Sherlock Holmes: the mystery of the vanishing variable
Roger Willink · ACM SIGAPL APL Quote Quad · 1987
Solving errors in other APL systems is frequently a tedious and ultimately an expensive chore. Fortunately APL is able to fully describe its own environment without the need for 'special language query tools'. This paper describes utilities which extract directive knowledge surrounding a program error. Used as a systematic discipline, they can greatly facilitate debugging and prevent potential errors in any system.