Sometime in the late 80s I was working on a new CICS system for DOS/VSE, written in PLI. I was barely trained in CICS but still the "expert" as far as my team went. I was also the PLI guy, the other programmers were COBOL folks. I wrote a system in Rexx to run under VM and generate skeleton code for transactions from text descriptions. That got enabled even beginners to create and test dummy transactions with the perspective users, iterating to get the UI to the point where they liked it, learning PLI as they worked with the generated code. Of course looking at code was how we learned a language back then anyway. We had reference manuals but not books intended to teach the language. My favorite Rexx feature: uninitialized variables had the value of their name, so there was no such thing as an NRE!