Kazuyoshi Tlacaelel wrote: > > I got it, I go it, I got it!!!!!!!! > > > def change str > str.replace '...' > end > > str = '.' > change str > puts str > > #=> ... > > # yey!
(Hey guys, I realize this thread is a month old, but its relevant to something I'm doing right now.) Wow, this is the first time I've been disappointed by Ruby. This seems to me to be a _very_ poor choice. This (real code)... string = 'a string' copy = string string.replace 'a different string' ...seems a very poor substitute for this (pseudocode), which I would expect to have the same result... string = 'a string' copy = *string string = 'a different string' ...because the real code requires the changer of the string to know that there is going to be a copy made of the string. Here's a more realistic example (assume Person is a class that allows new instance variables to be created at runtime; in fact, I have completely implemented such a Person class and the irb I/O shown is completely real): irb> p = Person.new => #<Person:0x2bc43d0 @field_list=[:first_name, :last_name, :middle_name, :location, :primary_email, :primary_phone_number]> irb> p.personal_email = '[EMAIL PROTECTED]' => "[EMAIL PROTECTED]" irb> p => #<Person:0x2bc43d0 @personal_email="[EMAIL PROTECTED]", @field_list=[:first_name, :last_name, :middle_name, :location, :primary_email, :primary_phone_number, :personal_email]> irb> p.primary_email = p.personal_email => "[EMAIL PROTECTED]" irb> p => #<Person:0x2bc43d0 @personal_email="[EMAIL PROTECTED]", @primary_email="[EMAIL PROTECTED]", @field_list=[:first_name, :last_name, :middle_name, :location, :primary_email, :primary_phone_number, :personal_email]> irb> p.personal_email.replace '[EMAIL PROTECTED]' => "[EMAIL PROTECTED]" irb> p => #<Person:0x2bc43d0 @personal_email="[EMAIL PROTECTED]", @primary_email="[EMAIL PROTECTED]", @field_list=[:first_name, :last_name, :middle_name, :location, :primary_email, :primary_phone_number, :personal_email]> Is there really no way to do this such that the line "p.personal_email.replace '[EMAIL PROTECTED]'" can be replaced with "p.personal_email = '[EMAIL PROTECTED]'" and both strings will be modified? I think that's terrible--obviously, it's pretty realistic to expect that code like this would occur, but making it possible it requires every piece of code that changes p.personal_email to know that there is or could be a copy of it made. It makes String.= virtually useless, because in order to make it possible for a user to create a new String that always reflects the contents of another String, one must always use String.replace instead of String.= to assign values to Strings. It seems like the best solution would simply be to add an =* operator (to Object itself, ideally) such that this would be possible, in place of the line "p.primary_email = p.personal_email" above: p.primary_email =* p.personal_email #p.primary_email now contains a pointer directly to p.personal_email instead of containing a pointer to the same object that p.personal_email points to Of course, that is easier said than done, but I can't think of any other solution that comes close to being as elegant. Am I missing something? Is there already a way to create pointers to pointers in Ruby so that this problem can be avoided? Thanks, Doug -- Posted via http://www.ruby-forum.com/. --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en -~----------~----~----~----~------~----~------~--~---
