Perl 5 version 20.3 documentation
- unshift EXPR,LIST
Note the LIST is prepended whole, not one element at a time, so the prepended elements stay in the same order. Use
reverseto do the reverse.
Starting with Perl 5.14,
unshiftcan take a scalar EXPR, which must hold a reference to an unblessed array. The argument will be dereferenced automatically. This aspect of
unshiftis considered highly experimental. The exact behaviour may change in a future version of Perl.
To avoid confusing would-be users of your code who are running earlier versions of Perl with mysterious syntax errors, put this sort of thing at the top of your file to signal that your code will work only on Perls of a recent vintage:
- use 5.014; # so push/pop/etc work on scalars (experimental)