“Assert that the regex below can be matched, starting at this position”.
Let’s go with this little example:
This would mean, match a space between one and many times followed by a word character between one and many times only if there is a dot following the previous match:
andy mypass ok orange..see what is going on
The matched text here would be orange (Because there was a dot after “orange”, ah yes, and many spaces before).
“Assert that it is impossible to match the regex below starting at this position”.
The regex changes to:
Do you see the difference?. this should read now:
Match a space between one and many times followed by a word character between one and many times only if the following character is not a dot, so what is matched now using our previous.
mypass (Because after "mypass" was a space) ok (Same reason using the word "ok") orang (Because after "orang" there is an e) see (Because after "see" there is a space)
…. and so on