Understanding Ruby's def keyword

TL;DR Under certain circumstances, dynamically defined symbols may break keyword arguments in Ruby 2.2. This was fixed in Ruby 2.2.3 and 2.3.

Specifically, when …

• there is a method with several keyword arguments and a double-splat a...

When a method has keyword arguments, Ruby offers implicit conversion of a Hash argument into keyword arguments. This conversion is perfo...

Ruby 3.0 introduced a breaking change in how it treats keyword arguments.

There is an excellent blog post on the official Ruby blog going ...

Writing ruby methods that accept both optional and keyword arguments is dangerous and should be avoided. This confusing behavior will be deprecated in Ruby 2.7 and removed in Ruby 3, but right now you need to know about the following caveats.

Con...

Access the Method object

Dead simple: Get the method object and ask for its owner:

"foo".method(:upcase)
# =>  #<Method: String#upcase> 

"foo".method(:upcase).owner
# => String

Look up a method's source location

Ruby 1.9 adds...

In the discussion of the difference between include and extend in Ruby, there is a misconception that extend would add methods to the singleton class of a ruby object as stated in many posts on this topic. But in fact, it is added to the a...

Starting with Ruby 2.0 you can define methods with keyword arguments.

In 2.1+ required keyword arguments can be defined by using a colon without default value:

Do you remember finding where a method is defined?

I recently learned from a senior colleague that Method objects ar...

Ruby has a set of methods to convert an object to another representation. Most of them come in explicit and implicit flavor.

"Keyword arguments" allow naming method arguments (optionally setting a default value). By using the double-splat operator, you can collect additional options. Default values for standard arguments still work (see adjective).

def greet(...