In Single Module Scenario: Running Set-Var returns 10.

# m.psm1

function Set-Var {
    $MyVar = 10
    Get-Var
}

function Get-Var {
    $MyVar
}

In Nested Modules Scenario: Running Set-Var does not return any value.

# m1.psm1

function Get-Var {
    $MyVar
}

# m.psm1

Import-Module .\m1.psm1

function Set-Var {
    $MyVar = 10
    Get-Var
}

How do I achieve the same effect as a single module with nested modules? Using $script:MyVar also does not work. However, I would like to keep the scope of the variable local to enable concurrent executions with different values.

CodePudding user response：

Your code doesn't work because local variables are not inherited by functions in nested module context.

You can do this instead:

function Get-Var {
    [CmdletBinding()] param()
    $PSCmdlet.SessionState.PSVariable.Get('MyVar').Value
}

• Use the CmdletBinding attribute to create an advanced function. This is a prerequisite to use the automatic $PSCmdlet variable, which we need in the next step.
• Use its SessionState.PSVariable member to get or set a variable from the parent (module) scope.
• Note this works only when the caller is in a different module or script.
• This answer shows an example how to set a variable in the parent (module) scope.
• See also: Is there any way for a powershell module to get at its caller's scope?