fork download
copy 
  1. using System;
  2. using System.Linq;
  3. using System.Text.RegularExpressions;
  4.  
  5. namespace ConsoleApplication1
  6. {
  7.     public class Program
  8.     {
  9.         public static void Main(string[] args)
  10.         {
  11.             var implicitParenRegexes = @"
  12. (a)(?(?=.) )(b) (c)
  13. (a)(?(?!z) )(b) (c)
  14. (a)(?(?<=.) )(b) (c)
  15. (a)(?(?<! ) )(b) (c)
  16. (a)(?(?: ) )(b) (c)
  17. (a)(?(?i:.) )(b) (c)
  18. (a)(?(?>.) )(b) (c)
  19. (a)(?(?(1).) )(b) (c)
  20. ((?<n>a))(?(?(n).) )(b)(c)
  21. (a)(?(?(?:.).) )(b) (c)
  22. (a)(?(?<n>.) )(b) (c)
  23. (a)(?(?'n'.) )(b) (c)
  24. (a)(?(?'-n' .) )(b) (c)
  25. (?<a>a)(?(?<a-n>.) )(b) (c)
  26. (a)(?(?# comment) )(b) (c)
  27. (a)(?(?i) )(b) (c)
  28. (a)(?(?(.).) )(b) (c)
  29. ".Split(new char[] { '\r', '\n' }, StringSplitOptions.RemoveEmptyEntries);
  30.             var explicitParenRegexes = @"
  31. (a)(?((?=.)) )(b) (c)
  32. (a)(?((?!z)) )(b) (c)
  33. (a)(?((?<=.)) )(b) (c)
  34. (a)(?((?<! )) )(b) (c)
  35. (a)(?((?: )) )(b) (c)
  36. (a)(?((?i:.)) )(b) (c)
  37. (a)(?((?>.)) )(b) (c)
  38. (a)(?((?(1).)) )(b) (c)
  39. ((?<n>a))(?((?(n).)) )(b)(c)
  40. (a)(?((?(?:.).)) )(b) (c)
  41. (a)(?((?<n>.)) )(b) (c)
  42. (a)(?((?'n'.)) )(b) (c)
  43. (a)(?((?'-n' .)) )(b) (c)
  44. (?<a>a)(?((?<a-n>.)) )(b) (c)
  45. (a)(?((?# comment)) )(b) (c)
  46. (a)(?((?i)) )(b) (c)
  47. (a)(?((?(.).)) )(b) (c)
  48. ".Split(new char[] { '\r', '\n' }, StringSplitOptions.RemoveEmptyEntries);
  49.  
  50.             Console.WriteLine("IMPLICIT PARENTHESIZED CONDITIONS:");
  51.             foreach (var pattern in implicitParenRegexes)
  52.                 CheckPattern(pattern);
  53.  
  54.             Console.WriteLine("\nEXPLICIT PARENTHESIZED CONDITIONS:");
  55.             foreach (var pattern in explicitParenRegexes)
  56.                 CheckPattern(pattern);
  57.  
  58.             Console.ReadKey();
  59.         }
  60.  
  61.         const string input = "a b c";
  62.         static void CheckPattern(string pattern)
  63.         {
  64.             Console.Write("Regex: '{0}'; groups: ", pattern);
  65.  
  66.             // Comment this block to get the exception
  67.             if (pattern.Contains("(?(?i)"))
  68.             {
  69.                 Console.WriteLine("Skipped to allow it run in ideone");
  70.                 return;
  71.             }
  72.  
  73.             try
  74.             {
  75.                 int index = 1;
  76.                 Console.WriteLine(string.Join("; ", 
  77.                     Regex.Match(input, pattern).Groups.Cast<Group>().Skip(1).Take(3)
  78.                         .Select(g => string.Format("${0}: '{1}'", index++, g.Value))));
  79.             }
  80.             catch (Exception exception)
  81.             {
  82.                 Console.WriteLine("ERROR: {0}: {1}", exception.GetType().Name, exception.Message);
  83.             }
  84.         }
  85. 	}
  86. }
Success #stdin #stdout 0.04s 30280KB
comments (?)
stdin
copy 
Standard input is empty
stdout
copy 
IMPLICIT PARENTHESIZED CONDITIONS:
Regex: '(a)(?(?=.) )(b) (c)'; groups: $1: 'a'; $2: 'c'; $3: ''
Regex: '(a)(?(?!z) )(b) (c)'; groups: $1: 'a'; $2: 'c'; $3: ''
Regex: '(a)(?(?<=.) )(b) (c)'; groups: $1: 'a'; $2: 'c'; $3: ''
Regex: '(a)(?(?<! ) )(b) (c)'; groups: $1: 'a'; $2: 'c'; $3: ''
Regex: '(a)(?(?: ) )(b) (c)'; groups: $1: 'a'; $2: 'c'; $3: ''
Regex: '(a)(?(?i:.) )(b) (c)'; groups: $1: 'a'; $2: 'c'; $3: ''
Regex: '(a)(?(?>.) )(b) (c)'; groups: $1: 'a'; $2: 'c'; $3: ''
Regex: '(a)(?(?(1).) )(b) (c)'; groups: $1: 'a'; $2: 'c'; $3: ''
Regex: '((?<n>a))(?(?(n).) )(b)(c)'; groups: 
Regex: '(a)(?(?(?:.).) )(b) (c)'; groups: $1: 'a'; $2: 'c'; $3: ''
Regex: '(a)(?(?<n>.) )(b) (c)'; groups: ERROR: ArgumentException: parsing '(a)(?(?<n>.) )(b) (c)' - Alternation conditions do not capture and cannot be named.
Regex: '(a)(?(?'n'.) )(b) (c)'; groups: ERROR: ArgumentException: parsing '(a)(?(?'n'.) )(b) (c)' - Alternation conditions do not capture and cannot be named.
Regex: '(a)(?(?'-n' .) )(b) (c)'; groups: ERROR: ArgumentException: parsing '(a)(?(?'-n' .) )(b) (c)' - Alternation conditions do not capture and cannot be named.
Regex: '(?<a>a)(?(?<a-n>.) )(b) (c)'; groups: ERROR: ArgumentException: parsing '(?<a>a)(?(?<a-n>.) )(b) (c)' - Alternation conditions do not capture and cannot be named.
Regex: '(a)(?(?# comment) )(b) (c)'; groups: ERROR: ArgumentException: parsing '(a)(?(?# comment) )(b) (c)' - Alternation conditions cannot be comments.
Regex: '(a)(?(?i) )(b) (c)'; groups: Skipped to allow it run in ideone
Regex: '(a)(?(?(.).) )(b) (c)'; groups: $1: 'a'; $2: 'b'; $3: 'c'

EXPLICIT PARENTHESIZED CONDITIONS:
Regex: '(a)(?((?=.)) )(b) (c)'; groups: $1: 'a'; $2: 'b'; $3: 'c'
Regex: '(a)(?((?!z)) )(b) (c)'; groups: $1: 'a'; $2: 'b'; $3: 'c'
Regex: '(a)(?((?<=.)) )(b) (c)'; groups: $1: 'a'; $2: 'b'; $3: 'c'
Regex: '(a)(?((?<! )) )(b) (c)'; groups: $1: 'a'; $2: 'b'; $3: 'c'
Regex: '(a)(?((?: )) )(b) (c)'; groups: $1: 'a'; $2: 'b'; $3: 'c'
Regex: '(a)(?((?i:.)) )(b) (c)'; groups: $1: 'a'; $2: 'b'; $3: 'c'
Regex: '(a)(?((?>.)) )(b) (c)'; groups: $1: 'a'; $2: 'b'; $3: 'c'
Regex: '(a)(?((?(1).)) )(b) (c)'; groups: $1: 'a'; $2: 'b'; $3: 'c'
Regex: '((?<n>a))(?((?(n).)) )(b)(c)'; groups: 
Regex: '(a)(?((?(?:.).)) )(b) (c)'; groups: $1: 'a'; $2: 'c'; $3: ''
Regex: '(a)(?((?<n>.)) )(b) (c)'; groups: $1: 'a'; $2: 'b'; $3: 'c'
Regex: '(a)(?((?'n'.)) )(b) (c)'; groups: $1: 'a'; $2: 'b'; $3: 'c'
Regex: '(a)(?((?'-n' .)) )(b) (c)'; groups: ERROR: ArgumentException: parsing '(a)(?((?'-n' .)) )(b) (c)' - Reference to undefined group name n.
Regex: '(?<a>a)(?((?<a-n>.)) )(b) (c)'; groups: ERROR: ArgumentException: parsing '(?<a>a)(?((?<a-n>.)) )(b) (c)' - Reference to undefined group name n.
Regex: '(a)(?((?# comment)) )(b) (c)'; groups: $1: 'a'; $2: 'b'; $3: 'c'
Regex: '(a)(?((?i)) )(b) (c)'; groups: $1: 'a'; $2: 'b'; $3: 'c'
Regex: '(a)(?((?(.).)) )(b) (c)'; groups: $1: 'a'; $2: 'b'; $3: 'c'
https://ideone.com/KHbqMI
language:
C# (gmcs 5.20.1)
created:
7 years ago
visibility:
public

Share or Embed source code

Discover > Sphere Engine API

The brand new service which powers Ideone!

Discover > IDE Widget

Widget for compiling and running the source code in a web browser!