Uses ICU facilities to unescape Unicode character sequences.
The following ASCII standard escapes are recognized:
\a
, \b
, \t
, \n
, \v
, \?
,
\e
,
\f
, \r
, \"
, \'
, \\
.
Moreover, the function understands the following ones:
\uXXXX
(4 hex digits),
\UXXXXXXXX
(8 hex digits),
\xXX
(1-2 hex digits),
\ooo
(1-3 octal digits),
\cX
(control-X; X is masked with 0x1F).
For \xXX
and \ooo
beware of non-valid UTF8 byte sequences.
Note that some versions of R on Windows cannot handle
characters defined with \UXXXXXXXX.
We are working on that.