Re^5: printing unitialized value of the 'do BLOCK'

by LanX (Saint)

on Dec 23, 2019 at 12:54 UTC ( [id://11110548]=note: print w/replies, xml )

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> Interestingly, only one of these lines gives a warning:

because the second one returns an empty list, which is a legal use of print.

C:\WINDOWS\system32>Perl -MData::Dump=pp -e "pp do{3 if ()} "
undef

C:\WINDOWS\system32>Perl -MData::Dump=pp -e "pp do{()} "
()
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Cheers Rolf
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Re^6: printing unitialized value of the 'do BLOCK' by rsFalse (Chaplain) on Dec 23, 2019 at 21:22 UTC
Thanks, now I understand the difference: in the first case '()' wanted in scalar context which was forced by 'if' (so it becomes an undefined value). Added: An 'if' forces scalar context as 'and' do, so it may be that these two are internally implemented the same.	[reply]

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