Subject: RE: 23.0.93; doc string of set-frame-parameter

From: "Drew Adams" <[email-masked]>
Date: Thu, 14 May 2009 00:43:42 -0700

> From: Chong Yidong Sent: Wednesday, May 13, 2009 8:28 PM
> > "If FRAME is nil, it defaults to the selected frame."
> > 
> > No. If FRAME is nil, then there is no argument defaulting. It should
> > say that if FRAME is nil, the selected frame is used.
> 
> This is standard usage in many docstrings.  There is no risk of
> confusion.

What is "standard usage in many doc strings" is to say that by default, the
selected frame is used, where "by default" refers to the _absence_ of an
optional arg. There is no optional argument here.

This is not just about possible confusion; it's about English and logic.

"It", in "it defaults to", can only refer to the argument FRAME. The value of
FRAME remains nil in that case. 

The _default behavior_ of the function, that is, the behavior when FRAME is nil,
is to use the selected frame. But "it" - the value of parameter FRAME does not
default to anything. There is no parameter defaulting involved here.

What needs to be said is simply that a nil value of FRAME means that the
selected frame is used.