Also, I have no doubt that GLS is influenced by APL - he mentions in an interview (it was either in _Coders at Work_ or on SE Radio (http://www.se-radio.net/2006/11/episode-36-interview-guy-ste...); I recommend both) that APL was one of the first programming languages he learned.
If you're interested in this thread I highly recommend Backus's "Can Programming be Liberated from the Von Nueman Style". It covers both the evils of accumulators, as well as creating languages with provable algebraic properties. Certainly I don't think anyone today would really enjoy programming in FP or FL, but I do think his thoughts are ripe for modernizing.
