Best delimiter to separate multipe regex

Question

I need to put multiple regular expressions in a single string and then parse it back as separate regex. Like below

regex1<!>regex2<!>regex3

Problem is I am not sure which delimiter will be best to use to separate the expressions in place of <!> shown in example, so that I can safely split the string when parsing it back.

Constraints are, I can not make the string in multiple lines or use xml or json string. Because this string of expressions should be easily configurable.

Looking forward for any suggestion.

Edited:

Q: Why does it have to be a single string?

A: The system has a configuration manager that loads config from properties file. And properties are containing lines like

com.some.package.Class1.Field1: value
com.some.package.Class1.Expressions: exp1<!>exp2<!>exp3

There is no way to write the value in multiple lines in the properties file. That's why.

Answer 1

The best way would be to use invalid regex as delimiter such as ** Because if it is used in normal regex it won't work and would throw an exception{NOTE:++ is valid}

regex1+"**"+regex2

Now you can split it with this regex

(?<!\\\\)[*][*](?![*])
-------         -----
   |              |->to avoid matching pattern like "A*"+"**"+"n+"
   |->check if  * is not escaped

---

Following is a list of invalid regex

• [+
• (+
• [*
• (*
• [?
• *+
• ** (delimiter would be (?<!\\\\)[*][*](?![*]))
• ??(delimiter would be (?<!\\\\)[?][?](?![?]))

While splitting you need to check if they are escaped

(?<!\\\\)delimiter