Learning Rails

Variables, Methods, and Attributes

TestbedController is a pretty dull class so far. If you start Rails (with ruby script/server, the >> button in Heroku, or whatever does it in the environment you’ve installed), and visit http://localhost:3000/testbed/, you’ll get a mostly blank response. There’s nothing in @result, because TestbedController’s index method doesn’t actually do anything.

That’s easily fixed. Change the definition of index to:

def index
   @result = 'hello'
end

Now, when you load the page, you’ll see “hello” as the result. (This is not exciting enough to deserve a screenshot.)

Variables

@result is a variable, a container for information. Because the name of the variable started with @, it is an instance variable, connected to the object in such a way that other objects can see it. That let the view retrieve it to shows its value. The new line of code assigned (=) an expression to the @result variable, the string hello.

The string was surrounded with single quotes (') to indicate that it was a string, a series of characters, rather than another variable name or something else entirely. If you need to include an apostrophe or single quote inside of a single-quoted string, just put a backslash (\) in front of the quote, as in 'Hello! Ain\'t it a pretty day?'. This is called escaping the quote, hiding it from normal processing.

Note

Ruby also lets you surround strings with double quotes. Double-quoted strings offer a lot more escaping functionality, but single-quoted strings are ...