FINNISH sections, use the regex (?s-i).*?\KSTART.+?FINNISH(?=.*\Z).FINNISH section, use the regex (?s-i)\A.*\KSTART.+?FINNISH(?=.*\Z).FINNISH section, use the regex (?s-i)\A.*?\KSTART.+?FINNISH(?=.*\Z).FINNISH section is rather easy ! To search for :.FINNISH section for this specific file and vice-versa !.Note that changing, LATER, the Y letter ( Yes ) to the N letter or anything else, in an HTML file, would not trigger the search of a START So, we could change the last line into the line with this regex S/R Thus, the sole practical and easy solution is to place an specific indicator at the very end of current document, which can be noticed with an look-ahead, and, for instance, the syntax (?=.*indicator\z)Īs you deal with HTML, I suppose that a comment after the last tag, is allowed by the language ? This is absolutely not what is expected ! Unfortunately, and unlike programs and scripts, the regex groups and subroutines calls cannot be stored over two consecutive search processes ! As the group 1 is not defined, this empty ELSE part simply matches an empty string at the location right after the FINNISH word and in all the subsequent locations till the end of file ! Note that this regex is equivalent to the regex (?(1).*?\KSTART.+?FINNISH|) with an empty ELSE part. Thus the second alternative (?(1).*?\KSTART.+?FINNISH) is processed.
Moreover, this first alternative is canceled due to the (*F) syntax So, the regex engine goes on processing the overall regex :Ĭurrent position is obviously not at the very beginning of file, so the first alternative cannot match and the group 1 is not defined.
However, let’s imagine that the current file contain a second START *?), forgotten because of the \K syntax, and, finally, looks for and finds the first START So, still from the very beginning of file, it looks for minimum stuff (. So, due to the (*F) syntax, the regex engine switches to the next alternative (?(1).*?\KSTART.+?FINNISH) which is a conditional expression that is true ONLY IF group 1 exists. Note that, at the end, the control verb (*F) cancels the current alternative but, luckily, does not reset the group 1 So, now, the group 1 is defined as BABY SIN.
The regex engine tests the first alternative (?s-i)(?=\A.*?(BABY SIN))(*F) and match an empty string if the string BABY SIN exists. So, when the regex engine is right before the first char of current file : Or course, there’s a simple solution, used many times in regex topics ! Before speaking about it, in the second part of this post, I also considered the possibility to catch the BABY SIN string with this kind of regex : So, one the BABY SIN location is over, there no means for the regex engine to remember that current file contains that specific string :-((
The general problem is that the regex engine always searches from the left to the right.
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