Unique construct for passing a hash

Question

I have never seen this construct for building a hash. do_stuff(records: records) Does this only work in a parameter list being sent to a method? Is it documented an

Answer 1

The new syntax for Hashes in Ruby 1.9 allows you to drop the hash rocket.

#Pre 1.9
{:key => value}

#1.9+
{key: value}

Both of the above are equivalent.

One thing to keep in mind when using the new hash syntax is that the key will always be treated as a symbol.

Answer 2

There are two things going on here. The { key: value } syntax is new in Ruby 1.9. It is equivalent to { :key => value }.

Also, Ruby methods have some syntactical sugar that allows you to pass in a hash literal as the last argument of the method without including the curly braces. This is not new in Ruby 1.9. So

do_stuff(key: value)

Is equivalent to

do_stuff({ key: value })

Just to remind you, this only works if the hash is the last argument to the method.