Vista Tutorial - Multiple trap handlers in a function: variable scoping issues

I'm trying to write the PowerShell equivalent of this:-


void MyMethod ()
{
FileInfo fi = null;
try
{
fi = new FileInfo (@"C:\out.txt");
}
catch (Exception ex)
{
MessageBox.Show (ex.Message);
return;
}


FileInfo fi1 = null;
try
{
fi1 = new FileInfo (@"C:\out1.txt");
}
catch (Exception ex)
{
MessageBox.Show (ex.Message);
return;
}


// use 'fi' and 'f1'; e.g. read their Exists properties
MessageBox.Show (fi.Exists.ToString ());
MessageBox.Show (fi1.Exists.ToString ());
}


-------------------------------------------------------

So far I have this:-


function Main
{
new-variable fi -value $null -option "AllScope"
&{
trap
{
write-host "Exception handler 1" + $_.Exception.Message
continue
}
.{
$fi = new-object -typename System.IO.FileInfo -argumentlist "C:\out.txt"
}
}
if ($fi -eq $null)
{
return
}


new-variable fi1 -value $null -option "AllScope"
&{
trap
{
write-host "Exception handler 2" + $_.Exception.Message
continue
}
.{
$fi1 = new-object -typename System.IO.FileInfo -argumentlist
"C:\out1.txt"
}
}
if ($fi1 -eq $null)
{
return
}


write-host $fi.Exists
write-host $fi1.Exists
}

.. Main

write-host $fi.Exists
write-host $fi1.Exists


-------------------------------------------------------

I.e.
- use script blocks in order to have multiple trap handlers in the same
function
- use the new-variable cmdlet with the "AllScope" option to ensure that
'fi' and
'fi1' exist at function scope and script block scope

Unfortunately, "AllScope" means just that. Hence the two write-host
statements after
the call to Main do work, but ideally they should not.

Am I on the right track? Is there a way to keep the two variables at
function scope?
Is there a fundamentally better/different way than my approach?

TIA

Andrew

Er, I think I solved it. I change this:-
. Main
to this:-
& Main

Then variables created by the function are at function scope.

I'd still be interested to know if I've taken the right approach to having
multiple trap handlers in a function. Thanks!

Andrew

OTOH... the following works, without having to use 'new-variable'. Sometimes
dot-sourcing is the right thing to do, and at other times it's not. You
really have to know. I'm getting there...

function Main
{
.{
trap
{
write-host "Exception handler 1" + $_.Exception.Message
continue
}
.{
$fi = new-object -typename System.IO.FileInfo -argumentlist "C:\out.txt"
}
}
if ($fi -eq $null)
{
return
}


.{
trap
{
write-host "Exception handler 2" + $_.Exception.Message
continue
}
.{
$fi1 = new-object -typename System.IO.FileInfo -argumentlist
"C:\out1.txt"
}
}
if ($fi1 -eq $null)
{
return
}


write-host $fi.Exists
write-host $fi1.Exists

}

Main # the same as doing: & Main