The compact display of arbitrary nested arrays

An enhanced array display function, upward compatible from the one supplied with APL2, is presented. It overcomes several difficulties involved with the display of very large or very deep nested arrays, and permits convenient examination of arrays which would otherwise overflow the screen or observation window. Sub-array replication and sub-array similarity in the displayed array are considered at every depth, and presented in a straightforward shorthand notation if invoked. Also, leaf detail is elided by general compaction, but only if it precludes a reasonable overall display size.