On 4/19/06, <b class="gmail_sendername">Greg Ewing</b> <<a href="mailto:greg.ewing@canterbury.ac.nz">greg.ewing@canterbury.ac.nz</a>> wrote:<div><span class="gmail_quote"></span><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
Edward C. Jones wrote:<br><br>> I suggest a singleton object "UseForbidden" ("Py_UseForbidden" in C).<br><br>It should be called "Mu". :-)<br><br>Although such an object could cause a lot of pain to
<br>debuggers and other such introspective code.<br></blockquote></div><br>Actually this sounds a lot like a signaling Not-a-number (sNaN) from IEEE754. One can pass around a sNaN, but any use will raise a (numeric) exception. Similarly, you want a signaling Not-an-Object (sNaO) that also doesn't like to be passed as a function argument. It is the last bit that makes it a pain, since what if your function is log_error_value(sNaO)?
<br><br>-Kevin<br><br>