100 passes? That IBM 1401 compiler must have been a salami slicer. I was operating on the ICL 1900 range, not a machine that made it over the pond. We had to split the source across 4 files - which fooled a remarkably unthinking civil servant into thinking that we were deliberately wasting computer time by compiling the same file four times. At the end, our team of four had a daily routine of getting our source 'ok', and then going off to a restaurant dinner while the whole thing compiled itself, created the binary and ran the test suite. We'd come back after dinner and look at the results, if not actually cure the remaining problems. G