Vista - supplying help option and throwing on empty option

Just wanted to poll the collective brain on the best way to go about this . . .

I have a script which takes a number of options at run-time (of which
defaults are stored in 'param'). One of the options is -help which
gives the user a nice help description. However, one of the options
should throw an error if left blank. But if the user issues -help and
the required option is blank then, of course, an exception is thrown.

Is there anything funky I can do within the param collection to get the
desired functionality?

Cheers,
n

You could make -help a [switch] parameter and check its state to determine
whether or not to throw the exception if -xOption is $null:

param ([switch]$help, $xOption, ...)
if ($xOption -eq $null) {
if ($help) {
# change $help's state to avoid showing it twice
$help = (!$help)
"show help"
}
else {"throw exception"}
}

# show help if its state is $true and $xOption is not $null
if ($help) {"show help"}

--
Kiron

"Neil Chambers" <n3llyb0y@aol.com> wrote in message
news:2007060815331116807-n3llyb0y@aolcom...
> Just wanted to poll the collective brain on the best way to go about this
> . . .
>
> I have a script which takes a number of options at run-time (of which
> defaults are stored in 'param'). One of the options is -help which gives
> the user a nice help description. However, one of the options should throw
> an error if left blank. But if the user issues -help and the required
> option is blank then, of course, an exception is thrown.
>
> Is there anything funky I can do within the param collection to get the
> desired functionality?

You should test the content of your option outside of the param statement.
To avoid running the test before showing the help when -help is specified,
you can write the help section first and finish it with an exit statement so
any further code is skipped. That would look like this:

param ($option1, [switch]$help)
if ($help) {"Help!";exit}
if (! $option1) {throw "Option1 cannot be blank!"}
....

Hope that helps,
Jaqcues

Thank you, Kiron and Jacques :-) Both excellent options.

n