using System;
using System.Text.RegularExpressions;
public class Example
{
public static void Main()
{
string pattern = @"(?P<nested>
\b if \b
(?P<if>(?>.?(?>(?P>nested))?)*?)
(?:
\b elsif \b
(?P<elsif>(?>.?(?>(?P>nested))?)*?)
)?
(?:
\b else \b
(?P<else>(?>.?(?>(?P>nested))?)*?)
)?
\b endif \b
)?
";
string input = @"if
1
if
2
elsif
2
else
2
if
3
endif
2
endif
1
if
2
else
2
endif
1
elsif
1_elsif1_
elsif
1_elsif2_
else
1_else_
endif";
RegexOptions options = RegexOptions.IgnoreCase | RegexOptions.IgnorePatternWhitespace | RegexOptions.Singleline;
Match m = Regex.Match(input, pattern, options);
Console.WriteLine("'{0}' found at index {1}", m.Value, m.Index);
}
}
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for C#, please visit: https://msdn.microsoft.com/en-us/library/system.text.regularexpressions.regex(v=vs.110).aspx