From: Robert Klemme <shortcutter@...>
Date: 2007-04-04T01:10:04+09:00
Subject: Re: Weird behaviour of set_trace_func in 1.8.5

On 03.04.2007 17:38, Tomasz Wegrzanowski wrote:
> Hello, I found that set_trace_func is behaving in a weird way,
> missing some call events.

That's probably because the call was never done.  You probably ran into 
the difference between

ruby -e 'def foo(a,b) end; set_trace_func lambda {|*a| p a}; foo 1'

and

ruby -e 'def foo() raise ArgumentError end; set_trace_func lambda {|*a| 
p a}; foo 1'

In the first case the interpreter detects the argument error but in the 
second case the method does it by itself.  Typically you will see 
something like

def foo(*a)
   raise ArgumentError unless a.size > 3
   # ...
end

> Calls with bad number of arguments to other functions like Array#[]
> work correctly.

That may be because Array#[] accepts different numbers of arguments and 
does the argument processing by itself.

I am not sure what you are actually trying to achieve.  Can you elaborate?

Regards

	robert