Re^2: What I Most Recently Learned in Perl, But Should Have Already Known

[Hue-Bond]

perl -MO=Deparse -e ' print "true" if 1'

If we do if 0 something even funnier happens:

$ /usr/bin/perl -MO=Deparse -e 'print "true" if 0'
'???';

But which is most amusing is the fact that the deparsed code generates a warning:

$ /usr/bin/perl -w -e 'print "true" if 0'
$ /usr/bin/perl -w -e '"???"'
Useless use of a constant in void context at -e line 1.

[pKai]

'???' actually is no real thing. It's more like Deparse saying, this should be optimized away.

E. g. every "Useless use of a constant in void context" also results in this.