I found list2env ideal for what you're describing; the trickiest bit, for me, was working out what to give for the env parameter:
f=function(){
list(a=1,b="my string")
}
ret=f()
list2env(ret,env=environment())
#a=ret$a;b=ret$b #Same as previous line
print(a);print(b) #1 and "my string"