during the mid 80s, i was preparing one of the first invited talks for USENIX on the subject of regular expressions.
i had concocted a massive RE that matched all the known spellings of saddam hussein. (it was complicated,

I wonder if that was the inspiration for the Qaddafi torture test; see http://sources.vsta.org/comp.sources.unix/volume9/fastgrep/part01 (June 87)

The first time I saw "p[-1]" was looking at some regexp source. It blew/expanded my mind.