(Ruby) Character literal notation not supported for some cases

Describe the issue Only some cases of Character Literals seem to be supported. Support is missing for the following groups of cases (in decreasing importance):

• Single slash character (?/), breaks following lines as it gets treated as starting a regex
• Escaped backslash character (?\\)
• Non-ascii character (?あ)
• Unicode using curly-bracket notation (?\u{1AF9})
• Control and Meta characters (?\C-a)

Which language seems to have the issue? ruby

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Sample Code to Reproduce

c = ?a       #=> "a"
c = ?abc     #=> SyntaxError
c = ?\n      #=> "\n"
c = ?\s      #=> " "
c = ?\\      #=> "\\"
c = ?\u{41}  #=> "A"
c = ?\C-a    #=> "\x01"
c = ?\M-a    #=> "\xE1"
c = ?\M-\C-a #=> "\x81"
c = ?\C-\M-a #=> "\x81", same as above
c = ?あ      #=> "あ"


c = ?/          #=> /
c = ?\123       # octal bit pattern, where nnn is 1-3 octal digits ([0-7])
c = ?\xA1       # hexadecimal bit pattern, where nn is 1-2 hexadecimal digits ([0-9a-fA-F])
c = ?\uAF09     # Unicode character, where nnnn is exactly 4 hexadecimal digits ([0-9a-fA-F])
c = ?\cx        # control character, where x is an ASCII printable character
c = ?\c\M-x     # meta control character, where x is an ASCII printable character
c = ?\c?        # delete, ASCII 7Fh (DEL)
c = ?\C-?       # delete, ASCII 7Fh (DEL)

Expected behavior

Additional context Seen in this StackExchange/CodeGolf answer: https://codegolf.stackexchange.com/a/217367/25026

->(n,g=->c,d{(1..n).map{|i|" "*(n-i)+d+" "*2*(n+i-1)+c}},l=g[?/,e=?\\].reverse){[" "*n+?_*n*2,g[e,?/],l[0..-2],l[-1].sub(/ +(?=\/)/,?_*n*2)]}

[joshgoebel]

Ah, but that character does not form a word boundary so \b will abort the match.

If we’re going to fix this we need variants, not one big regex. 😃

[Hirse]

\S seems to match unicode: https://regexr.com/5jodu