2016 Update

Task/Balanced-brackets/PowerShell/balanced-brackets-3.psh

@@ -0,0 +1,57 @@
+function Test-BalancedBracket
+{
+  <#
+    .SYNOPSIS
+        Tests a string for balanced brackets.
+    .DESCRIPTION
+        Tests a string for balanced brackets. ("<>", "[]", "{}" or "()")
+    .EXAMPLE
+        Test-BalancedBracket -Bracket Brace -String '{abc(def[0]).xyz}'
+        Test a string for balanced braces.
+    .EXAMPLE
+        Test-BalancedBracket -Bracket Curly -String '{abc(def[0]).xyz}'
+        Test a string for balanced curly braces.
+    .EXAMPLE
+        Test-BalancedBracket -Bracket Curly -String ([System.IO.File]::ReadAllText('.\Foo.ps1'))
+        Test a file for balanced curly braces.
+    .LINK
+        http://go.microsoft.com/fwlink/?LinkId=133231
+  #>
+    [CmdletBinding()]
+    [OutputType([bool])]
+    Param
+    (
+        [Parameter(Mandatory=$true)]
+        [ValidateSet("Angle", "Brace", "Curly", "Paren")]
+        [string]
+        $Bracket,
+
+        [Parameter(Mandatory=$true)]
+        [AllowEmptyString()]
+        [string]
+        $String
+    )
+
+    $notFound = -1
+
+    $brackets = @{
+        Angle = @{Left="<"; Right=">"; Regex="^[^<>]*(?>(?>(?'pair'\<)[^<>]*)+(?>(?'-pair'\>)[^<>]*)+)+(?(pair)(?!))$"}
+        Brace = @{Left="["; Right="]"; Regex="^[^\[\]]*(?>(?>(?'pair'\[)[^\[\]]*)+(?>(?'-pair'\])[^\[\]]*)+)+(?(pair)(?!))$"}
+        Curly = @{Left="{"; Right="}"; Regex="^[^{}]*(?>(?>(?'pair'\{)[^{}]*)+(?>(?'-pair'\})[^{}]*)+)+(?(pair)(?!))$"}
+        Paren = @{Left="("; Right=")"; Regex="^[^()]*(?>(?>(?'pair'\()[^()]*)+(?>(?'-pair'\))[^()]*)+)+(?(pair)(?!))$"}
+    }
+
+    if ($String.IndexOf($brackets.$Bracket.Left)  -eq $notFound -and
+        $String.IndexOf($brackets.$Bracket.Right) -eq $notFound -or  $String -eq [String]::Empty)
+    {
+        return $true
+    }
+
+    $String -match $brackets.$Bracket.Regex
+}
+
+
+'', '[]', '][', '[][]', '][][', '[[][]]', '[]][[]' | ForEach-Object {
+    if ($_ -eq "") { $s = "(Empty)" } else { $s = $_ }
+    "{0}: {1}" -f  $s.PadRight(8), "$(if (Test-BalancedBracket Brace $s) {'Is balanced.'} else {'Is not balanced.'})"
+}