Eli Barzilay wrote:
> (And the point is that #; is an s-expr operation, and if I
> don't know where my sexprs end, then chances are my code is bad
> anyway.)
And since you also agree that #; comeents are mainly used during
debugging when you know or suspect your code is bad anyway, then
you've essentially conceded my point ...
> On Sep 29, Per Bothner wrote:
>>> [...]
>>> (+
>>> (- foo
>>> bar
>>> #|
>>> (this is
>>> a
>>> long
>>> (expression (that
>>> has
>>> many
>>> parens)))|#))
>> Aa I said above: you really don't want this in production code, or
>> more generally anything that is 'checked in" (to a source-code
>> repository).
>
> Huh??? Are you seriously suggesting that repositories should contain
> no commented code?
I assume you meant to write "commented-out code". And, yes, there is
little or no justification for commented-out code in repositories
*unless* it is accompanied by a non-s-expr comment explaining why
it is commented-out.
> Here's something that didn't come up in this thread, and that I use a
> lot: the nice thing about having line-, block-, and sexpr-level
> comments is that they can compose in useful ways. You said that you'd
> always want to add a comment about why the code is disabled, which I
> always do like this:
>
> #; ; this code is ...
> (...)
This works as long as the comment fits on a line. So now you have a
coding style that strongly encourages terse comments.
I guess you could do:
#; the code is commented out
;; because the function foo is broken
( .(foo ..).)
;; instead we have to sue to slower bar:
( (bar ...))
The problem is it is easier to lose track what is commented out (and
why) than with plain old-fashioned block comments, which are much more
visibly obvious where they begin and end.
> And because the whole comment openning is on one line, it can be
> `toggled' with a single semicolon:
>
> #; ; version A
> (...A...)
> ;#; ; version B
> (...B...)
> #; ; version C
> (...C...)
>
> (And yes, this is mostly useful for debugging.)
This argues for a conditional-compilation/reader mechanism, like
Common Lisps #+ and #-.
--
--Per Bothner
per_at_bothner.com http://per.bothner.com/
Received on Sat Sep 30 2006 - 13:23:02 UTC