Confused about why PowerShell treats a function different from a childitem, even if same type

Question

I'm confused about the difference between these two things:

$env:path

And

function path {$env:path}
path

Both return strings, according to get-member. Yet -match does not work the same on both.

If I use -match on $env:path, it works as I'd expect, returning true/false. But if I use -match on path (the new function) then it always returns the path, ignoring the -match.

I'm confused because both return strings and therefore ought to work the same. Does the function need to do something special to get the same result?

Answer 1

Have you tried something like

$(path) -match

I'm on Ubuntu here, so I can't verify. The $() causes the expression to be evaluated, and then I believe the -match should operate on the returned string

The reason I suggest this is that is seems to me that if you don't put the function call in the expression evaluator, the -match might be treated as a parameter to the path function, and ignored since the path function doesn't know about -match.

Answer 2

David is right. The difference is that -match is being treated as a parameter to the path function. So,

$(path) -match "foo"

or

(path) -match "foo" 

works equally well. The former is a subexpression, the latter a nested pipeline (usually same effect in cases like this, but there are subtle differences.)

Verify:

ps> function path {$env:path; write-host "parameters: $args"}
ps> path -match "foo"
(env:path expanded)
parameters: -match foo

-Oisin