From: danieldasilvaferreira@...
Date: 2018-01-09T18:57:11+00:00
Subject: [ruby-core:84786] [Ruby trunk Feature#14336] Create new method String#symbol? and deprecate Symbol class

Issue #14336 has been updated by dsferreira (Daniel Ferreira).


Looking at Smalltalk deeper we have: [Smalltalk Symbol class](https://www.gnu.org/software/smalltalk/manual-base/html_node/Symbol.html)

Symbol is a subclass of String. (If this was the reality in ruby I believe most of our problems would be resolved. Can we add it as possible solution?)

Also there is nothing stating that symbols are for identifiers. What we see is:

���
In general, you can use strings for almost all your tasks. If you ever get into a performance-critical function which looks up strings, you can switch to Symbol. It takes longer to create a Symbol, and the memory for a Symbol is never freed (since the class has to keep tabs on it indefinitely to guarantee it continues to return the same object). You can use it, but use it with care.���

All of this makes more sense to me. Remembers me the old days of ruby 1.8. I guess this is what Koichi was referring to when he mentioned going back in time before ruby 1.9.



----------------------------------------
Feature #14336: Create new method String#symbol? and deprecate Symbol class
https://bugs.ruby-lang.org/issues/14336#change-69502

* Author: dsferreira (Daniel Ferreira)
* Status: Rejected
* Priority: Normal
* Assignee: 
* Target version: 
----------------------------------------
From  the discussions on the three previous issues related to the String vs Symbol subject ([5964](https://bugs.ruby-lang.org/issues/5964), [7792](https://bugs.ruby-lang.org/issues/7792), [14277](https://bugs.ruby-lang.org/issues/14277)) there are some conclusions we can assume:
* Current String vs Symbol is not the ideal scenario. See: Matz and Koichi comments.
* Current philosophy is to use Symbols as identifiers and Strings when strings are needed.
* Current situation is that Symbols are being used in many code bases as strings except for strings that really need the String methods.
* Current situation is that we are designing APIs to handle both String and Symbol inputs forcing an overhead of API development.

I propose the deprecation of `Symbol` class and the introduction of `String#symbol?`.

```ruby
foo = :foo
foo.class # => String
foo.symbol? # => true
bar = "bar"
bar.class # => String
bar.symbol? # => false
```

For backwards compatibility transition path I propose:

```ruby
class Symbol
  def self.===(var)
    warn ("Warning message regarding deprecated class")
    if var.class == Symbol
      true
    elsif var.class == String && var.symbol?
      true
    else
      false
    end
  end
end

class String
  def is_a?(klass)
    case klass
    when String
      true
    when Symbol
      self.symbol?
    else
      false
    end
  end
end
```



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