grrrr

docs/document/Csharp Design Patterns/docs/Behavioural/Mediator.md

@@ -0,0 +1,9 @@
+# Mediator
+
+Facilitates communications between components.
+
+## Motivation
+
+- Communications between clients on any presence or absence. Like a chatroom or online games.
+
+So mediator usually as a central facility to handle communications from different clients, clients are not required to know each other.

docs/document/Powershell/docs/Alias.md

@@ -0,0 +1,60 @@
+# Alias
+
+## Set an Alias
+
+```ps1
+New-Alias <alias> <cmd_name>
+```
+
+> [!note]
+> `New-Alias` throws when the alias already exist while `Set-Alias` will overrides it.
+
+## Override an Alias
+
+```ps1
+Set-Alias <alias> <cmd_name>
+```
+
+## Checkout Alias
+
+- Check out by alias
+
+```ps1
+Get-Alias <alias>
+```
+
+Or use `Get-Command`
+
+```ps1
+Get-Command <alias>
+```
+
+- Check out by command name
+
+```ps1
+Get-Alias -Definition <cmd_name>
+```
+
+## Builtin Aliases
+
+Powershell ships with some builtin aliases, checkout by this command:
+
+```ps1
+Get-Alias | Where-Object { $_.Options -match 'ReadOnly|Constant' }
+```
+
+> [!note]
+> Do not use custom aliases for public repository.
+
+## Differ from Bash
+
+Alias in powershell is only a name alias for a command, it can never take any predetermined parameters or flags like in bash.
+
+```sh
+alias gl='git log' # fine
+```
+
+```ps1
+New-Alias gl 'git log' # not allowed! # [!code error] 
+```
+

docs/document/Powershell/docs/Overview.md

@@ -0,0 +1,4 @@
+# Overview
+
+- Dynamic typing
+- Case insensitive

docs/document/Powershell/docs/Powershell as a Language/Function.md

@@ -2,17 +2,38 @@
 
 ## Parameter
 
-There's no positional parameters, it's a table-like definition, can be specified with any order.
 Parameters are wrapped inside a function block with `param(...)`
 
 ```ps1
 function Foo {
     param (
-        [string]$foo
+        $Foo
     )
 }
 ```
 
+> [!NOTE]
+> 
+> Default type of a parameter is `System.Object`.
+
+### Positional Parameter
+
+Positional parameters allows passing values with explicit names.
+
+```ps1
+function Foo {
+    param (
+        [string] $Foo,
+        [string] $Bar
+    )
+    
+    Write-Output "$Foo $Bar"
+}
+
+Foo -Foo foo -Bar bar
+Foo foo bar # it's the same # [!code highlight] 
+```
+
 ### Default Parameter
 
 ```ps1
@@ -32,13 +53,13 @@ While `switch` will remain `$false` when unspecified.
 ```ps1
 function Foo {
     param (
-        [switch]$foo
-        [bool]$bar
+        [switch]$Foo
+        [bool]$Bar
     )
 }
 
 # this is why we should use `switch` instead.
-Foo -foo -bar $true # [!code highlight]
+Foo -Foo -Bar $true # [!code highlight]
 ```
 
 ### Required Parameter
@@ -52,6 +73,25 @@ param (
 )
 ```
 
+### Parameter Alias
+
+Parameters can have aliases. It's not needed for most of time though since pwsh can distinguish option by leading string.
+
+```ps1
+function Person {
+    param (
+        [Alias("n")] # [!code highlight] 
+        [string]$Name,
+
+        [Alias("a")] # [!code highlight] 
+        [int]$Age
+    )
+    Write-Host "Name: $Name, Age: $Age"
+}
+
+Person -n "Alice" -a 30 # [!code highlight] 
+```
+
 ## Lifetime
 
 - Function should be define before it was called.

docs/document/Powershell/docs/Terminology & Naming.md

@@ -0,0 +1,10 @@
+#
+
+## Terminology
+
+Powershell has its own terminologies besides other shells like bash.
+It's a shell integrated with .NET, it's not a independent platform.
+
+- `cmdlet`: builtin utils inside powershell, implemented using other languages like `C#`.
+- `function`: a command implemented using powershell language itself.
+- `application`: external executables.