Implementing APL shape/rank (⍴/⍴⍴) functions in PowerShell. This is a rough first cut.

ReShape.ps1

# APL Rank
filter ⍴⍴ {
  param(
    [Parameter(Position=0, Mandatory=$true, ValueFromPipeline=$false)] $ω
  )
  process {
    if($ω -is [system.array]){
      $ω.rank
    } else{
      "⍬"
    }
  }
}

# APL Shape and ReShape
function ⍴ {
  [CmdletBinding()]
  param(
    [Parameter(Position=1, Mandatory=$false, ValueFromPipeline=$true)] $α,
    [Parameter(Position=0, Mandatory=$true, ValueFromPipeline=$false)] $ω
  )
  begin {
    $pipeCapture = @() 
  }
  process {
    $pipeCapture += $_
  }
  end {
    $α = $pipeCapture
    if($α) {
      $res = new-object "System.Object[$(',' * ($α.Length-1))]" $α

      $sourceIndices = ?: { (⍴⍴ $ω) -eq 1 } { (0..($ω.Length-1)) } { (CartesianProduct ((⍴ $ω) | % { ,(0..($_-1)) })) }
      $index = 0
      $targetIndices = ?: { $α.Length -eq 1} { ,(0..($α[0]-1)) } { (CartesianProduct ($α | % { ,(0..($_-1)) })) }

      foreach($targetIndex in $targetIndices) {
        $sourceIndex = $sourceIndices[($index++ % $sourceIndices.Length)]
        $res[$targetIndex] = $ω[$sourceIndex]
      }

      return ,$res
    } else {
      if(($rank = ⍴⍴ $ω) -ne "⍬") {
        @(0..($rank-1) | % {$ω.GetLength($_)})
      } else {
        "⍬"
      }
    }
  }
}

Usage.ps1

$a = @(2,3)
$b = new-object "System.Int32[,]" 4,2
$c = new-object "System.Int32[,,]" 5,4,3
$s = 5

Write-Host "The rank of a 1 dim: " (⍴⍴ $a)
Write-Host "The rank of a 2 dim: " (⍴⍴ $b)
Write-Host "The rank of a 3 dim: " (⍴⍴ $c)
Write-Host "The rank of a scalar: " (⍴⍴ $s)

Write-Host ("The shape of the 1 dim: {0}" -f (⍴ $a))
Write-Host ("The shape of the 2 dim: {0} {1}" -f (⍴ $b))
Write-Host ("The shape of the 3 dim: {0} {1} {2}" -f (⍴ $c))
Write-Host ("The shape of the scalar: {0}" -f (⍴ $s))

$shape = @(3,3)
$data = @(1,2,3,4,5,6,7,8,9)

[Object[,]]$result = ($shape | ⍴ $data)

$sb = New-Object -TypeName "System.Text.StringBuilder"

for($i = 0; $i -lt $result.GetLength(0); $i++) {
  for($j = 0; $j -lt $result.GetLength(1); $j++) {
    $cur = $result[$i,$j]
    [void]$sb.Append($cur)
    [void]$sb.Append(" ")
  }
  [void]$sb.Append([Environment]::NewLine)
}
Write-Host $sb.ToString()


$sb = New-Object -TypeName "System.Text.StringBuilder"
$shape2 = @(9)

[Object[]]$result2 = ($shape2 | ⍴ $result)
for($i = 0; $i -lt $result2.GetLength(0); $i++) {
    $cur = $result2[$i]
    [void]$sb.Append($cur)
    [void]$sb.Append(" ")
  }

[void]$sb.Append([Environment]::NewLine)
Write-Host $sb.ToString()

Utils.ps1

set-alias ?: Invoke-Ternary
filter Invoke-Ternary ([scriptblock]$conditional, [scriptblock]$trueBlock, [scriptblock]$falseBlock) {
  if (& $conditional) {
    & $trueBlock
   } else { 
    & $falseBlock 
   }
}

filter CartesianProduct($itemSource) {
  switch (,$itemSource) {
    $null { 
      break 
    }
    { $_.Count -eq 1 } {
      $_
    }
    { $_.Count -gt 1 } {
      $res = @()
      foreach ($α in $_[0]) {
        foreach ($ω in (CartesianProduct $_[1..($_.Count - 1)])) {
          $res += ,(?: {$ω -is [Object[]]}{,$α + $ω}{,@($α, $ω)})
        }
      }
      ,$res
    }
  }
}