Feature #7998
closed
"def" should return a value (the symbol of the method name) instead of nil
Added by pmarreck (Peter Marreck) over 11 years ago.
Updated about 10 years ago.
Description
The C code that implements Ruby method definitions already creates a symbol corresponding to the method name.
I propose that the "def... end" block returns this symbol.
This would allow the following elegant Ruby code:
protected def foo(); end
private def bar(); end
since "protected" and "private" already take symbol arguments.
I estimate that this would be extremely easy to implement while creating extremely minimal existing code impact.
I proposed this idea to the #ruby IRC channel on freenode.net and it was received very well, they encouraged me to file this ticket! Thank you for considering.
+1
While the proposed usage is good, I immediately thought about this:
new_meth_name = module_eval <<-RUBY
def prefix_#{val}_postfix
...
end
RUBY
=begin
It has been suggested long long ago. Probably more than once. Here is a link to one: #3753.
Once we start looking at code like that for a while will we then start to think, why not just:
public foo()
...
end
protected foo()
...
end
private bar()
...
end
=end
This is a nice addition indeed and I remember I asked for it too in the
past. One usage could be method annotation like what is done in some
command line library:
desc 'Do something'
def do_something
...
end
The above code looks nice but I believe its underlying code involves
using method_added and is fragile when method_added is also used for
other functionalities.
If def returns method name, then a comma is all we need to remove the
meta-programming complexity.
desc 'Do something',
def do_something
...
end
I really wish one day this will be added to Ruby.
=begin
I have a problem with this feature.
module Frog
private def self.sound
"Ribbit!"
end
end
With this feature, def..end would return :sound, then private :sound would set Frog#sound to private. This is wrong. I defined Frog::sound, not Frog#sound. Surprise! There is no way for private :sound to know that I defined a metamethod, not an instance method; because def..end only returned a Symbol, not the whole definition. With this feature, "private def" only works for instance methods, not for metamethods.
=end
- Status changed from Open to Closed
def method return symbol on Ruby 2.1 or later.
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