Module datafusion_physical_expr::functions

Declaration of built-in (scalar) functions. This module contains built-in functions’ enumeration and metadata.

Generally, a function has:

• a signature

• a return type, that is a function of the incoming argument’s types

• the computation, that must accept each valid signature

• Signature: see Signature

• Return type: a function (arg_types) -> return_type. E.g. for sqrt, (f32) -> f32, (f64) -> f64.

This module also supports coercion to improve user experience: if an argument i32 is passed to a function that supports f64, the argument is automatically is coerced to f64.

Functions

• create_physical_expr
  Create a physical (function) expression. This function errors when args’ can’t be coerced to a valid argument type of the function.
• create_physical_fun
  Create a physical scalar function.
• get_func_monotonicity
  This function specifies monotonicity behaviors for built-in scalar functions. The list can be extended, only mathematical and datetime functions are considered for the initial implementation of this feature.
• make_scalar_function
  decorates a function to handle ScalarValues by converting them to arrays before calling the function and vice-versa after evaluation.
• out_ordering
  Determines a ScalarFunctionExpr’s monotonicity for the given arguments and the function’s behavior depending on its arguments.

Type Aliases

• FuncMonotonicity
  Monotonicity of the ScalarFunctionExpr with respect to its arguments. Each element of this vector corresponds to an argument and indicates whether the function’s behavior is monotonic, or non-monotonic/unknown for that argument, namely: