Equivalent of “pass” in Ruby

Question

In python there is a pass keyword for defining an empty function, condition, loop, ... Is there something similar for Ruby?

Python Example:

def some_function():     # do nothing     pass 

Answer 1

No, there is no such thing in Ruby. If you want an empty block, method, module, class etc., just write an empty block:

def some_method end 

That's it.

In Python, every block is required to contain at least one statement, that's why you need a "fake" no-op statement. Ruby doesn't have statements, it only has expressions, and it is perfectly legal for a block to contain zero expressions.

Answer 2

nil is probably the equivalent of it:

def some_function     nil end 

It's basically helpful when ignoring exceptions using a simple one-line statement:

Process.kill('CONT', pid) rescue nil 

Instead of using a block:

begin     Process.kill('CONT') rescue end 

And dropping nil would cause syntax error:

> throw :x rescue SyntaxError: (irb):19: syntax error, unexpected end-of-input         from /usr/bin/irb:11:in `<main>' 

Notes:

def some_function; end; some_function returns nil.

def a; :b; begin; throw :x; rescue; end; end; a; also returns nil.