A PowerShell function to easily navigate to a folder within a $BaseDir from anywhere using a dynamic parameter for tab completion. I use it to jump to repos in my `c:\sources` directory.

profile.ps1

$BaseDir = "C:\sources"

Function go {
    [CmdletBinding()]
    param ()
    DynamicParam {
        # Set the dynamic parameters' name
        $ParameterName = 'Repo'

        # Create the dictionary
        $RuntimeParameterDictionary = New-Object System.Management.Automation.RuntimeDefinedParameterDictionary

        # Create the collection of attributes
        $AttributeCollection = New-Object System.Collections.ObjectModel.Collection[System.Attribute]

        # Create and set the parameters' attributes
        $ParameterAttribute = New-Object System.Management.Automation.ParameterAttribute
        $ParameterAttribute.Mandatory = $true
        $ParameterAttribute.Position = 0

        # Add the attributes to the attributes collection
        $AttributeCollection.Add($ParameterAttribute)

        # Generate and set the ValidateSet
        $arrSet = Get-ChildItem $BaseDir\*, $BaseDir\*\* | Where-Object { $_.PSIsContainer } | Select-Object -Property Name,FullName
        $ValidateSetAttribute = New-Object System.Management.Automation.ValidateSetAttribute($arrSet | Select-Object -ExpandProperty Name)

        # Add the ValidateSet to the attributes collection
        $AttributeCollection.Add($ValidateSetAttribute)

        # Create and return the dynamic parameter
        $RuntimeParameter = New-Object System.Management.Automation.RuntimeDefinedParameter($ParameterName, [string], $AttributeCollection)
        $RuntimeParameterDictionary.Add($ParameterName, $RuntimeParameter)
        return $RuntimeParameterDictionary
    }

    begin {
        # Bind the parameter to a friendly variable
        $Repo = $PsBoundParameters[$ParameterName]
    }
    process {
        $location = $arrSet | Where-Object { $_.Name -eq $Repo } | Select-Object -ExpandProperty FullName
        Set-Location $location
    }
}