in reply to Inlining a "lexically-scoped scalar which has no other references"

Neither a bug nor a doc error: 
# same as 'use constant FOO => 10'
BEGIN {
    my $lex = 10;
    *FOO = sub () { $lex };
}

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Dave.

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Re^2: Inlining a "lexically-scoped scalar which has no other references"
by BrowserUk (Patriarch) on Sep 28, 2009 at 04:57 UTC

    That's cool: 

    perl -MO=Deparse -e"BEGIN{ my $x = 12345; *Foo = sub(){ $x } }; print 
+Foo"
sub BEGIN {
    my $x = 12345;
    *Foo = sub () {
        $x;
    }
    ;
}
print 12345;
-e syntax OK

    [download]

    But why is the BEGIN block necessary?: 

    perl -MO=Deparse -e"{ my $x = 12345; *Foo = sub(){ $x }; } print Foo()
+"
{
    my $x = 12345;
    *Foo = sub () {
        $x;
    }
    ;
}
print Foo();
-e syntax OK

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    Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
    "Science is about questioning the status quo. Questioning authority".
    In the absence of evidence, opinion is indistinguishable from prejudice.
[reply]
[d/l]
[select]

      But why is the BEGIN block necessary?:

      You can't compile a subroutine call into a constant if the subroutine hasn't been made into a constant yet

[reply]

        So even though the sub declaration has been seen before you get to the call to it, it hasn't yet been compiled?

        Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
        "Science is about questioning the status quo. Questioning authority".
        In the absence of evidence, opinion is indistinguishable from prejudice.
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