David A. Black wrote:
Without researching it at all, I'd guess that it traces back to an April Fool's Joke in comp.lang.perl that was subsequently described in Chapter 7 of the Camel Book as "Perl Poetry" (http://www.unix.org.ua/orelly/perl/prog3/ch27_02.htm\). Larry feigned innocence, but I never bought it.
I remember that example, though it still doesn't explain the equation
of the idea of "poetry mode" with lack of parentheses.
I don't think "poetry mode" means "parentheses prohibited". It means "parentheses optional", as distinct from "parentheses required". And indeed, the example poems sport numerous parentheses, all serving essential literary purposes :-).
Oh well -- my curiosity stops short of being willing to trace ten
years of evolution of usage, so I guess it will remain a mystery
Same here. But there's a Ph.D. just waiting for some budding pomo cyber-linguist.
Steve