ZF Expressions (aka list comprehensions) date to at least David Turner's KRC (St. Andrews Static Language) and Rod Burstall and John Darlington's Hope c.1980. Maybe they were present in NPL, the predecessor of Hope before that. The Hope paper nods to SETL as an influence. Without interviewing the people concerned its probably impossible to actually find out what influenced what - even though list comprehensions have a long history the designers of Python might have only seen them in Haskell so Python could well have "got" them from Haskell. Hope - An Experimental Applicative language http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.18.8135 The language guide is truly strange - maybe it was written by work experience students. The Icon entry made me smile, although the SML entry where they missed a crucial suffix is good too - "The current implementation is Moscow" - what, the city implements a programming a language?