问点(.)之间的区别是什么？PowerShell中的符号(&)？

EN

- [**`&`****, the** _**call operator**_](https://learn.microsoft.com/powershell/module/microsoft.powershell.core/about/about_operators#call-operator-), executes scripts and functions in a _child_ scope, which is the _**typical**_ **use case**: functions and scripts are typically expected to **execute** _**without side effects**_:

    - The variables, (nested) functions, aliases defined in the script / function invoked are local to the invocation and go out of scope when the script exits / function returns.

    - Note, however, that **even a script run in a** _**child**_ **scope can affect the caller's environment**, such as by using `Set-Location` to change the current location, explicitly modifying the parent scope (`Set-Variable -Scope 1 ...`) or the global scope (`$global:...`) or defining process-level environment variables.

- [**`.`****, the** _**dot-sourcing operator**_](https://learn.microsoft.com/powershell/module/microsoft.powershell.core/about/about_operators#dot-sourcing-operator-), executes scripts and functions in the _current scope_ and is **typically used to** _**modify the caller's scope**_ **by adding functions, aliases, and possibly variables** _**for later use**_. For instance, this mechanism is used to load the `$PROFILE` file that initializes an interactive session.

# get and variable in module scope
$m = get-module counter
& $m Get-Variable count
& $m Set-Variable count 33

# see func def
& $m Get-Item function:Get-Count

# redefine func in memory
& $m {
  function script:Get-Count
  {
    return $script:count += $increment * 2
  }
}

# get original func def on disk
Import-Module .\counter.psm1 -Force

# run with commandinfo object
$d = get-command get-date
& $d

# call anonymous function
& {param($x,$y) $x+$y} 2 5

# same with dot operator
. {param($x,$y) $x+$y} 2 5