Dyalog APL

Dyalog APL, or simply Dyalog, is a modern APL in the APL2 tradition, first released by British company Dyadic Systems Ltd. (now Dyalog Ltd.) in 1983 for the Zylog Z80 processor (the name Dyalog is a portmanteau of Dyadic and Zylog). Dyalog supports several platforms and interfaces with many languages and runtimes including native shared libraries, .NET, the JVM, R, and Python. It is actively developed and has introduced many new primitives and concepts to array programming. Major categories of features introduced to APL by Dyalog are tacit programming by allowing named derived functions and later trains, lexically-scoped functional programming using dfns, namespaces and object-oriented programming, and the addition of leading axis theory and the Rank operator to the nested array paradigm.

In 1995, two Dyalog developers—John Scholes and Peter Donnelly—were awarded the Iverson Award for their work on the interpreter. Gitte Christensen and Morten Kromberg were joint recipients of the Iverson Award in 2016.

Versions
Dyalog lists historical versions, along with release notes since 14.0, on its website. Its early history is recounted in more detail by Pete Donnelly in Dyalog APL: A Personal History (pdf).