From: "Ara.T.Howard" <Ara.T.Howard@...>
Date: 2005-09-10T01:22:24+09:00
Subject: Re: quick print type debugging

On Sat, 10 Sep 2005, Eric Mahurin wrote:

> Anybody think something like this would be useful?
>
> module Kernel
>  def d(message="",&block)
>    ret = block.call
>    $stderr.puts("DEBUG: #{block.inspect} #{message} =>
> #{ret}") if $DEBUG
>    ret
>  end
> end

yeah - but maybe ENV['DEBUG'] vs $DEBUG so one could just

   DEBUG=1 ruby a.rb

$DEBUG makes many packages VERY noisy when loaded...

>
>
> irb(main):020:0> $DEBUG=true
> => true
> irb(main):019:0> d{1+2*3}
> DEBUG: #<Proc:0xb7df9adc@(irb):19>  => 7
> => 7
> irb(main):020:0> $DEBUG=false
> => false
> irb(main):021:0> d{1+2*3}
> => 7
>
> If you have an expression to want to see the result of, you
> just surround it with d{...}.  The block.inspect gives you the
> filename and line number and you get the evaluated value.  No
> need to have a separate "p" or "puts" statement (and possibly
> assignment to a variable) because this returns the value.
>
> What would be nice is if you could somehow convert the block
> back to text (and put it in the debug message).  Anybody know
> how to do that?  I know I could make the block be a string of
> the code instead to solve the problem (d{"..."}), but that
> would be uglier and less efficient when we have debugging off
> (because we have to eval).
>
>
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>

-a
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