How to find this using Regular Expression?

Question

I thought I understood C# regular expressions, but clearly it's not the case. I need some help devising an expression that would find everything from START|BEGIN until )). Expression can be multi line.

Ex.

START( FTP_STATE, XXX(
   VAL( FTP_INITIAL_STATE, 0 )
   VAL( FTP_INBOUND,       1 )
   AL( FTP_OUTBOUND,      2 )
))

/**************************************************************/

BEGIN( FTP_TIMER_MODE, YYY(
   VAL( FTP_REMOVE_TIMER,     0 )
   VAL( FTP_NOT_REMOVE_TIMER, 1 )
))

/**************************************************************/

Any help greatly appreciated

Answer 1

It is straight forward; START or BEGIN, then any number of any symbol but non greedy and finaly the two closing parenthesis. .*? takes any number of any symbol, but as few as possible. To match over more then one line the single line option (?s) must be enabled (Thanks Alan M. for pointing that out.)

(?s)(START|BEGIN).*?\)\)

Answer 2

I don't know the syntax for C#, but in Perl it's:

m/(BEGIN|START).*?\)\)/s

The s makes it multiline.

You just have to see how to make the regex multiline in C#

Answer 3

If you don't understand, and want to learn, regexps then let me recommend this regexp site

The solution is probably something like /(START|BEGIN).*))/

Answer 4

Try this:

(?:START|BEGIN)(?:[^)]+|\)[^)])+\)\)

To explain it:

• (?:START|BEGIN)   Start with either START or BEGIN.
• (?:[^)]+|\)[^)])+    After that either any character other than a ) ([^)]+) or a ) that is followed by any character other than ) (\)[^)]) may follow. (So there is no way to match )) with this expression.)
• \)\)   Finally the )).

I hope this will reduce backtracking.

Answer 5

Actually you need to account for the VAL( ... )'s as well.

In perl it would be:

(BEGIN|START)\([^(\)\)\))].+\)\)\)

1. Starts with BEGIN or START
2. Has a opening bracket
3. Allows anything NOT ))) in between, to avoid greedy matching
4. Ends with three closing brackets )))

Answer 6

ResultString = Regex.Match(subject, @"(START|BEGIN).*?\)\)", RegexOptions.Singleline).Value;

Answer 7

Try this

MatchCollection m = Regex.Matches(input, "(START|BEGIN).+?\\)\\)", RegexOptions.Multiline);

Answer 8

@"(?s)(?:START|BEGIN).*?\)\)"

What some of the others are calling "multiline mode" is actually single-line (or DOTALL) mode. That's the mode that lets the dot match newlines. Multiline mode lets '^' match the beginning of a line '$' match the end of a line (normally, the only match the start and end of the whole string. I'm using DOTALL mode with the inline modifier "(?s)".

Answer 9

You've already got your answer but I thought I'd throw in this link which I find very useful for building/testing expressions. You can quickly test things out and then paste the expression into your code when you're satisfied with it.