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However, one thing I have noticed is that Rubyists and Pythonistas bring different assumptions to the table. What is intuitive to one group seems ad hoc and downright weird to the other.

Here’s one example that I noticed.

In Python, the construct "x.y" means lookup the name "y" in the dictionary of "x". (Ok, that’s simplified, but you get the picture). The result of that lookup may be a value (instance data), or may be a function that can be called (member functions). In other words, "." is basically a lookup operation.

In Ruby, the construct "x.y" means send a message named "y" to the object represented by "x". All operations on an object must be done through the sending of a message.

This leads to all kinds of non-intuitive behavior if you are expecting the wrong thing. For example, one Pythonista commenting on the fact that "x.y" and "x.y()" are equivalent asks the question: "How do you get access to the y function inside x?".

A Rubyist’s response to the question is "Huh?". You see, there are no "functions" in Ruby. At least not in the way the question assumes. Ruby’s unit of execution is a method, and methods are not first class objects in Ruby. If you wish to have a callable object that references a method on a particular object, then that is easily accomplished by asking the object for a Method object.

  o = Object.new
  m = o.method(:to_s)
  m.class              # => Method

Note the difference between a method (an internal Ruby construct) and a Method object (an object that represents the internal method bound to an instance). To "call" a method object (or any callable object in Ruby), you send the object the "call" message. So, the result of calling m should be identical to the result of sending to_s to o directly. And we see that it is.

  m.call               # => "#<Object:0x401c8618>"
  o.to_s               # => "#<Object:0x401c8618>"

Although Python and Ruby are similar in many ways, their basis for computation is quite different in some fundamental ways. Python follows C++ and Java in using "." as a structure selector operation, while Ruby is more closely attuned to Smalltalk’s message sending paradigm. Both approaches work and are interally consistent, but be prepared for surprises if you try to interpret one using the assumptions of the other.