To compile changes you reran the translation system. You could write segments of C, but you had to track down what the variable names had been translated to. The codebase was a mishmash of old cobol and sections of C code bracketed by "start verbatim" and "end verbatim". We dubbed it C-bol

Oh, and this was in 1998. Yes, reader, our C code had a Y2K problem. A good chunk of my time there was spent working on eliminating all the 2 digit years in the codebase. I left in early 1999 for a Java programming role somewhere who (truthfully) promised me that they weren't taking on Y2K work.