Bug #72574 for Const-Fast: How can it be used with eval and/or require?

Mon Nov 21 02:15:16 2011 ANDK [...] cpan.org - Ticket created

Subject:

How can it be used with eval and/or require?

This works as documented: my @a = (1,2); use Const::Fast; const(@a); The following two variations do not work as I would expect: perl -e ' my @a = (1,2); require Const::Fast; Const::Fast::const(@a); ' Usage: Internals::SvREADONLY(SCALAR[, ON]) at ... perl -e ' my @a = (1,2); eval "use Const::Fast"; const(@a); ' Usage: Internals::SvREADONLY(SCALAR[, ON]) at ... What gives? If this is expected, could you document how to use Const::Fast with eval/require? I was trying to make it optional in one of my programs and I couldn't make sense from the examples above. Thanks,

Mon Nov 21 03:41:49 2011 $_ = 'spro^^*%*^6ut# [...] &$%*c>#!^!#&!pan.org'; y/a-z.@//cd; print - Correspondence added

On Mon Nov 21 02:15:16 2011, ANDK wrote: Show quoted text

> This works as documented: > > my @a = (1,2); > use Const::Fast; > const(@a); > > The following two variations do not work as I would expect: > > perl -e ' > my @a = (1,2); > require Const::Fast; > Const::Fast::const(@a); > ' > Usage: Internals::SvREADONLY(SCALAR[, ON]) at ... > > perl -e ' > my @a = (1,2); > eval "use Const::Fast"; > const(@a); > ' > Usage: Internals::SvREADONLY(SCALAR[, ON]) at ... > > What gives? If this is expected, could you document how to use > Const::Fast with eval/require? I was trying to make it optional in one > of my programs and I couldn't make sense from the examples above.

const() has a prototype. In your 2nd and 3rd examples, the prototype has not yet been seen when Perl compiles the call to const(). Calling it as &const(\@foo) or predeclaring it with a prototype will solve the problem.

Mon Nov 21 03:41:50 2011 The RT System itself - Status changed from 'new' to 'open'

Sun Nov 27 11:37:02 2011 LEONT [...] cpan.org - Taken

Sun Nov 27 11:37:05 2011 LEONT [...] cpan.org - Correspondence added

On Mon Nov 21 03:41:49 2011, SPROUT wrote: Show quoted text

> const() has a prototype. In your 2nd and 3rd examples, the prototype > has not yet been seen > when Perl compiles the call to const(). Calling it as &const(\@foo) > or predeclaring it with a > prototype will solve the problem.

Correct. I should probably add a clearer warning though, as the error is rather unhelpful. Leon

Tue Jan 31 10:27:29 2012 LEONT [...] cpan.org - Status changed from 'open' to 'resolved'