Raw string literals in .NET, both useful and entertaining

#programming #c #net

Original post: https://siderite.dev/blog/raw-string-literals-in-net-both-useful-and-enterta

Intro

Another new feature in .NET that I absolutely love: Raw string literals, optionally followed by a new_line, the content of the string, and then ends with the same number of quotes that the literal started with. ").

You probably know about normal strings: they start with a double quote and end with a double quote and every special character, including a double quote, has to be escaped with a backslash. You also know about verbatim strings: they start with @ and then a double quote and can contain any string, including new line characters, with the only exception being the double quote character which must be doubled to be escaped. Great for JSON with single quotes, not so great for XML, for example, but still better than escaping everything with slashes. You might even know about interpolated strings, starting with a $ and supporting templates. I wrote a blog post about it. It can be used with all the other types of strings.

If you worked with markup language - used in web rich text editors and blogs and instant messengers - you might have used a special syntax for indicating "blocks of code". You do it by enclosing a line of code with backticks (`) or by using three backticks, followed by a new line, then multiple lines of code, then three other backticks to close the block. You can even use something like three backticks followed by "csharp" to indicate that the syntax highlighting is supposed to be for C#.

Well, this feature has finally been added to C# itself, just that instead of backticks you use double quotes and you use a // lang = ... comment above it to declare the highlighting - even if Visual Studio and other editors know to recognize common structures like XML and JSON and stuff like that.

Details

This is great for so many things, but I love that it improves readability and allows syntax checking of the content. Check this out:

I specified that this is Regex, so it automatically warned me that I missed a closing parenthesis.

It's really cool for XMLs:

Although for some reason it didn't do syntactic highlighting, look how nice it looks: no doubled or escaped double quotes. You can read the XML, you can copy paste it as it is. This is a thing of beauty. Also, note that the whitespace between the content and the literal string block delimiters is ignored! This didn't happen with verbatim strings, much to my chagrin. In the example above, the first character of the resulting string is less-than (<) and the last is greater-than (>)

But wait... what happens if you want to have three double quotes in the literal string? Why? Because you can. Did you find the Achilles heel for literal strings? No! Because you can have a minimum of three double quotes to declare a literal string. You want three double quotes in the literal? Fine, start and end the literal string with four double quotes!

This leave me to the example in the first image. One can use a ton of double quotes that will not only declare a literal string, but also visually delimit it from the surrounding text. This is the future! If you have more string content than double quotes, something must be really wrong.