in reply to Re: methods for dealing with zero '0' as a string or char
in thread methods for dealing with zero '0' as a string or char

Just as an adjunct to what you have there, length returns FALSE for a zero-length EXPR and also an undefined EXPR. The latter behaviour was introduced in 5.12.0 (perl5120delta: Other potentially incompatible changes).

Interestingly, given the general discussion here, the FALSE value returned for a zero-length EXPR is 0, while the FALSE value returned for an undefined EXPR is undef.

— Ken

Replies are listed 'Best First'.
Re^3: methods for dealing with zero '0' as a string or char
by LanX (Saint) on Aug 16, 2019 at 13:08 UTC
    for clarification

    > Interestingly, given the general discussion here, the FALSE value returned for a zero-length EXPR is 0, while the FALSE value returned for an undefined EXPR is undef.

    Some operators in Perl return an internal magic boolean value, which is !!0 for FALSE and !!1 for TRUE.

    length is not one of them, it returns values which are interpreted as FALSE or TRUE, returning undef for undef is very consistent in my eyes.

    Though one probably could argue that warnings uninitialized should trow a warning here, I'm a bit confused in this matter.

    I remember that tobyink started a discussion once that warnings uninitialized leads to inconsistent behaviour.

    Cheers Rolf
    (addicted to the Perl Programming Language :)
    Wikisyntax for the Monastery FootballPerl is like chess, only without the dice

[reply]
[d/l]
[select]

In Section Seekers of Perl Wisdom