powershellvariablesscopepreferences

Powershell: is there a Scope Preference for Variables?

Morning guys, hopefully just a quick one. Is there a Scope Preference for Variables like there is for some other settings ($ErrorActionPreference, etc)? I'm working on a script that has a bunch of functions that call on information created in each other and I'm just looking to avoid writing $Script: or $Global: in front of each variable everytime (I'm being lazy I know)

Solution

  • Is there a Scope Preference for Variables like there is for some other settings ($ErrorActionPreference, etc)?

    No, scoping behavior is part of the language's core runtime semantics and is not configurable.

    I'm working on a script that has a bunch of functions that call on information created in each other and I'm just looking to avoid writing $Script: or $Global: in front of each variable everytime

    You don't need it everytime - you only need the scope modifier when you're writing to a parent scope.

    Resolution of variables for reading will fall back through parent scopes and eventually the global scope, until a matching variable is found:

    # variable defined at script scope, functions defined in here will fall back to resolving this when `$Config` is referenced
$Config = @{
  'setting' = 'initialValue'
}

function Update-Config {
  # Scope modifier is only necessary when "writing up" through the scope stack
  $script:Config = @{
    setting = 'updatedValue'
  }
}

function Do-Stuff {
  $setting = $Config['setting'] # no need to use script: here

  Write-Host "About to do something with '$setting'"
}

Do-Stuff
Update-Config
Do-Stuff

    Executing the above in a script file will print:

    About to do something with 'initialValue'
About to do something with 'updatedValue'

    Note that for functions bound to a module, the script: scope is shared across the module - writing to $script:Variable in one module function will cause resolution of non-local $Variable to resolve correctly in any other function in the same module

    For more information about scoped variable resolution, consult the about_Scopes help file