There are two types of comments in HAML files.
1. Single line Comment
Single line comments can be written in two ways.This will create the HTML comment that will sent to client(visible in 'view source' of the web page)
/ comment text
This will comment the code so that will not sent to the client:
-# comment text
2. Multi line Comment
-# Everything indented below the comment symbol is considered as comment below text is not visible in view source of the file