# RCR debug

**URL:** <https://www.ruby-forum.com/t/rcr-debug/91928>\
**Category:** Ruby\
**Created:** [April 13, 2007, 3:27pm UTC](https://www.ruby-forum.com/t/rcr-debug/91928 "2007-04-13T15:27:34Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![flatekmonkey](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/f/e8c25b/32.png) [@flatekmonkey](https://www.ruby-forum.com/u/flatekmonkey)\
**Post date:** [April 13, 2007, 3:27pm UTC](https://www.ruby-forum.com/t/rcr-debug/91928/1 "2007-04-13T15:27:34Z")

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Hi list

this is incredibly simple, but I just wanted to know what you think  
about it.

I really often write the following code

puts if $DEBUG

I guess you all do that to some extent, James just talked a newbie  
into it recently 😉

The first programmer’s virtue of course makes me do some things like  
def debug \*args, &blk  
return unless $DEBUG  
\<do something incredibly smart with the args ;)\>  
end  
and sometimes on some of my machines I will do something like

require ‘ilmig/tools/debug’

I feel that this might be so common place that a Kernel::debug or  
whatever other suitable name might be a good idea.

I am listening … 😉

Cheers  
Robert

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**Author:** ![flatekmonkey](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/f/e8c25b/32.png) [@flatekmonkey](https://www.ruby-forum.com/u/flatekmonkey)\
**Post date:** [April 13, 2007, 5:31pm UTC](https://www.ruby-forum.com/t/rcr-debug/91928/2 "2007-04-13T17:31:46Z")

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On 4/13/07, Robert D. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote:

> whatever other suitable name might be a good idea.
> 
> I am listening … 😉

For medium to large programs having a global $DEBUG flag is going to  
create lots of “line noise” as all those debug messages go whipping  
by.

I much prefer the fine grained control that the ‘logging’ and ‘log4r’  
packages give you.

require ‘logging’

class A  
def initialize  
@log = Logging::Logger[self]  
@log.debug “new object created ‘#{self.object\_id}’”  
end  
end

class B  
def initialize  
@log = Logging::Logger[self]  
@log.debug “new object created ‘#{self.object\_id}’”  
end  
end

Logging::Logger[‘A’].level = :warn  
Logging::Logger[‘B’].level = :debug

It’s a little more setup, but you have far greater control over what  
gets logged and what doesn’t. The framework also takes care of  
timestamps, outputting class info, etc.

And if you don’t want all that complexity, there is always the core  
Logger class that comes with Ruby.

Blessings,  
TwP

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**Author:** ![flatekmonkey](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/f/e8c25b/32.png) [@flatekmonkey](https://www.ruby-forum.com/u/flatekmonkey)\
**Post date:** [April 13, 2007, 10:01pm UTC](https://www.ruby-forum.com/t/rcr-debug/91928/3 "2007-04-13T22:01:17Z")

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On 4/13/07, Tim P. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote:

> > into it recently 😉  
> > I feel that this might be so common place that a Kernel::debug or  
> > whatever other suitable name might be a good idea.
> > 
> > I am listening … 😉
> 
> For medium to large programs having a global $DEBUG flag is going to  
> create lots of “line noise” as all those debug messages go whipping  
> by.  
> Tim the $DEBUG mechanism is quite primitive and other things are  
> needed for large scale development, no doubt.  
> My idea of the CR is orbiting around $DEBUG which is widely used in  
> quick hacks or small to medium scale development, but…  
> @log.debug “new object created ‘#{self.object\_id}’”  
> Logging::Logger[‘A’].level = :warn  
> Blessings,  
> TwP  
> … I take one idea from your mail, with your kind permission 😉

## Why not enhancing the semantics of $DEBUG at the same moment, I will elaborate

def Kernel.debug \*args, &blk  
return unless $DEBUG  
begin  
$DEBUG.puts args.join(" ") unless args.empty?  
blk.call $DEBUG if blk  
rescue  
warn $DEBUG does not respond to the #puts message  
end  
end

now you can write code like

debug “OMG this should be deadcode, why I am here, I just kept that  
code for sentimental reasons!!!”

or  
debug do  
puts “whatever”  
end

or

debug {  
| stream |  
stream.puts “@inst = #{@inst}”  
}

or  
debug do  
$DEBUG.print “one”  
end

## of course the -d switch of ruby would just set $DEBUG to $stdout, maybe a -l switch could be introduced to set $DEBUG to a writeable IO object representing

Now I realize I did not think about other debugging mechanisms, the  
core idea is just to simplify what I think is a common and useful  
idiom namely  
puts “/…” if $DEBUG

I do not think that this will compete with more advanced debugging,  
logging features, but why not enhance the $DEBUG switch as suggested  
above.

Yeah and before I forget, thx for your input Tim.

Cheers  
Robert

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**Author:** ![flatekmonkey](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/f/e8c25b/32.png) [@flatekmonkey](https://www.ruby-forum.com/u/flatekmonkey)\
**Post date:** [April 14, 2007, 4:29pm UTC](https://www.ruby-forum.com/t/rcr-debug/91928/4 "2007-04-14T16:29:32Z")

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On 4/13/07, Robert D. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote:

> Tim the $DEBUG mechanism is quite primitive and other things are  
> needed for large scale development, no doubt.  
> My idea of the CR is orbiting around $DEBUG which is widely used in  
> quick hacks or small to medium scale development, but…

A simple debug method seems like a great idea. But what happens when  
it ends up in Kernel and everyone starts using it? Now you’ll get all  
the debug messages from your code and all the library code that you  
include. That’s why I don’t like the $DEBUG option.

I know you want to put it into Kernel so everyone can use. But that’s  
the whole problem – everyone will start using it! And then it  
becomes not so useful.

This is similar to making sure that your code runs -w clean (i.e.  
won’t throw out warnings). The rails core is very bad about this –  
lot’s of warnings. Now you cannot find the warnings in your own code  
because all the rails warnings are cluttering things up.

Same problem with a global $DEBUG flag.

Just my $0.02 on the matter.

Blessings,  
TwP

PS Why not include this in the facets library? I think this would be  
a much more suitable place for such a creature.

[http://facets.rubyforge.org/](http://facets.rubyforge.org/)

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**Author:** ![flatekmonkey](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/f/e8c25b/32.png) [@flatekmonkey](https://www.ruby-forum.com/u/flatekmonkey)\
**Post date:** [April 14, 2007, 6:18pm UTC](https://www.ruby-forum.com/t/rcr-debug/91928/5 "2007-04-14T18:18:40Z")

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On Sat, 14 Apr 2007, Tim P. wrote:

> Just my $0.02 on the matter.
> 
> Blessings,  
> TwP
> 
> PS Why not include this in the facets library? I think this would be  
> a much more suitable place for such a creature.
> 
> [http://facets.rubyforge.org/](http://facets.rubyforge.org/)

alternatively

logger = Logger.new STDERR  
logger.level = ENV[‘DEBUG\_ENV\_FOR\_MY\_CODE’] ? Logger::DEBUG :  
LOGGER::INFO

logger.debug{ ‘now you have a debug method that can be turned on/off  
from the environment’ }

it’s prety kiss…

-a

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**Author:** ![flatekmonkey](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/f/e8c25b/32.png) [@flatekmonkey](https://www.ruby-forum.com/u/flatekmonkey)\
**Post date:** [April 14, 2007, 7:41pm UTC](https://www.ruby-forum.com/t/rcr-debug/91928/6 "2007-04-14T19:41:45Z")

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On 4/14/07, removed\_email\_address@domain.invalid [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote:

> > the debug messages from your code and all the library code that you
> > 
> > [http://facets.rubyforge.org/](http://facets.rubyforge.org/)  
> > -a  
> > –  
> > be kind whenever possible… it is always possible.
> 
> - the dalai lama

Ara I guess you are right about the Kernel, a standard library  
module/class might be better, voici Logger.  
Funnily I think I really have not done enough research about Logger  
after Tim’s input, well maybe because Tim just explained that he  
prefered Logger and that was not on my mind.  
Sorry Tim if I was not thoughtful enough.  
I feel that I just wanted to facilitate a common pattern, I had not  
though a second about if that common pattern was worth being  
facilitated…  
… probably it is not.  
Thanks for your input, I guess I’ll call it an RCR ;).

This is a great ML, they think for you, someone to write a solution  
for this weeks Ruby Q. for me ? :)))

Cheers  
Robert