PowerShell "Spell Check"

gistfile1.ps1

Add-Type @"
using System.Linq;
using System;
public class EditDistance {
    public static int CheckEditDistance (string original, string modified)
    {
        int len_orig = original.Length;
        int len_diff = modified.Length;

        var matrix = new int[len_orig + 1, len_diff + 1];
        for (int i = 0; i <= len_orig; i++)
            matrix[i,0] = i;
        for (int j = 0; j <= len_diff; j++)
            matrix[0,j] = j;
        
        for (int i = 1; i <= len_orig; i++) {
            for (int j = 1; j <= len_diff; j++) {
                int cost = modified[j - 1] == original[i - 1] ? 0 : 1;
                var vals = new int[] {
                    matrix[i - 1, j] + 1,
                    matrix[i, j - 1] + 1,
                    matrix[i - 1, j - 1] + cost
                };
                matrix[i,j] = vals.Min ();
                if (i > 1 && j > 1 && original[i - 1] == modified[j - 2] && original[i - 2] == modified[j - 1])
                    matrix[i,j] = Math.Min (matrix[i,j], matrix[i - 2, j - 2] + cost);
            }
        }
        return matrix[len_orig, len_diff];
    }
}
"@ -Language CSharp -ReferencedAssemblies System.Xml, System.Xml.Linq, System.Linq, System.Runtime.Extensions

<#
	.SYNOPSIS
		Provides basic "Spell Checking" 
	
	.DESCRIPTION
		Returns the $ResultSize strings from the dictionart that are closest to the BaseString using the Levenshtein distance
	
	.PARAMETER BaseString
		The string to be checked for closes matches
	
	.PARAMETER Dictionary
		The dictionary used for lookup
	
	.PARAMETER ResultSize
		The number of results to be returned
	
	.EXAMPLE
		PS C:\> Get-ClosestString -BaseString 'Value1' -Dictionary $value2
	
	.NOTES
		Additional information about the function.
#>
function Get-ClosestString {
	[CmdletBinding()]
	param
	(
		[Parameter(Mandatory = $true)]
		[String]$BaseString,
		[Parameter(Mandatory = $true)]
		[String[]]$Dictionary,
		[int]$ResultSize = 2
	)
	
	$BaseString = $BaseString.ToLower()
	
	$Comparisons = $Dictionary | ForEach-Object {
		[PSCustomObject]@{
			Distance = [EditDistance]::CheckEditDistance($BaseString, $_.ToLower())
			Word     = $_
		}
	}
	
	$Comparisons | Sort-Object Distance | Select-Object -First $ResultSize
}