From: "Wolfgang Nádasi-Donner" <wonado@...>
Date: 2007-01-27T20:40:05+09:00
Subject: Re: pass by reference?

>>>>> Code >>>>>

def modifying(a_param)
   a_param = "hi"
end

def modifying2(a_param=a_value)
   a_param = "hi"
end

def modifying3(a_param)
   a_param[0..-1]= "hi"
end

a_value = "low"
modifying a_value
case a_value
when "hi"
   puts "Passed by reference"
when "low"
  puts "Passed by value"
else
  puts "Passed away"
end

a_value = "low"
modifying2 a_value
case a_value
when "hi"
   puts "Passed by reference"
when "low"
  puts "Passed by value"
else
  puts "Passed away"
end

a_value = "low"
modifying3 a_value
case a_value
when "hi"
   puts "Passed by reference"
when "low"
  puts "Passed by value"
else
  puts "Passed away"
end

>>>>> Output >>>>>

Passed by value
Passed by value
Passed by reference

>>>>> EoE >>>>>

I would name it somehow "call by assignment of value to local variable", because
the value of the actual parameter is assigned to the local variable used as a
formal parameter.

except for "Fixnum" etc. this is a pointer to an object. If one changes the
object itself, it will work like  "by reference", otherwise only the local
variable is affected, without having any effect to the outside world.

Wolfgang N�dasi-Donner