Ruby on Rails: what does "equals" symbol mean as a parameter?

Some open source I've been using has the below line as a function declaration:

def parse_query(query=nil, options={}, models=nil)

What effect do the "equals" symbols have on the statement? Does it just make the parameters optional?

What does |= mean in ruby?

Ruby has an or-equals operator that allows a value to be assigned to a variable if and only if that variable evaluates to either nil or false .

What is a parameter in ruby?

What is a parameter? Parameters in ruby are variables that are defined in method definition and which represent the ability of a method to accept arguments. So, if we will not have the appropriate parameters, then we will not be able to pass arguments to a method that will contain the data we need.

It sets the default value of the parameter, if the person calling the function does not specify one.