Assignment As Well As Extraction

[GregYannes]

The Arr_Index() function is inspired by pluck() in the R language. Now pluck() may be used to assign as well as to extract:

# Extract.
pluck(.x, ...)


# Assign.
pluck(.x, ...) <- value

We might analogously implement Arr_Index() as a property the user may both assign and extract:

' Extract.
Arr_Index(arr, Array(…))


' Assign.
Let Arr_Index(arr, Array(…)) = 0

Set Arr_Index(arr, Array(…)) = Nothing