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Re^3: accessing stashes

by ikegami (Pope)
on Mar 01, 2019 at 19:14 UTC ( #1230729=note: print w/replies, xml ) Need Help??


in reply to Re^2: accessing stashes
in thread accessing stashes

$My::{$symbol} returns a glob.

*NAME{SLOT} accesses a glob's slot.
*BLOCK{SLOT} accesses a glob's slot.
*$NAME{SLOT} accesses a glob's slot.
EXPR->*{SLOT} accesses a glob's slot.[1]

So,

my $glob = $My::{$symbol}; $glob && *{ $glob }{CODE} $glob && *$glob{CODE} $glob && $glob->*{CODE}

  1. Requires Perl 5.24+. Available in Perl 5.20+ by adding both use feature qw( postderef ); and no warnings qw( experimental::postderef );, or by adding use experimental qw( postderef );.

Replies are listed 'Best First'.
Re^4: accessing stashes
by ikegami (Pope) on Mar 01, 2019 at 19:52 UTC

    Something changed in 5.22. $My::{$symbol} can return a code reference or -1 instead of a glob.

    The following is therefore needed:

    sub get_code_ref_by_fqn { # Fully qualified name my ($fqn) = @_; my @pkg_name_parts = split /::/, $fqn; my $symbol = pop(@pkg_name_parts); my $pkg = \%::; for (@pkg_name_parts) { $pkg = $pkg->{$_.'::'} or return undef; } my $glob_or_code = $pkg->{$symbol} or return undef; return $glob_or_code if ref($glob_or_code); return undef if ref(\$glob_or_code) ne 'GLOB'; return *$glob_or_code{CODE}; }

    But you know what, let's just leave those dirty details to Perl.

    sub get_code_ref_by_fqn { # Fully qualified name my ($fqn) = @_; no strict qw( refs ); return undef if !defined(&$fqn); return \&$fqn; }

    Above tested using

    use 5.012; use warnings; sub Foo::Bar::y; sub Foo::Bar::z { } say get_code_ref_by_fqn('Foo::Bar::x') // '[undef]'; say get_code_ref_by_fqn('Foo::Bar::y') // '[undef]'; say get_code_ref_by_fqn('Foo::Bar::z') // '[undef]';
Re^4: accessing stashes
by morgon (Priest) on Mar 01, 2019 at 19:25 UTC
    This is *exactly* what I was looking for - would you be so kind to rewrite my script above with your syntax (am interested in package "main") as I seem to be too drunk to do it myself and my attempts don't compile...

      Main is %:: (or %main:: (or %main::main:: (...))) instead of %My::.

        I know that.

        But I want one expression to determine the condition, I want to avoid (for reasons of pure idiocy) to have an extra assignment...

        So something like

        print defined *main::{$symbol}->*{CODE} ? "yep": "nope";
        But I cannot do it...

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