in reply to Re^5: Reference assessment techniques and how they fail (run?)
in thread Reference assessment techniques and how they fail
Here's a test for side effects of an eval test on a tied array.
use warnings; use strict; package ArrayTellTale; use base 'Tie::Array'; @ArrayTellTale::calls = (); sub TIEARRAY { bless [], __PACKAGE__ } sub FETCH { push @ArrayTellTale::calls, 'FETCH'; return $_[0]->[$_[1]]; } sub STORE { push @ArrayTellTale::calls, 'STORE'; $_[0]->[$_[1]] = $_[2]; } sub FETCHSIZE { push @ArrayTellTale::calls, 'FETCHSIZE'; return scalar @{$_[0]}; } sub STORESIZE { push @ArrayTellTale::calls, 'STORESIZE'; } package main; use Test::More 'tests' => 6; is_deeply( [ @ArrayTellTale::calls ], [], 'call log empty before tie' ); tie my @arr, 'ArrayTellTale'; is_deeply( [ @ArrayTellTale::calls ], [], 'call log empty after tie' ); @arr = ( 1, 2, 3 ); is_deeply( [ @ArrayTellTale::calls ], [ 'STORESIZE', 'STORE', 'STORE', 'STORE' ], 'call log after assignment' ); @ArrayTellTale::calls = (); my $ref_to_tied = \@arr; is_deeply( [ @ArrayTellTale::calls ], [], 'call log empty before eval test' ); my $is_array = eval { @{$ref_to_tied}; 1 }; is_deeply( [ @ArrayTellTale::calls ], [], 'call log empty after eval test' ); ok( $is_array, 'tied array ref detected as array' );
It seems the reason nothing is called during the test is that it's happening in void context. If I give the array dereference a context in the eval, it has to make a call to the object.
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