+
+% PDF uses PostScript string constants for the names of xref targets,
+% for display in the outlines, and in other places. Thus, we have to
+% double any backslashes. Otherwise, a name like "\node" will be
+% interpreted as a newline (\n), followed by o, d, e. Not good.
+% http://www.ntg.nl/pipermail/ntg-pdftex/2004-July/000654.html
+% (and related messages, the final outcome is that it is up to the TeX
+% user to double the backslashes and otherwise make the string valid, so
+% that's what we do).
+
+% double active backslashes.
+%
+{\catcode`\@=0 \catcode`\\=\active
+ @gdef@activebackslashdouble{%
+ @catcode`@\=@active
+ @let\=@doublebackslash}
+}
+
+% To handle parens, we must adopt a different approach, since parens are
+% not active characters. hyperref.dtx (which has the same problem as
+% us) handles it with this amazing macro to replace tokens. I've
+% tinkered with it a little for texinfo, but it's definitely from there.
+%
+% #1 is the tokens to replace.
+% #2 is the replacement.
+% #3 is the control sequence with the string.
+%
+\def\HyPsdSubst#1#2#3{%
+ \def\HyPsdReplace##1#1##2\END{%
+ ##1%
+ \ifx\\##2\\%
+ \else
+ #2%
+ \HyReturnAfterFi{%
+ \HyPsdReplace##2\END
+ }%
+ \fi
+ }%
+ \xdef#3{\expandafter\HyPsdReplace#3#1\END}%
+}
+\long\def\HyReturnAfterFi#1\fi{\fi#1}
+
+% #1 is a control sequence in which to do the replacements.
+\def\backslashparens#1{%
+ \xdef#1{#1}% redefine it as its expansion; the definition is simply
+ % \lastnode when called from \setref -> \pdfmkdest.
+ \HyPsdSubst{(}{\realbackslash(}{#1}%
+ \HyPsdSubst{)}{\realbackslash)}{#1}%
+}
+