Add string escaping according to string regex format

[thexa4]

Based on:

KOS/src/kOS.Safe/Compilation/KS/kRISC.tpg

Line 91 in b56c1b5

STRING -> @"@?\""(\""\""|[^\""])*\""";

Fixes #2672

(Warning: has not been tested yet, unable to compile right now)

[jonnyboyC]

@Dunbaratu Does this now allow certain string escapes? Could you give an example? Mostly just trying to keep https://github.com/jonnyboyC/kos-language-server as in sync with master here a possible

[thexa4]

It makes print "hello""world". output hello"world

[jonnyboyC]

Thanks!

[7ranceaddic7]

@thexa4 Is that really the desired result?

I would think that output should be hello""world, no?

[thexa4]

The advantage of treating a repeated quote as a single quote is that it allows you to represent all strings. If you use it as-is, you would not be able to write down a string literal that only contains ".

The way this is usually solved is by defining an escape character like \. "\"" would then become a " string literal. The other option is escaping by repeating the character. An example of this is printf. It uses the % character to as a field placeholder. This makes it impossible to print a string that contains an actual % character. The solution they use interprets a %% as a single literal %.

The existing parser syntax seems a lot like the printf case which is why I used this behavior.