Date: Mon, 10 Sep 2001 14:08:50 -0500
From: Michael Carman <mjcarman@home.com>
Subject: Re: Probelm with undefined atgumnets
Message-Id: <3B9D0FC2.1E061C9E@home.com>

Stan Brown wrote:
> 
> A kind member of this group showed me a neat trick to print out the
> arguments to a given function. It goes like this:
> 
> join ', ', map { "Arg$_ ->$_[$_]<-" } 0 .. $#_;
> 
> This works great _except_ when I pass in undef for an argumentm then
> I get a warning about concatenating an unitliazed variable.
> 
> How can I improve thsi to allow for this case?

Two options:

Disable warnings for just that block:

{
    local $^W;
    print join ', ', map { "Arg$_ ->$_[$_]<-" } 0 .. $#_;
}

Or catch the undef and map it into something else:

print join ', ', map {defined($_[$_])
    ? "Arg$_ ->$_[$_]<-"
    : "Arg$_ ->*UNDEF*<-"
} 0 .. $#_;


-mjc