Re:Sat solver on top of regex matcher
by Thorrez on Thursday June 25, 2020 @12:47AM
(#23637012)
> Regex won't work on its own, you generally need more semantic information
Yeah, I agree. My point was that regex won't work, regardless of if you have backreferences or not. So backreferences won't help.
> But more broadly, any situation where you search from a non-zero index has this problem.
I'm not sure I understand that. A lot of regex libraries let you specify a start index. It won't take into account data from before the start index though (regex doesn't really do that, regardless of backreferences). If your regex library doesn't support passing in a start index, you can just take a substring starting at that index, then search the substring.
I don't think Python is really special. Python's findall() is just a convenience function that does a loop finding a match, then finding another match that starts after the first match, etc. Most languages provide a way to find the end point of the most recent match, and then you can just write the loop yourself to start the next search at that point.
Yeah, I agree. My point was that regex won't work, regardless of if you have backreferences or not. So backreferences won't help.
> But more broadly, any situation where you search from a non-zero index has this problem.
I'm not sure I understand that. A lot of regex libraries let you specify a start index. It won't take into account data from before the start index though (regex doesn't really do that, regardless of backreferences). If your regex library doesn't support passing in a start index, you can just take a substring starting at that index, then search the substring.
I don't think Python is really special. Python's findall() is just a convenience function that does a loop finding a match, then finding another match that starts after the first match, etc. Most languages provide a way to find the end point of the most recent match, and then you can just write the loop yourself to start the next search at that point.