Re: The best "true zero" is...

[mce]

Isn't 0E0 and "Larry's 0 but true" the same? :-)

[ambrus]

No, it's really the string "0 but true". Try this for example:

use File::Temp; $th = File::Temp::tempfile(undef, "UNLINK", 1); $zbt =
+ sysseek $th, 0, 0; print $zbt, "\n";

The "E0" suffix appears with the flip-flop operators, but "0E0" can never appear, only "1E0", "2E0" etc.

[mce]

true, but also not true :-)

Many functions -like the execute function in DBI- return 0E0 when they want to return a result that is ment to be zero but is 'boolean' true in tests

So, indeed it is not general perl, but it is common to use 0E0 as "zero but true".

Cheers,

[ambrus]

That's right, but the core perl uses only "0 but true", so "0E0" is not Larry's.

[tbone1]

Isn't 0E0 and "Larry's 0 but true" the same? :-)

Not at all. "0 but true" describes a state of data in Perl. "0E0" is part of the lyrics for the background singers in "Jungle Love" by Morris Day and the Time. Quite different.

[ikegami]

No.

$ perl -wle'print "0 but true" eq "0E0" ?1:0'
0

They are both silently equal to zero yet true, but so are the other poll options (except "0x0").

$ perl -wle'print 0+"0 but true"'
0

$ perl -wle'print 0+"0E0"'
0

$ perl -wle'print "0 but true" ?"true":"false"'
true

$ perl -wle'print "0E0" ?"true":"false"'
true