is_ignored_output function

[John W. Eaton]

On  2-Aug-2010, Rik wrote:

| 1) Remove initial '_'
| 
| Octave has been moving from "is_XXXXX" to "isXXXXX", for example,
| "is_global" to "isglobal".

That was generally for compatibility with Matlab.

Emacs Lisp has a convention for this kind of thing that I like, which
is that if the word/phrase has underscores, use an underscore in the
predicate formed from the word/phrase, otherwise don't.  So we would
write isused and is_used_output instead of is_used and isused_output
(though with Emacs, the convention is also be to append a p instead of
prefix with is: usedp and used_output_p instead of used_p or
usedoutput_p).

jwe