# Indexable

Indexable it a module, like Enumerable, but provides methods specific
to an indexable collection. The Indexable module can be used independently,
but Facets can also automatically use it to extend Array.

    require 'facets/array/indexable'

## Indexable#head

    a = [1,2,3,4,5]
    a.head.assert = [1]

## Indexable#tail

    a = [1,2,3,4,5]
    a.tail.assert = [2,3,4,5]

## Indexable#foot

    a = [1,2,3,4,5]
    a.foot.assert = [5]

## Indexable#body

    a = [1,2,3,4,5]
    a.body.assert = [1,2,3,4]

## Indexable#mid

    a = [1,2,3,4,5]
    b = [1,2,3,4,5,6]
    a.mid.assert = 3
    b.mid.assert = 4
    a.mid(1).assert = 4
    b.mid(1).assert = 5
    b.mid(2).assert = 6
    b.mid(-1).assert = 3

## Indexable#middle

    a = [1,2,3,4,5]
    b = [1,2,3,4,5,6]
    a.middle.assert = [3]
    b.middle.assert = [3,4]

## Indexable#thru

    [0,1,2,3,4,5].thru(2,4).assert = [2,3,4]
    [0,1,2,3,4,5].thru(0,1).assert = [0,1]

## Indexable#first=

    a = [1,2]
    a.first = 0
    a.assert = [0,2]

## Indexable#last=

    a = [1,2]
    a.last = 3
    a.assert = [1,3]

## Indexable#ends

    [1,2,3,4,5].ends.assert = 4

## Indexable#pos

    a = [1,2,3,4,5]
    a.pos(1).assert = 0
    a.pos(-1).assert = 4

## Indexable#range

    a = [1,2,3,4,5]
    b = [1,2,3,4,5,6]
    a.range.assert = (0..4)
    b.range.assert = (0..5)
    a.range(2,4).assert = (1..3)
    b.range(2,3).assert = (1..2)
    b.range(4,2).assert = (3..1)

## Indexable#first!

    a = [1,2,3]
    a.first!.assert = 1
    a.assert = [2,3]

## Indexable#last!

    a = [1,2,3]
    a.last!.assert = 3
    a.assert = [1,2]