in reply to Re: How does 'goto LABEL' search for its label? (call stack)
in thread How does 'goto LABEL' search for its label?
> As for there being a new warning for if(1){X:...} goto X:, I lack the details for why this got deprecated.
It's analogous to if(0) the constant block is optimized to a do-block¹ ...
> perl -MO=Deparse -E'if (1) { label: say 1;}; goto label' BEGIN { $^H{'feature_say'} = q(1); $^H{'feature_state'} = q(1); $^H{'feature_switch'} = q(1); } do { label: say 1 }; goto label;
... which seems to fall into the same category like other loop-like-blocks:
ATM I have only 5.10 available. Could someone please test this with >= 5.12?
perl -wE'do { label: say 1;}; goto label'
EDIT: removed exit
Update
here test code w/o endless looping.
perl -wE'my $x=0;do { label: say $x++; die if $x>1}; goto label' 0 1 Died at -e line 1.
Update
Thanks to davido for testing
[davido]: LanX: perl -E 'goto IN; do{ IN: say "Hello world\n";};' does + produce the warning on 5.16.2.
Cheers Rolf
¹) which is somehow strange, I expected a simple bare block.
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