Add functions that perform conversion to a desired class.

Whenever a Graph or a PipeOp is called with an object that does not conform to its declared input type, the "autoconvert register" is queried for functions that may turn the object into a desired type.

Conversion functions should try to avoid cloning.

## Usage

register_autoconvert_function(cls, fun, packages = character(0))

## Arguments

cls

character(1) The class that fun converts to.

fun

function The conversion function. Must take one argument and return an object of class cls, or possibly a sub-class as recognized by are_types_compatible().

packages

character The packages required to be loaded for fun to operate.

## Value

NULL.

Other class hierarchy operations: add_class_hierarchy_cache(), reset_autoconvert_register(), reset_class_hierarchy_cache()
# This lets mlr3pipelines automatically try to convert a string into
# a PipeOp by querying the [mlr_pipeops] [Dictionary][mlr3misc::Dictionary].