[asdf-devel] Re: :DBG

[Ken Tilton]

It might be a better idea to have a new debugging project where lispers can
share their best & brightest utilities. I have some beauts.

-hp


On Mon, Nov 18, 2013 at 4:08 AM, Pascal Costanza <pc at p-cos.net> wrote:

> It hasn't been a problem in the past, because people stuck to the rules,
> at least in publicly available libraries, which is why you didn't observe
> any problems. If people stop sticking to the rules, it will become a
> problem.
>
> Pascal
>
> Sent from my iPad
>
> On 18 Nov 2013, at 10:00, Ken Tilton <kentilton at gmail.com> wrote:
>
> I for one have never understood the anal compulsiveness* of many Lispers
> over package sanctity.
>
> * Does it solve a problem, or is it just aneatness obsession?
>
> Dis donc, francois, how did you handle source that might be a good-sized
> little sexpr?
>
> -- His Professionalness
>
>
>
> On Mon, Nov 18, 2013 at 3:44 AM, Alessio Stalla <alessiostalla at gmail.com>wrote:
>
>> Well, Faré is obviously well aware of that, and has given an explanation
>> for why he is willing to "break the rules" this particular time. So "don't
>> dare touch the keywords package!" does not seem the right answer to me...
>> Faré, I understand your points, what fails me is: if this is a debug
>> macro nobody won't ever use in production code, why make it available in a
>> library at all? Why couldn't it simply live in your rc file? Or, you could
>> include it in uiop with a non-keyword name, and only bind it to :dbg in
>> your own environment. I fail to understand why you'd want to it be
>> available everywhere, everytime... and for everyone as well!
>>
>> Alessio
>>
>>
>> On Mon, Nov 18, 2013 at 9:28 AM, Pascal Costanza <pc at p-cos.net> wrote:
>>
>>> Hm, just when I thought this the mailing list for professional Common
>>> Lisp users.
>>>
>>> Off the top of my hat:
>>> http://www.lispworks.com/documentation/HyperSpec/Body/11_abcb.htm
>>>
>>>  Pascal
>>>
>>> Sent from my iPad
>>>
>>> On 18 Nov 2013, at 08:51, Hans Hübner <hans.huebner at gmail.com> wrote:
>>>
>>> Pascal,
>>>
>>> if you mean what you write, can you give some reasoning?
>>>
>>> -Hans
>>>
>>>
>>> 2013/11/18 Pascal Costanza <pc at p-cos.net>
>>>
>>>> DON'T TOUCH THE KEYWORDS PACKAGE! Are you crazy?!?
>>>>
>>>> This will be setting a very bad precedence. Just don't. Really!
>>>>
>>>> Pascal
>>>>
>>>> Sent from my iPad
>>>>
>>>> > On 18 Nov 2013, at 06:17, Faré <fahree at gmail.com> wrote:
>>>> >
>>>> > In ASDF 3.1.0.14, I introduced a macro :DBG (in uiop/utility.lisp).
>>>> > Yes, it's in the keyword package. Why?
>>>> > Because it's the one and only macro I want to be accessible from
>>>> everywhere
>>>> > without a prefix, yet without modifying existing defpackage forms to
>>>> make
>>>> > it accessible — because it's only used temporarily for debugging.
>>>> >
>>>> > :DBG is a macro for print-debugging. The syntax is
>>>> >   (:DBG tag forms... last-form)
>>>> > The semantics is that if tag is true, print the tag, then for each
>>>> > form, write its source and its values; return the values of the last
>>>> > form. If tag is false, just evaluate the last form and return its
>>>> > values. (Tag is typically a constant keyword or string, identifying
>>>> > the point where values are printed.)
>>>> > The expansion is rather space and time efficient, as far as the
>>>> > semantics permit.
>>>> >
>>>> > I find :DBG soooo useful for print-debugging. I've seen tens of
>>>> > variants of it, but every time with something not quite right in the
>>>> > syntax, semantics or implementation. I just wanted one variant that
>>>> > got everything right, and make it ubiquitous. Because when you need
>>>> > it, you need it now, and there's no time to modify things to load an
>>>> > additional library. And when you're done, you want minimal cleanup,
>>>> > too: just delete the form, except maybe keep the last subform.
>>>> >
>>>> > Previously, I was using (uiop:uiop-debug) from uiop/utility which
>>>> > allows you to load a magic file of your choice that defines a debug
>>>> > mode. The default one I provided was mine, which define :DBG as DBG in
>>>> > your current package (thereby avoiding symbol import issues). But that
>>>> > still adds a new definition everytime and an extra line or form to
>>>> > cleanup.
>>>> >
>>>> > I was recently convinced that using the keyword package instead makes
>>>> > perfect sense: on the one hand, that's using a shared namespace that
>>>> > it is polite to not pollute, but on the other hand, such a temporary
>>>> > print-debugging macro the only use case I imagine of otherwise wanting
>>>> > something to be immediately accessible without package prefixing yet
>>>> > without modifying the package definition form.
>>>> >
>>>> > It's still time to remove that macro before the next release, but I
>>>> > believe it's the right thing to include it, and maybe some of you will
>>>> > agree with me and start using it, if not from the yet unrelease ASDF
>>>> > 3.1.1, perhaps from a copy in your .sbclrc.
>>>> >
>>>> > —♯ƒ • François-René ÐVB Rideau •Reflection&Cybernethics•
>>>> http://fare.tunes.org
>>>> > The common argument that crime is caused by poverty
>>>> > is a kind of slander on the poor.
>>>> >        — H. L. Mencken
>>>> >
>>>>
>>>>
>>>
>>
>>
>> --
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>>
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>>
>
>
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