What is <<- in ruby?

Question

From the Ruby_Newbie Guide to Symbols:

Author is trying to show a simplified implementation of the attr_writer method.

#!/usr/bin/env ruby

def make_me_a         


        

Answer 1

It's a heredoc. From the "Here Documents" documentation:

If you are writing a large block of text you may use a “here document” or “heredoc”:

expected_result = <<HEREDOC
This would contain specially formatted text.

That might span many lines
HEREDOC

The heredoc starts on the line following <<HEREDOC and ends with the next line that starts with HEREDOC. The result includes the ending newline.

Answer 2

It's a multi line string. The code evaluates code embedded inside string. More on multi line strings:

http://blog.jayfields.com/2006/12/ruby-multiline-strings-here-doc-or.html

P.S. Using eval is not recommended, alternatives - yield, instance_eval, class_eval.