What does << - CONSTANT do?

Question

 return <<-HTML <li> <a href = "some-link">Link-Title</a> </li> HTML 

What is <<-HTML in the first line and HTML in the last line for?

Answer 1

This is heredoc.

http://en.wikipedia.org/wiki/Here_document#Ruby

Answer 2

This is a document. Basically, this is a multi-line string literal.

In the lines after the line with <<-HTML these are literal lines concatenated by newline characters - until a final marker is reached, which in this case is equal to HTML .

Answer 3

To explicitly answer the question, this snippet returns a string:

<li>

 <a href = "some-link">Link-Title</a> 

</li>