From: Robert Dober <robert.dober@...>
Date: 2008-02-14T22:03:39+09:00
Subject: Re: [RRR] Robert's Ruby Riddle: Local or Method

On Wed, Feb 13, 2008 at 11:11 PM, James Gray <james@grayproductions.net> wrote:
> On Feb 13, 2008, at 9:38 AM, Robert Dober wrote:
>
>  > Hi list I was just thinking it might fun to present some of Ruby's
>  > features in form of a riddle.
>  > There was an interesting thread yesterday and as I always forget the
>  > basics I wrote some testcode to find out if the local or the method
>  > prevails, I made a stupid
>  > error and had to rewrite the code, or maybe did I not? This depends on
>  > the answer of the riddle.
>  > Todays Ruby Riddle is:
>  >
>  > Can the following code be used to test if the argument of puts is the
>  > local variable "a" or the method "a"? And if so please explain how.
>  >
>  > <code>
>  > a = 42
>  > def a; 42 end
>  > puts a
>  > </code>
>  > I leave some blank lines here so that people can reply without
>  > spoiling if for other readers.
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>  You can set a trace function for this:
>
>  $ ruby -e 'set_trace_func lambda { |event, _, _, name, _, _| puts
>  "method called" if event == "call" and name == :a }; eval(ARGF.read)'
>  riddle.rb
>  42
>  $ ruby -e 'set_trace_func lambda { |event, _, _, name, _, _| puts
>  "method called" if event == "call" and name == :a };
>  eval(ARGF.read.to_a[1..-1].join)' riddle.rb
>  method called
>  42
>
>  James Edward Gray II
>
>

I thought the debugger and the profiler were the only solutions, that
is quite one James!
R.

-- 
http://ruby-smalltalk.blogspot.com/

---
Whereof one cannot speak, thereof one must be silent.
Ludwig Wittgenstein