Steps required to reproduce the problem

1. Look at the RegexBuilder class.
2. Look at the RegexBuilder::delimiter method, it calls the Regexer\Syntax\Delimiter::getOpeningAndClosingDelimiter() method
3. Look at the Regexer\Syntax\Delimiter class
4. The Regexer\Syntax\Delimiter::getOpeningAndClosingDelimiter() method is undefined

Expected Result

• Executing the unit test is successful

Actual Result

• The unit test is failed.

This means setters for all nodes, and tests.

(abc|def)=\1 matches abc=abc or def=def, but not abc=def or def=abc

Notation can be

• \1
• \g1
• \g{1}

e.g
/fo{2}/

matches foo, not fofo.

Same as normal ones, but negative e.g \g{-2}

(?<name>regex)
(?'name'regex)
(?P<name>regex)

'normal' delimiters are closed again by the same character.

But you can also use [, { and (, which will be closed by their correspoding chacater (], } and )).

If you use ) as the opening delimiter, then the closing one will also be ).

[[:digit:][:lower:]] matches one of 0 through 9 or a through z

(?#comment)

Everything between (?# and ) is ignored by the regex engine.

`/foo|ba[rz]/

Should be

• Or
  • foo
  • Group(
    • ba
    • [rz]
  • end of group
• end of or

But right now its

• Or
  • foo
  • ba
• end of or
• [rz]

• \k
• \k'name'
• \k{name}
• \g{name}
• (?P=name)