It's not quite the same. The first-match in regular expressions means that in a pattern `a|b` if `a` matches then it's preferred over `b` even if it would make a longer match. 
Problem is the statement above is valid when applied to `one particular position in the input`.

More importantly and I feel sorry for missing that form the get go, is current behaviour goes against much more efficient implementation of the proposed construct. I have a plan (that is not terribly hard) to implement it exactly as I outlined.