function Get-PowerShellGuide

{

[CmdletBinding(DefaultParameterSetName='NoTopic')]

[Alias('Get-PSGuide')]

param(

[Parameter(Mandatory,ParameterSetName='Topic',ValueFromPipelineByPropertyName)]

[Alias('TopicName')]

[string]

$Topic

)

process {

if ($PSCmdlet.ParameterSetName -eq 'NoTopic') {

if (-not $script:CachedPowerShellGuide) {

$guideTopics =

Get-ChildItem -Path $PSScriptRoot -Filter Guide |

Get-ChildItem -Recurse |

Where-Object Extension -in '.md' |

Where-Object FullName -notlike '*_site*'

$guideTopics = @(all in $guideTopics are 'PowerShell Guide Topic File')

$myModuleVersion = $MyInvocation.MyCommand.ScriptBlock.Module.Version

$script:CachedPowerShellGuide = [PSCustomObject]@{

PSTypeName = 'PowerShell.Guide'

Version = $myModuleVersion

AllTopics = $guideTopics

AllDemos = $guideDemos

}

}

$script:CachedPowerShellGuide

}

if ($PSCmdlet.ParameterSetName -eq 'Topic') {

$psGuide = Get-PowerShellGuide

$psGuide.AllTopics |

Where-Object Aliases -like $Topic

}

}

}