OM# Documentation

`CLASS-ARRAY`

CLASS-ARRAY provides powerful means to set the contents of a 2D array. The array is initialized by a number of columns (called “fields”) and a number of rows (called “elements”, sometimes abreviated “elts”).

→ See also 2D-ARRAY for a simple 2D data storage and representation utility.

The main parameters of the CLASS-ARRAY object are:

:field-names: a list of names (stings), whose length will also determine the number of fileds, or rows in the array.
:num-elts: an integer number determining th enumber of rows.

Given these two initialization parameters, each field can then be initialized individually using the box keyword-inputs (see below).

Array field initialization

In order to set a CLASS-ARRAY field, add a keywork input to the class and select the corresponding field name.

Note: If the box was never evaluated before, the fields in :field-names might not be readily available from the keyword input choice. In this case (and in any case) it is also possible to create a field with the last option in the input menu, :add field.

Each field will be filled at evaluating the CLASS-ARRAY box with the number of elements specified in :num-elts, according to a set of rules depending in the type of input data:

A list provides a value for each element, and is repeated cyclically if shorter than num-elts, untill all elements have a value.

A simple value is repeated num-elts times in order to fill all the elements.

A BPF is sampled with num-elts values.

A lambda patch or function is evaluated num-elts times with one argument (the element index: 0, 1, ..., num-elts)

Copy and transformation

When copying a CLASS-ARRAY to another box, it is possible to reset some of the box inputs and transform the array contents accordingly:

Setting a new value for :num-elts will resize the array fields with another number of elements, cutting or cycling through the list as necessary.
Setting a new list of :fileld-names will create a new set of fields and copy the existing ones (based on the field names) from the original array.
Setting one of the fields individually using the corresponding keyword-inputs will change the values in this specific field.

Data access

get-array-data retrieves the full evaluated contents of the CLASS-ARRAY as a raw list of lists, suitable for processing through conventional Lisp structures and utilities.
get-field returns the evaluated form of one specific field (from either a field name or index).
get-comp returns an orthogonal view of the values of one columns/element in the array. Components are returned as instances of the COMPONENT structures, and can be accessed as raw values using the functions comp-list (all values) or comp-field (one specific field).

In-pace modification

The functions in the package “Basic Tools / Class-Array and Components” include utilities for in-place, destructive modification of a CLASS-ARRAY. They all use the COMPONENT structure representing one column, or element of the array, as returned by get-comp, or created by new-comp. add-comp and remove-comp add or remove these components, while comp-list and comp-field both have an optional input allowing to replace the component values by new ones, inside the original array.