Why does an argument $args after = sign not get expanded? ($args as parameter to jvm typical -D switch) - powershell

Question

I have the following definition in my *profile.ps1 file:
if(Test-Path $env:M2_HOME){
function mvn{
$cmd = "$env:M2_HOME\bin\mvn.bat"
& $cmd $args
}
}
When I define a function using this function in powershell like:
function d { mvn help:describe $args }
using like:
d -Dplugin=jar
everything is fine as opposed to defining the latter as:
function d { mvn help:describe -Dplugin=$args }
using like:
d jar
Is there some builtin to handle this corner case?

Answer 1

It looks like you just need to make sure you're passing the arguments as strings and ensure they're evaluated first:
function mvn{
$cmd = "$env:M2_HOME\bin\mvn.bat"
& $cmd $args
}
function d { mvn "help:describe" "-Dplugin=$($args)" }

Answer 2

for get argument through call function you should use like this
function test {
write-host $args[0]
write-host $args[1]
}
test stackoverflow powershell
output
stackoverflow
powershell
stackoverflow is first argument passed to function and powershell is second argument passed to function
for every argument passed to function
function test {
foreach ($a in $args){
write-host "output:$args"
}
}
test 1 2 3 4 5 6 7 8
output:
test 1 2 3 4 5 6 7 8
output:1 2 3 4 5 6 7 8
output:1 2 3 4 5 6 7 8
output:1 2 3 4 5 6 7 8
output:1 2 3 4 5 6 7 8
output:1 2 3 4 5 6 7 8
output:1 2 3 4 5 6 7 8
output:1 2 3 4 5 6 7 8
output:1 2 3 4 5 6 7 8
for your function
if(Test-Path $env:M2_HOME){
function mvn{
$cmd = "$env:M2_HOME\bin\mvn.bat"
foreach ($arg in $args) {
& $cmd $args}
}
}

Answer 3

Someone seems to have made a similar observation:
The reason seems -D being a special character in powershell more or less marking where exactly each particluar special option string determined by -D ends, at least this modification to my calling function then works for me:
function x {mvn help:describe `-Dplugin=$args}
Sure it would be nice to handle such occasions in the hosting function somehow (mvn definition in my *profile.ps1), but that solutions rather seems out of scope of my question.