SPUG: Answered my own question

[Jeremy Devenport]

>From 'perldoc eval':
    In both forms, the value returned is the value of
    the last expression evaluated inside the mini-pro-
    gram

I think what you actually want to do is:

BEGIN {
    eval {require FOO}; # this could just as easily be 'use' instead of
'require' but this skips trying to import
    if ($@) { # use $@ to catch exceptions from the eval
        $hasfoo = 0;
    }
    else {
        $hasfoo = 1;
    }
}

In your second attempt you just happened to get the right result, it is
entirely coincidental. Try switching the module name to something like
"frobaz" and see if you still get what you expect. What you are actually
doing is setting $hasQuote based on whether or not the string "use
Finance::YahooQuote" is a true value, most strings are.

Jeremy

-----Original Message-----
From: owner-spug-list at pm.org [mailto:owner-spug-list at pm.org]On Behalf Of
Creede Lambard
Sent: Thursday, February 15, 2001 12:44 PM
To: spug-list at pm.org
Subject: SPUG: Answered my own question


Here's the code that works:

BEGIN
{
    $hasQuote = 1;
    unless ( eval { "use Finance::YahooQuote" })        # note the quotes!!
        { $hasQuote = 0; }
}

print $hasQuote;



The trick was using a STRING in the eval rather than a straightforward use
statement.

Now I feel silly, but thanks anyway.

-- Creede


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