Support Infinite hash raw strings

[RedCMD]

fixes #3

• Raw string literals (more than one #, grammar limitations prevent us from supporting escapes) #3

only a few hundred files with more than one #
https://github.com/search?q=lang%3Aswift+%2F%23%23%2B%22%22%22%2F&type=code

[RedCMD]

I noticed your comment
Allow \("""...""") to appear inside a block string
I assume this won't apply for raw strings? #"""\#(#"""..."""#)"""#
because the starting and ending delimiters are different?

[jtbandes]

I assume this won't apply for raw strings? #"""\#(#"""..."""#)"""# because the starting and ending delimiters are different?

I'm not quite sure I understand which scenario you are asking about, but I believe all the nesting options are valid. In your example, some of the " are part of the string since it's not actually a multi-line string.

https://godbolt.org/z/W71MEWcaa

I think the point of the comment/rule you pointed out is: usually [something]""" is not allowed for multi-line strings (the closing delimiter should be on its own line) however, actually \###(""" is okay since that starts a string interpolation.

Honestly, I'm not sure if keeping the invalid.illegal rules is really worth it 🤷 It was a convention I inherited from other TextMate grammars, but generally highlighting valid code seems much more important than highlighting invalid code.

[RedCMD]

Refactored it again
supports infinite hash raw strings
added more tests
added a Markdown test example
made single-line strings end at eol $ and mark the last char as invalid invalid.illegal.returns-not-allowed.swift

I'm pretty happy with it now

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only issue I know is that if theres an invalid escape (thats too big)
the grammar will then 'forget' how many hashes # it was tracking and just assume the next escape is correct
so it thinks \#n is a valid escape here (because \###a is a too big invalid escape)

##"""
\###a
\#n
"""##

could add a hardcoded #""" ... """# rule so that single # raw strings always work 100% of the time

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I revisited this after coming from here:

• Semantic highlighting does not distinguish escaped characters in string literals swiftlang/sourcekit-lsp#2472