'unique' error message is printed despite silent=TRUE (PR#13547)

Peter Dalgaard wrote:

macrakis at alum.mit.edu wrote:

<snip>

try(.Internal(unique(quote(hello),NULL,NULL)),silent=TRUE)

hello

I guess it is using the internal equivalent of print rather than the
internal equivalent of stop.

silent=TRUE is a red herring (this has nothing to do with try()).

However, inside do_duplicated (unique.c) we have

    if (!isVector(x)) {
    PrintValue(x);
    error(_("%s() applies only to vectors"),
          (PRIMVAL(op) == 0 ? "duplicated" : "unique"));
    }

This is due to

------------------------------------------------------------------------
r32306 | ripley | 2004-12-23 22:06:27 +0100 (Thu, 23 Dec 2004) | 2 lines

Apparently unique/duplicated are supposed to work on NULL, despite
their help!

...which makes little sense to explain the PrintValue(x). I suspect
this is a debugging printout that was inadvertently left in.

hmm, why wouldn't you use something like

    DEBUG(x)

with DEBUG being a macro defined so that it's replacement is void unless
a specific flag or environment variable is set specifically for the
purpose of debugging?  you would then avoid confusing users' code just
because one PrintValue has been inadvertently left in the sources.