Question

Is there a convention for the use of => or : in Ruby 1.9+? like:

:param => "foo"

or

param: "foo"

EDIT: Thanks for the feedback, I edited the question to make it more clear.

Answer 1

There is a difference; The newer “JSON” style of hash creation can only be used with symbol keys. Demonstrated below.

{ param: "foo" }

is equivalent to

{ :param => "foo" }

So you cannot use it to create this hash:

{ "foo" => "bar" }

Or this one:

{ 0 => "One" }

This makes a lot of sense, since it is best practice to use symbol keys when you can.

Edit:
Also in your example, { param => "foo" } the value of the variable param will be used as the key.

so

param = :foo
{ param => "bar" }

is equivalent to

{ :foo => "bar" }