Subject: Re: [boost] [Regex] Why doesn't this pattern match?
From: Vitalij Gotovskij (Vitalij.gotovskij_at_[hidden])
Date: 2009-12-08 06:07:51
>> Yes, Robert, You are right. I am trying to change \\n (wchar_t '\' and
>> wchar_t 'n') with a real new line symbols and it doesn't work. Allthought,
>> then I am trying to find only wchar_t 'n' (or any other letter) everything
>> is working good. The problem is that I have XML configuration file
>> (Unicode), where all new lines are L"\\n" (!!! not '\n' !!!). I can't
>> change that file format. Of course I can program that replace without
>> boost::regex, but I am afraid that I'll loose my sleep afterwards...
>>>> You're replacing each occurrence of \\n with \\n, so the
>>>> string at the end should be exactly the same! :-)
>>> The replacement is "\n" not "\\n" so the '\' followed by 'n' in str
>>> should be replaced with a newline, right?
> No. Remember the compiler gets first bite at the escape characters, so if
> you put a string "\\n" in your program, that gets passed to Boost.Regex as
> the two character string: "\n", which matches a single newline character.
> If you want to match a \ followed by a \n then you need a regex of "\\\n".
You wanted to say: "\\\\n" ? :) Anyway, thanks a lot. This works!
Didn't knew regex engine is working in that way... If he understands "\\\\n" as C++ "\\n"
and "\\n" as C++ understands "\n", then how regex engine understands "\n" ...?
Don't answer this letter. The problem is solved.
Boost list run by bdawes at acm.org, gregod at cs.rpi.edu, cpdaniel at pacbell.net, john at johnmaddock.co.uk