* Qs on free variable occurrences
@ 2006-05-01 21:25 Drew Adams
2006-05-01 21:29 ` Drew Adams
0 siblings, 1 reply; 5+ messages in thread
From: Drew Adams @ 2006-05-01 21:25 UTC (permalink / raw)
Consider variable `minibuffer-history-position', in library simple.el.
1. It is bound (`let') in function `repeat-complex-command'.
2. It is assigned a value at the top level of the file.
3. It is both used (evaluated) and assigned a value in functions
`previous-matching-history-element' and `next-history-element'.
4. Byte-compiling the file gives no warning of the variable being used as a
free variable (in #3 and #4).
This is not a criticism, but a couple of questions.
a. Why #4? Is it because the byte-compiler cannot detect these as free
occurrences of the variable or is it intentional (TRT)? If the latter,
what's the rationale?
b. Is this coding style considered good or bad? In particular, should
`minibuffer-history-position' be declared a global variable by giving it a
defvar?
Just trying to learn. Supporting reasons would help me understand. Thx.
^ permalink raw reply [flat|nested] 5+ messages in thread
* RE: Qs on free variable occurrences
2006-05-01 21:25 Qs on free variable occurrences Drew Adams
@ 2006-05-01 21:29 ` Drew Adams
2006-05-06 14:57 ` Drew Adams
0 siblings, 1 reply; 5+ messages in thread
From: Drew Adams @ 2006-05-01 21:29 UTC (permalink / raw)
Consider variable `minibuffer-history-position', in library simple.el.
1. It is bound (`let') in function `repeat-complex-command'.
2. It is assigned a value at the top level of the file.
3. It is both used (evaluated) and assigned a value in
functions `previous-matching-history-element' and
`next-history-element'.
4. Byte-compiling the file gives no warning of the variable
being used as a free variable (in #3 and #4).
This is not a criticism, but a couple of questions.
a. Why #4? Is it because the byte-compiler cannot detect these
as free occurrences of the variable or is it intentional (TRT)?
If the latter, what's the rationale?
b. Is this coding style considered good or bad? In particular,
should `minibuffer-history-position' be declared a global
variable by giving it a defvar?
Just trying to learn. Supporting reasons would help me understand.
I should have tried `C-h v' first. It says that this variable is defined in
C source code. That would perhaps explain #4. I still wonder about the
coding style. Consider my questions in a context where the variable was not
predefined in C. Thx.
^ permalink raw reply [flat|nested] 5+ messages in thread* RE: Qs on free variable occurrences
2006-05-01 21:29 ` Drew Adams
@ 2006-05-06 14:57 ` Drew Adams
2006-05-07 5:00 ` Richard Stallman
0 siblings, 1 reply; 5+ messages in thread
From: Drew Adams @ 2006-05-06 14:57 UTC (permalink / raw)
Resending, as I got no reply. Suppose this variable were not predefined in
C. Would the Lisp coding style used be appropriate in that case, or should
the variable be declared via `defvar'?
Consider variable `minibuffer-history-position', in library
simple.el.
1. It is bound (`let') in function `repeat-complex-command'.
2. It is assigned a value at the top level of the file.
3. It is both used (evaluated) and assigned a value in
functions `previous-matching-history-element' and
`next-history-element'.
4. Byte-compiling the file gives no warning of the variable
being used as a free variable (in #3 and #4).
This is not a criticism, but a couple of questions.
a. Why #4? Is it because the byte-compiler cannot detect these
as free occurrences of the variable or is it intentional
(TRT)? If the latter, what's the rationale?
b. Is this coding style considered good or bad? In particular,
should `minibuffer-history-position' be declared a global
variable by giving it a defvar?
Just trying to learn. Supporting reasons would help me understand.
`C-h v' says that this variable is defined in C source code. That
would perhaps explain #4. I still wonder about the coding style.
Consider my questions in a context where the variable was not
predefined in C. Thx.
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: Qs on free variable occurrences
2006-05-06 14:57 ` Drew Adams
@ 2006-05-07 5:00 ` Richard Stallman
2006-05-07 14:54 ` Drew Adams
0 siblings, 1 reply; 5+ messages in thread
From: Richard Stallman @ 2006-05-07 5:00 UTC (permalink / raw)
Cc: emacs-devel
4. Byte-compiling the file gives no warning of the variable
being used as a free variable (in #3 and #4).
This is not a criticism, but a couple of questions.
a. Why #4? Is it because the byte-compiler cannot detect these
as free occurrences of the variable or is it intentional
(TRT)? If the latter, what's the rationale?
It is because the variable has a definition elsewhere.
(In the C code.)
I will add a comment to say so.
b. Is this coding style considered good or bad? In particular,
should `minibuffer-history-position' be declared a global
variable by giving it a defvar?
If it weren't used in the C code, that's what we'd do.
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2006-05-07 14:54 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz follow: Atom feed
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2006-05-01 21:25 Qs on free variable occurrences Drew Adams
2006-05-01 21:29 ` Drew Adams
2006-05-06 14:57 ` Drew Adams
2006-05-07 5:00 ` Richard Stallman
2006-05-07 14:54 ` Drew Adams
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