Re^3: HTML::LinkExtor weirdness (scoping closures nested named subs)


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Re^3: HTML::LinkExtor weirdness (scoping closures nested named subs)

by Anonymous Monk

on Nov 07, 2013 at 00:27 UTC ( [id://1061507]=note: print w/replies, xml )

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in reply to Re^2: HTML::LinkExtor weirdness (scoping closures nested named subs)
in thread HTML::LinkExtor weirdness

This is why you don't nest named subs, the closure becomes "static"

perl -E " sub f{ my %g; sub g{say \%g; } g(); say \%g; \%g } say f(),$/ for 1 .. 4;"

perl -E ' sub f{ my %g; sub g{say \%g; } g(); say \%g; \%g } say f(),$/ for 1 .. 4; '


HASH(0xabd9c4)
HASH(0xabd9c4)
HASH(0xabd9c4)

HASH(0xabd9c4)
HASH(0x3f9b6c)
HASH(0x3f9b6c)

HASH(0xabd9c4)
HASH(0x3f9b8c)
HASH(0x3f9b8c)

HASH(0xabd9c4)
HASH(0x3f9b6c)
HASH(0x3f9b6c)

By making the nested subroutine a variable (also known as an anonymous sub), the closure is dynamic

$ perl -lE " sub f{ my %g; my $g = sub {say \%g; $g{1}++}; $g->(); say \%g; \%g } say f(),$/ for 1 .. 4;"


HASH(0xabd9d4)
HASH(0xabd9d4)
HASH(0xabd9d4)

HASH(0x3f9b1c)
HASH(0x3f9b1c)
HASH(0x3f9b1c)

HASH(0x99b374)
HASH(0x99b374)
HASH(0x99b374)

HASH(0x99b344)
HASH(0x99b344)
HASH(0x99b344)