A fixed size LIFO data structure, optionally free of duplicates. They feel a lot like arrays, but differ in some important areas like indexing. This is e.g. useful for keeping a history of recent actions.

Create a new Revolver:

r = Revolver.new(3)
#=> #<Revolver: []>

Create a Revolver with unique elements:

r = Revolver.new(3, true)
#=> #<Revolver: []>

Alternatively, you can create a Revolver from an existing array:

Revolver.from_array([*1..3])
#=> #<Revolver: [1, 2, 3]>

Or from a list of elements:

Revolver[*1..3]
#=> #<Revolver: [1, 2, 3]>

You can also create a unique Revolver that way:

Revolver.from_array([1, 1, 3], true)
#=> #<Revolver: [1, 3]>

Add elements:

r = Revolver.new(3).push(1).push(2).push(3)
#=> #<Revolver: [1, 2, 3]>
r.push(4)
#=> #<Revolver: [2, 3, 4]>
r << 5 << 6
#=> #<Revolver: [4, 5, 6]>

Remove an element from the end:

r.pop
#=> 6

Check a Revolver's size:

r.size
#=> 2

A Revolver can be indexed like an array:

r = Revolver.from_array([*1..5])
#=> #<Revolver: [1, 2, 3, 4, 5]>
r[4]
#=> 5

However, indices wrap around:

r[10]
#=> 1

This also works for negative indices:

r[-1]
#=> 5
r[-6]
#=> 1
r[-8]
#=> 3

Finally you can get a plain array out of a Revolver:

r.to_a
#=> [1, 2, 3, 4, 5]

• Wojtek Mach for adding Revolver.[].

Copyright (c) 2012 Michael Kohl

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