Ruby Object#send vs. negated equal

Question

Why does "A".send('!='.to_sym, "B") raises a NoMethodError in Ruby 1.8.7 while "A" != "B"does not - and how would the correct syntax for Object.send look like?

score 5 · Accepted Answer · answered Mar 08 '12 at 13:08

5

!= isn't a method in ruby 1.8 It's hardwired to be the negation of calling ==

answered Mar 08 '12 at 13:08

Frederick Cheung

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Any idea where != is defined in 1.9? I can't find it neither in Object nor in String... – user1196609 Mar 08 '12 at 13:22
@user1196609 You probably missed it because it was written in C, not Ruby. It's in [object.c](https://github.com/ruby/ruby/blob/6d6b4569fc153149ce648268e4d1df00f7dfa1bc/object.c#L151-156) and defined via `rb_define_method(rb_cBasicObject, "!=", rb_obj_not_equal, 1);` – brymck Mar 08 '12 at 14:04
@Bryan: This depends entirely on the Ruby implementation. In [Rubinius](http://Rubini.us/), it's written in Ruby and lives in [kernel/bootstrap/basicobject.rb](https://GitHub.Com/Rubinius/Rubinius/blob/master/kernel/bootstrap/basicobject.rb#L20-22) and looks like this: `def !=(other) self == other ? false : true end`. – Jörg W Mittag Mar 09 '12 at 01:02

score 3 · Answer 2 · answered Mar 09 '12 at 00:47

3

Since the second half of the question hasn't been answered yet:

'A'.send(:==, 'B').send(:!) # Ruby 1.9

!'A'.send(:==, 'B')         # Ruby 1.8

answered Mar 09 '12 at 00:47

Jörg W Mittag

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Ruby Object#send vs. negated equal

2 Answers2