warn documentation unclear

esharris has asked for the wisdom of the Perl Monks concerning the following question:

Here is an excerpt on "warn".

If LIST is empty and $@ already contains a value (typically from a previous eval) that value is used after appending "\t...caught" to $@. This is useful for staying almost, but not entirely similar to die.

If $@ is empty then the string "Warning: Something's wrong" is used.

The following code ...

#!/usr/bin/perl -w
warn;
$@ = 'Huh?';

warn;
warn '';
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... gives the following output.

Warning: something's wrong at ./temp4.pl line 2.
Huh?    ...caught at ./temp4.pl line 5.
Huh?    ...caught       ...caught at ./temp4.pl line 6.
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I didn't expect the last line, because the LIST is NOT empty; it has an empty string. Is ('') considered an empty list or is the documentation unclear?

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Replies are listed 'Best First'.
Re: warn documentation unclear by diotalevi (Canon) on Dec 08, 2005 at 03:06 UTC
The documentation is wrong. The empty string is not like an empty list but warn is treating them alike.	[reply]
Re: warn documentation unclear by TedYoung (Deacon) on Dec 08, 2005 at 15:37 UTC
I learned something new today. Thank you. I didn't know that warn propagated $@. It looks like die does too! `# Currently, I do this on occasion: do $file; die $@ if $@; # This seems like a better and shorter choice: do $file; die if $@;` [download] Ted Young `($$<<$$=>$$<=>$$<=$$>>$$) always returns 1. :-)`	[reply] [d/l] [select]
Re: warn documentation unclear by TedYoung (Deacon) on Dec 08, 2005 at 15:37 UTC
I learned something new today. Thank you. I didn't know that warn propagated $@. It looks like die does too! `# Currently, I do this on occasion: do $file; die $@ if $@; # This seems like a better and shorter choice: do $file; die if $@;` [download] Ted Young `($$<<$$=>$$<=>$$<=$$>>$$) always returns 1. :-)`	[reply] [d/l] [select]