { ... }
    fn deregister_udwf(&mut self, _name: &str) -> Result<Option<Arc<WindowUDF>>> { ... }
    fn register_function_rewrite(
        &mut self,
        _rewrite: Arc<dyn FunctionRewrite + Send + Sync>,
    ) -> Result<()> { ... }
    fn register_expr_planner(
        &mut self,
        _expr_planner: Arc<dyn ExprPlanner>,
    ) -> Result<()> { ... }
}

A registry knows how to build logical expressions out of user-defined function’ names

Required Methods

fn udfs(&self) -> HashSet<String>

Set of all available udfs.

fn udf(&self, name: &str) -> Result<Arc<ScalarUDF>>

Returns a reference to the user defined scalar function (udf) named name.

fn udaf(&self, name: &str) -> Result<Arc<AggregateUDF>>

Returns a reference to the user defined aggregate function (udaf) named name.

fn udwf(&self, name: &str) -> Result<Arc<WindowUDF>>

Returns a reference to the user defined window function (udwf) named name.

fn expr_planners(&self) -> Vec<Arc<dyn ExprPlanner>>

Set of all registered ExprPlanners

Provided Methods

fn register_udf( &mut self, _udf: Arc<ScalarUDF>, ) -> Result<Option<Arc<ScalarUDF>>>

Registers a new ScalarUDF, returning any previously registered implementation.

Returns an error (the default) if the function can not be registered, for example if the registry is read only.

fn register_udaf( &mut self, _udaf: Arc<AggregateUDF>, ) -> Result<Option<Arc<AggregateUDF>>>

Registers a new AggregateUDF, returning any previously registered implementation.

Returns an error (the default) if the function can not be registered, for example if the registry is read only.

fn register_udwf( &mut self, _udaf: Arc<WindowUDF>, ) -> Result<Option<Arc<WindowUDF>>>

Registers a new WindowUDF, returning any previously registered implementation.

Returns an error (the default) if the function can not be registered, for example if the registry is read only.

fn deregister_udf(&mut self, _name: &str) -> Result<Option<Arc<ScalarUDF>>>

Deregisters a ScalarUDF, returning the implementation that was deregistered.

Returns an error (the default) if the function can not be deregistered, for example if the registry is read only.

fn deregister_udaf(&mut self, _name: &str) -> Result<Option<Arc<AggregateUDF>>>

Deregisters a AggregateUDF, returning the implementation that was deregistered.

Returns an error (the default) if the function can not be deregistered, for example if the registry is read only.

fn deregister_udwf(&mut self, _name: &str) -> Result<Option<Arc<WindowUDF>>>

Deregisters a WindowUDF, returning the implementation that was deregistered.

Returns an error (the default) if the function can not be deregistered, for example if the registry is read only.

fn register_function_rewrite( &mut self, _rewrite: Arc<dyn FunctionRewrite + Send + Sync>, ) -> Result<()>

Registers a new FunctionRewrite with the registry.

FunctionRewrite rules are used to rewrite certain / operators in the logical plan to function calls. For example a || b might be written to array_concat(a, b).

This allows the behavior of operators to be customized by the user.

fn register_expr_planner( &mut self, _expr_planner: Arc<dyn ExprPlanner>, ) -> Result<()>

Registers a new ExprPlanner with the registry.

Implementors

impl FunctionRegistry for MemoryFunctionRegistry