Dynamically nesting CAML query statements

Here is a short PowerShell function that can be used when you need to dynamically generate CAML queries with many logically joined statements. I actually adapted it from a C# implementation I wrote (which is probably more useful…) but as you can rewrite it in C# very easily I won’t bother bother posting it twice.

As CAML logical join operators (And, Or) can only compare two statements, when many statements need to be compared you must nest them which is what this function achieves. The $join parameter should be passed as “And” or “Or” and the $fragments parameter should be passed as an array of CAML statement strings such as:
@("<Eq><FieldRef Name='Title' /><Value Type='Text'>title</Value></Eq>", "<Eq><FieldRef Name='FileLeafRef' /><Value Type='Text'>name.docx</Value></Eq>")

# Define method for nesting caml query statements
function GetNestedCaml([array]$fragments, [string]$join)
{
    if ($fragments.Length -lt 1)
    {
        return [string]::Empty
    }
    elseif ($fragments.length -eq 1)
    {
        return $fragments[0]
    }
    elseif ($fragments.length -eq 2)
    {
        return "<$join>" + $fragments[0] + $fragments[1] + "</$join>"
    }
    $joinFrags = @()
     $baseJoinCount = [int][Math]::Floor($fragments.length / 2)
    for ($i = 0; $i -lt $baseJoinCount; $i++)
    {
        $baseIndex = (2 * $i)
        $fragsToJoin = @($fragments[$baseIndex], $fragments[$baseIndex + 1])
        $joinFrag = GetNestedCaml $fragsToJoin $join
        $joinFrags += $joinFrag
    }
    if ($fragments.length % 2 -ne 0)
    {
        $joinFrags += $fragments[$fragments.length - 1]
    }
    return GetNestedCaml $joinFrags $join
}

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