From: Stefan Rusterholz <apeiros@...>
Date: 2007-10-19T23:44:44+09:00
Subject: Re: the level of Ruby programmers vs PHP's

Ben Giddings wrote:
> On Oct 19, 2007, at 04:32, SpringFlowers AutumnMoon wrote:
>> print_debug(2**3)
>> print_debug(8**(1.0/3))
>> print_debug(a + 2.038)
>>   [...]
>>
>> it will print out the expression as well as the value at the same  
>> time,
>> as a convenience for testing and for debugging.
> 
> This is one of the few reasons I wish Ruby had macros.  Having a
> macro like this can be very useful, but it isn't possible with a
> function/method because the argument gets evaluated before being
> passed to the context of the function/method.  In the above examples
> print_debug would be passed 3, 8, 2.0 and some float value.
> 
> I don't know if it would be possible to have some special macroish
> functionality in Ruby that would allow "print_debug()" but not open
> the can of worms that is macros.
> 
> Ben


Ugly solution:
def debug_eval(code, binding)
  puts "#{code}\n=> #{eval(code, binding)}"
end

a = 3
b = 5
debug_eval(%{a*b}, binding)

Though IMHO all you need when you print the debug output of some 
statement is a label, such as
p [:value_of_foo, foo_expression]
That's usually sufficient here. I mean, when you use such a statement 
you *know* what expression you're inspecting. At least I seriously hope 
that such statements are only used for short time inspection and for 
that timeframe, your memory should be sufficient, no?

Regards
Stefan
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