In Powershell set-variable not overriding Script Parameters? Trying to read JSON and override script parameters using JSON

user_5632412 0
Viewed 35

I'm wondering about the following code. I use powershell to load the following json file called "tool.json":

{
  "1": {
    "Tool":           ["vhdl_component_packager"],
    "Name":           ["a1_stuff"],
    "Dir":            ["./source"],
    "Recurse":        ["true"],
    "ExcludeVhd":     ["*_tb.vhd"],
    "ExcludeEntity":  []
  }
}

Then when I execute my script I would expect the script to read the variables in the JSON file to override the parameters of the script, namely $Dir, and set it to ./source as shown in the JSON file. But that's not happening, instead its not change $Dir... I'm wondering how to fix it.


param(
    [string]$Dir = "."
)
function read_tool_json {
    $tool_json = "./tool.json"
    
    if (-not(test-path $tool_json)) {
        throw "Missing ./tool.json file"
    }       
    
    write-host "Reading file: $tool_json"
    $tool_json  = Get-Content -Raw $tool_json | ConvertFrom-Json
    
    foreach ($item1 in $tool_json.psobject.Properties) {
        write-host $item1.Name
        $top_name = $item1.Name
        $top_node = $tool_json.$top_name                
        foreach ($item2 in $top_node.psobject.Properties) {
           $elem_name = $item2.Name
           $elem_node = [array]$top_node.$elem_name             
           write-host "set-variable -name $elem_name -value $elem_node -scope global"
           set-variable -name $elem_name -value $elem_node -scope global -force
           $dir
        }           
    }       
}

read_tool_json

$script:Dir.GetType()

#QUESTION: how to get $script:Dir to equal "./source" from json file???
write-host "dir:($Dir)"
powershell
1 Answers

You've got a variable already defined at script scope called Dir:

param(
    [string]$Dir = "."
)

However, you are setting $Dir at global scope in your set-variable. You can see that if you add the following line to your script:

write-host "dir:($global:Dir)"

If you want to modify the the $Dir at script scope, then just remove the -scope global from your set-variable command, or change it to -scope script.

If you want to modify the the variable at script scope and also have it available at global scope, you'll have to do it explicitly at the end of your script:

$Dir = $global:Dir

Basciacally, you have 2 different variables here $global:Dir and $script:Dir.

zdan_43040
Related