Array Reversal in the pipeline

Sort-Reverse.ps1

# terrible
function Sort-VarReverse {
    # sorting rank = max
    $rank = [int]::MaxValue
    $input |Sort-Object {
        # decrement $rank in parent scope, reversing the input order
        (--(Get-Variable rank -Scope 1).Value)
    }
}

# bad
function Sort-ListReverse {
    begin {
        $list = [System.Collections.ArrayList]::new()
    }
    process {
        # insert at the top, reversing the input order
        $list.Insert(0,$_)
    }
    end {
        $list
    }
}

# pretty good
function Sort-StackReverse {
    begin {
        $stack = [System.Collections.Stack]::new()
    }
    process {
        $stack.Push($_)
    }
    end {
        # enumerating the stack returns the items in reverse input order
        $stack
    }
}

$twentyThousand = 1..20KB
Measure-Command {
    $twentyThousand |Sort-VarReverse
} |Select-Object @{N='Strategy';E={'Var'}},TotalMilliseconds
Measure-Command {
    $twentyThousand |Sort-ListReverse
} |Select-Object @{N='Strategy';E={'List'}},TotalMilliseconds
Measure-Command {
    $twentyThousand |Sort-StackReverse
} |Select-Object @{N='Strategy';E={'Stack'}},TotalMilliseconds

# Sample output
#
#   Strategy TotalMilliseconds
#   -------- -----------------
#   Var              1887.6106
#   List              175.9195
#   Stack              18.7144