From: Julian Tarkhanov <listbox@...>
Date: 2007-01-28T18:38:14+09:00
Subject: Re: pass by reference?


On Jan 27, 2007, at 12:27 AM, Andy Koch wrote:

> Is there a way to pass variables by reference into function.
>
> I have large string to pass and the pass by value seems to be  
> eating up too much memory.

Strings are mutable objects and should be treated as such :-)

def append_sour_word(strbuf)
   strbuf << " ...uck!"
end

text = "Good l"

append_sour_word(text) #=> "Good luck" is returned AND is contained  
in text now
text #=> "Good luck"

def assign_concatenated(strbuf)
   strbuf = strbuf + " ...uck!"
end

assign_concatenated(text) #=> "This is some new text" is returned but  
you lost the reference inside the function scope so the actual  
_value_ stays the same
text #=> still "Good luck", because you assigned another reference to  
your variable

def replace_content(strbuf)
   strbuf.replace(strbuf + " ...uck!")
end

replace_content(text) "Good l..uck!..uck!", but now with a desired  
side effect

text #=> "Good l..uck!..uck!", now you replaced the object with  
another one

Basically, to avoid confusion - if you eating up RAM avoid object  
_duplication_, because that's what eats it up. But it's perfectly  
possible to
massage objects in place without having to ask them for their "actual  
value".

-- 
Julian 'Julik' Tarkhanov
please send all personal mail to
me at julik.nl