what's good, non-recursive algorithm calculate cartesian product?

note

this rebol-specific question. answer any language.

background

the libel supports origination domain-specific languages famous "dialects" rebol parlance. i've combined such section list comprehensions, aren't natively upheld rebol.

a good cartesian product algorithm indispensable list comprehensions.

the problem

i've used meta-programming solve this, boldly formulating following executing method nested foreach statements. works beautifully. however, since it's dynamic, formula unequivocally readable. rebol doesn't recursion well. fast runs out smoke-stack space crashes. recursive fortitude out question.

in sum, i wish reinstate meta-programming readable, non-recursive, "inline" algorithm, possible. fortitude any language, enlarged i imitate rebol. (i review only any programming language: c#, c, c++, perl, oz, haskell, erlang, whatever.)

i should highlight algorithm needs support an erratic array sets "joined", given list grasp secure any array sets.