Register a reduction operation.

Stores a user-defined reduction function under the given name so that it can be retrieved by get_reduction() and invoked during query evaluation.

Usage

register_reduction(name, fn, overwrite = FALSE)

Arguments

name

Op name (character scalar, matches token in query strings).

fn

Function function(x, ...) where x is a numeric vector or matrix column and ... collects named parameters.

overwrite

Logical scalar; set to TRUE to replace an already- registered operation.

Value

Invisibly NULL.

Examples

register_reduction("Median_example", function(x, ...) median(x, ...), overwrite = TRUE)
registered_reductions()
#>  [1] "Count"          "GeoMean"        "Max"            "Mean"          
#>  [5] "Median"         "Median_example" "Min"            "Mode"          
#>  [9] "Quantile"       "Std"            "StdN"           "Sum"           
#> [13] "Var"            "VarN"