ConvertTo-LaTeX.ps1

# Powershell script to export tables from excel to LaTeX markup

function ConvertTo-Latex($inputFile, $sheetName, $startX, $startY, $endX, $endY, $outputFile)
{

	function Get-LatexTableOptions($columnCount)
	{
		$options = "|"

		for($i = 0; $i -lt $columnCount; $i = $i + 1)
		{
			$options = $options + " c |"
		}

		return $options
	}

	# Load Powerpoint Interop Assembly
	[Reflection.Assembly]::LoadWithPartialname("Microsoft.Office.Interop.Excel") > $null
	[Reflection.Assembly]::LoadWithPartialname("Office") > $null

	$msoFalse =  [Microsoft.Office.Core.MsoTristate]::msoFalse
	$msoTrue =  [Microsoft.Office.Core.MsoTristate]::msoTrue
	
	# start Excel
	$application = New-Object "Microsoft.Office.Interop.Excel.ApplicationClass" 

	# Make sure inputFile is an absolte path
	$inputFile = Resolve-Path $inputFile
	$outputFile = [System.IO.Path]::GetFullPath($outputFile)


	$workbook = $application.Workbooks.Open($inputFile)
	$sheet = $workbook.Worksheets.Item($sheetName)

	$options = Get-LatexTableOptions ($endX - $startX + 1)	
	Out-File $outputFile -InputObject "\begin{tabular}{$($options)} \firsthline" -Encoding ASCII
	$y = $startY
	
	while($y -le $endY) 
	{
		 $line = "`t"
		 $x = $startX
		 while($x -le $endX)
		 {
			$value = $sheet.Cells.Item($y, $x).Text
			if($x -eq $startX)
			{
				$line = $line + $value
			}
			else
			{
				$line = $line + "  &  " + $value
			}
			$x++
		 }

		$line = $line + "  \\\hline"
		Out-File $outputFile -InputObject $line -Append -Encoding ASCII

		$y++
	}
	Out-File $outputFile -InputObject "\end{tabular}" -Append -Encoding ASCII


	$sheet = $null

	$workbook.Close($msoFalse)
	$workbook = $null

	if($application.Windows.Count -eq 0)
	{
		$application.Quit()
	}

	$application = $null

	# Make sure references to COM objects are released, otherwise powerpoint might not close
	# (calling the methods twice is intentional, see https://msdn.microsoft.com/en-us/library/aa679807(office.11).aspx#officeinteroperabilitych2_part2_gc)
	[System.GC]::Collect();
	[System.GC]::WaitForPendingFinalizers();
	[System.GC]::Collect();
	[System.GC]::WaitForPendingFinalizers();

}