Guru: Using Mixed Lists To Add “Data Structures” To CL Commands

January 15, 2024 Ted Holt

I can’t remember the last time I worked on an RPG program that had no data structures, but it was probably on a System/34. Everybody uses data structures, and with good reason – they are as handy as a pocket. When writing CL commands, it is possible to include parameters that are formatted as data structures. IBM calls them mixed lists. In the following paragraphs, I show how this is accomplished.

You may not realize it, but you have used IBM-supplied commands that have mixed-list parameters. For example, the Copy File (CPYF) command has several such parameters: FROMKEY, TOKEY, INCCHAR, …