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why does `variable-at-point' return 0?
From: |
Drew Adams |
Subject: |
why does `variable-at-point' return 0? |
Date: |
Fri, 6 Apr 2012 17:23:07 -0700 |
Just curious. Why doesn't `variable-at-point' return nil if there is no
variable at point?
All I can think of is that for some reason someone wanted to test using
`symbolp' instead of testing using `not' (or `and'). But I cannot imagine why.
Checking how `variable-at-point' is actually used in the source code did not
enlighten me. Each use just checks whether the value is `symbolp' and goes on
from there. An actual value of zero is never used AFAICT, except to serve as a
non-symbol.
There is no special need to distinguish nil from any variable - in Emacs Lisp
you cannot give the symbol nil a symbol-value other than nil.
It is true that (boundp nil) is true, so `boundp' is not a test of variableness.
But I don't see why it wouldn't be just as easy to test whether the value is nil
instead of testing whether it is a symbol. What am I missing?
- why does `variable-at-point' return 0?,
Drew Adams <=