Bug in Match Pattern in LabVIEW 2010

[rolfk]

I seem to have found a bug in MatchPattern in LabVIEW 2010 when upgrading code from LabVIEW 8.2.1. Please refer to attached snippet to see more of the details.

With an input string of "RDB\tE\n..." and a search pattern of "[^\r\n]+" I would expet the result to be "RDB\tE" but it really is simply "RDB". This is quite a serious bug as it can render many string syntax parsers invalid. Of course PCRE is a workaround for now, but the help of the PCR function says explicitedly that it is slower in performance than the Match Pattern function.

Windows XP SP3, LabVIEW 2010 SP1

[Darin.K]

Correct me if I am wrong, but I believe the [^] construct in Match Pattern returns displayable characters, of which \t is not.

My opinion is annoying, but not a bug in LV10.  Certainly going to bite someone in the arse.  Particularly nasty that it worked (incorectly) in LV8.2 apparently, I hate bug "fixes" that fix bugs you had no idea existed. 

Personally, I have bitten the bullet and use PCRE almost exclusively.

I agree there is a bug here, a LV8.2 bug.

[Darin.K]

By the way the [~] construct also returns non-displayable characters, this is what you should be using here.

Half of the time I foul up my PCRE regexes by screwing up the ^ and ~, one reason I am starting to stick to one.

[rolfk]

Match Pattern is Regex similar but not the same. This is what the online help in LabVIEW 7.1 had to say about the ^ character when in brackets:

^	Matches any displayable character, including the space and tab characters, except the characters or range of characters enclosed in the brackets. For example, [^0-9] matches all displayable characters, including the space and tab characters, except 0 through 9.

Emphasis is mine.

So I still believe it is a bug in 2010!

[Darin.K]

LV9 Help for ^ inside []:

Matches any displayable character, including the space character, except the characters or range of characters enclosed in the brackets. For example, [^0-9] matches all displayable characters, including the space character, except 0 through 9.

Lack of emphasis shows lack of 'tab'.

I agree that it is devious to change behavior, but it is hard to say bug when the behavior matches the documentation.  That is usually all I ask.

[rolfk]

Yes I just checked. Seems the documentation was changed in LabVIEW 8.2 and then the functionality was changed to match the documentation in 8.5. And devious it is for sure!!