Roger Kwok Wah Hui (born 1953) is a computer scientist and co-developer of the programming language J, and later Dyalog APL.
Hui's work was described at the APL85 conference in a paper, "DESIGN: A Financial Modelling System", written jointly with his supervisor, Fred Appleyard. The basic objects in the system were in "Direct Definition" (Iverson, 1976, 1980), and Falkoff and Iverson's The Design of APL was cited. Hui left Alberta Energy shortly after being promoted to a non-APL and non-programming position, and was out of work, and had no access to computers, from September 1985 to April 1986. This gave him plenty of time for intense study of Iverson's Rationalized APL (1983) and A Dictionary of the APL Language, as it was then named.
Roger Hui runs and maintains the Jsoftware website.