----- Forwarded message from Brad Lhotsky <[EMAIL PROTECTED]> -----
From: Brad Lhotsky <[EMAIL PROTECTED]>
To: Rodent of Unusual Size <[EMAIL PROTECTED]>
Subject: Re: defining 'constants' at run time
Date: Tue, 2 Mar 2004 14:01:06 -0500
User-Agent: Mutt/1.4i
Message-ID: <[EMAIL PROTECTED]>
Any reason why it has to be a constant? I'm pretty sure you could
either find or write a Tie:: class that would only allow you to set the
value of a variable, or hash key once. That might be a more
maintainable solution.
The code for this wouldn't be difficult if it doesn't already exist:
my $var = undef;
tie $var, 'Tie::Constant';
$var = 250;
$var = 1; # warning attempt to modify read-only value!
print "$var\n"; # '250\n';
?
On Tue, Mar 02, 2004 at 05:42:07AM -0500, Rodent of Unusual Size wrote:
> tell me to piss off for asking here, if you like, but i'm not on
> any other perl lists due to traffic. besides, the responses and
> advice here have been higher quality. :-)
>
> i want to be able to define 'constants' in a module at run time,
> rather than at compile time. 'use constant' does it too early.
> for example:
>
> use Foo;
> my $foo = new Foo;
> $foo->mkconst('DOH', 25);
> printf("DOH=%d\n", DOH);
>
> the result i'm looking for is 'DOH=25' on stdout. however,
> all i've managed to get is either an error about DOH being a
> non-integer, or an unopened filehandle. i've tried things
> like having mkconst() do
>
> my $name = caller() . "::$_[0]";
> eval("\*$name = sub () { $_[1]; }");
>
> and that will work -- IFF the caller refers to DOH as &DOH.
>
> evidently the usage of DOH in the caller has already been fetched
> from the symbol table (and found wanting) before the method has
> been called. is there any way to defeat that?
>
> (i hope i'm explaining this lucidly.)
> --
> #ken P-)}
>
> Ken Coar, Sanagendamgagwedweinini http://Ken.Coar.Org/
> Author, developer, opinionist http://Apache-Server.Com/
>
> "Millennium hand and shrimp!"
>
>
--
Brad Lhotsky <[EMAIL PROTECTED]>
----- End forwarded message -----
--
Brad Lhotsky <[EMAIL PROTECTED]>
