I'm trying to write pattern to recognize formula IF form string.

e.g. string

[@param_6@]  @IF(@param_5@==null;@param_5@;@IF(1==1;@param_2@;@param_4@)@)@ - @param_3@ - <@IF(@parameter_tag2@ == null;@param_4@;@param_5@)@>

I want to obtain this result

1. Match: @IF(@param_5@==null;@param_5@;@IF(1==1;@param_2@;@param_4@)@)@
2. Match: @IF(@parameter_tag2@ == null;@param_4@;@param_5@)@

My pattern look like:

@IF\(.*\;.*\;.*\)@

But regex return me wrong result.

CodePudding user response：

You can use

(?s)@IF\((?>(?!@IF\(|\)@).|(?<o>)@IF\(|(?<-o>)\)@)*\)@

See the regex demo. Details:

• (?s) - RegexOptions.Singleline equivalent, . now matches LF chars, too
• @IF\( - a @IF( string
• (?>(?!@IF\(|\)@).|(?<o>)@IF\(|(?<-o>)\)@)* - zero or more repetitions of
  • (?!@IF\(|\)@).| - any char that does not start a @IF( or )@ char sequence
  • (?<o>)@IF\(| - a @IF( substring and a value is pushed on to the "o" group stack, or
  • (?<-o>)\)@ - a )@ string and a value is popped from the "o" group stack
• \)@ - a )@ string