Dylan: add operator escapes and string hex escapes

[jneen]

See discussion at #2248, cc @pedro-w

[pedro-w]

I will check ASAP!

[jneen]

Added an image of the rendered text.

[jneen]

Should inline be covered here as well? It's always a bit hard in a super dynamic-syntax language like dylan to know where to start and stop with keyword highlighting.

[pedro-w]

The modifiers between define and method can be any non-reserved word. It's a personal preference but I'd say it's useful to keep them as they are in a contrasting colour rather than matching the formatting of define, even if its not so aesthetically pleasing.

[pedro-w]

Looking through dylan's own codebase as it contains some hairy stuff...

https://github.com/dylan-lang/opendylan/blob/85fc782bf2b1390929bdb9fc98f88e5e55d7a742/sources/io/format-condition.dylan#L9-L20

define sideways method print-object (c :: <condition>, s :: <stream>) => ()
  let message = condition-to-string(c);
  if (*print-escape?* | ~message)
    printing-object (c, s)
      if (message)
        format(s, ": %s", message)
      end
    end
  else
    write(s, message)
  end
end method print-object;

Here the ~ is not matched. (it's a "UNARY-OPERATOR" in the DRM, it means "logical not")

[pedro-w]

% git diff
diff --git a/lib/rouge/lexers/dylan.rb b/lib/rouge/lexers/dylan.rb
index d019229a..0d0208b6 100644
--- a/lib/rouge/lexers/dylan.rb
+++ b/lib/rouge/lexers/dylan.rb
@@ -71,7 +71,7 @@ module Rouge
         rule %r/#x[0-9a-f]+/i, Literal::Number::Hex
 
         # Operators and punctuation
-        rule %r/::|=>|#[(\[#]|[.][.][.]|[(),.;\[\]{}=?]/, Punctuation
+        rule %r/~|::|=>|#[(\[#]|[.][.][.]|[(),.;\[\]{}=?]/, Punctuation
 
         word_re = %r([\w!&*<>|^\$%@][\w!&*<>|^\$%@=/?~+-]*|[+-])

Maybe? I should leave it to the professionals 😉

[jneen]

I put it in word_re instead, as it seems like it's classified as a word operator, presuming you can also do \~ to refer to it as a symbol.