From: David Alan Black <dblack@...>
Date: 2002-04-12T06:07:44+09:00
Subject: Re: How to Make a Method Ineffective Efficiently?

Hello --

On Fri, 12 Apr 2002, William Djaja Tjokroaminata wrote:

> Hi,
>
> I am having a problem regarding coding efficiency (both for the execution
> time and for the typing itself).  Basically, I have a method that may or
> may not print depending on a flag, such as
>
>     ....
>     def print_info (*text)
>       if @debugging
>         ....
>         @file.write (text.join)
>       end
>     end
>
> Originally, I have put the flag in the calling class itself, but it made
> me typing the flag in too many places:
>
>     ....
>     print_info ("#{obj1} #{obj2} .... #{obj1000}") if @debugging #format A
>
> (because in reality the flag or condition may not be that
> short).  Therefore, just like in the first fragment of codes, I have put
> the flag in the print_info method itself, so that I can simply write
>
>     ....
>     print_info ("#{obj1} #{obj2} .... #{obj1000}") #format B
>
> and whether it actually prints or not is controlled by the flag in the
> print_info, which I can control without having to type in too many places.
>
> However, now I have a problem with execution efficiency.  With the last
> format (format B), whether or not I actually print, the methods to_s of
> obj1, ..., obj1000 are called.  The methods to_s themselves may be very
> complicated.  In the first format (format A), the methods to_s are not
> called at all if @debugging is equal to false.
>
> I don't want to type "if @debugging" everywhere (they clutter the codes),
> but I also want to have efficient execution, which in this case is
> equivalent to if @debugging is false, then the print_info method is
> ineffective, not even the passed arguments.  Is there any way I can
> accomplish what I want easily?
>
> (My current solution is to use format B, and try to minimize the argument
> overhead, by minimizing the number of arguments and doing processing
> inside the print_info method below the "if @debugging" line as much as
> possible.)

I haven't even tried to run this, let alone test it.... but could you
put the stuff in a block instead of an argument list?  Something like:

   def print_info
     if @debugging
        @file.write(yield)
     end
   end

   # ...

   print_info { "#{obj1} #{obj2}" }


David

-- 
David Alan Black
home: dblack@candle.superlink.net
work: blackdav@shu.edu
Web:  http://pirate.shu.edu/~blackdav