principle of least surprise

[Richard A. O'Keefe]

"Ulf Wiger (AL/EAB)" <ulf.wiger@REDACTED> wrote:
	Now, the 'anti-monad' would truly be warm and fuzzy, and should
	be allowable in guards (and most likely also in select patterns).
	
	Erlang WFTs, in other words, would be the thing to allow in 
	guards.  (:
	
Abstract patterns are pretty much exactly the "warm fuzzy things" you
would want to allow in guards.  Amongst other things, they cannot run
forever or have any side effects.