shift and splice don't work on lists.

These only work on arrays:

# Haskell programmer:
my ($head, @tail) = @array;

# Shell programmer
my $head = shift @array;
my @tail = @array;

# Perlfunc Author
my $head = splice @array, 0, 1;
my @tail = @array;
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These work on lists (including arrays):

# Haskell programmer:
my ($head, @tail) = list;

# Shell programmer
my @tail = list;
my $head = shift @tail;

# Perlfunc Author
my @tail = list;
my $head = splice @tail, 0, 1;
[download]

By the way, there's no need to put $head in list context for this splice.