From: Rich Kilmer <rich@...>
Date: 2002-08-24T22:37:18+09:00
Subject: RE: equivalent of python's __debug__



> -----Original Message-----
> From: David Garamond [mailto:davegaramond@icqmail.com]
> Sent: Saturday, August 24, 2002 8:47 AM
> To: ruby-talk ML
> Subject: Re: equivalent of python's __debug__
> 
> ts wrote:
> >>>>>>"D" == David Garamond <davegaramond@icqmail.com> writes:
> >>>>>
> >
> > D> def foo(self, x, y):
> > D>      if __debug__:
> > D>          self.__doc__x = "...some longish string..."
> > D>          self.__doc__y = "...some also longish string..."
> > D>          self.__doc_spec1__ = "...yet another string..."
> > D>          ...
> > D>      ...
> >
> >  Well, I've perhaps not understood but you can write (like
previously
> said)
> >
> > pigeon% ruby -e 'if $DEBUG; a = "a long string"; p a; end'
> > pigeon%
> >
> > pigeon% ruby -de 'if $DEBUG; a = "a long string"; p a; end'
> > "a long string"
> > pigeon%
> 
> but "a long string" still gets allocated by ruby. i want optimize
_away_
> the debug portion, so ruby doesn't consider it exist at all.
> 

Well, Ruby does parse and place those (long string) elements within the
Abstract Syntax Tree of the interpreter, but they are not allocated
during every call through a method, so the impact is lower.  Remember
that Ruby is interpreted so this minimization makes a difference.
Another idiom I often use is:

def foo
  $DEBUG && (puts "entered foo")
  ...other stuff...
end

Because it's a logical && if $DEBUG is negative the right hand statement
will not be evaluated.