Others have pointed out what is wrong with your code. Some have suggested interpolating the array, which I think is a good strategy here.

However, I haven't seen ?: in this thread yet. Which is strange, as all this if/elsif/... thing seems to do is assign to $from.

my $from =
    "@movement" eq '0 1'  ? 'north' :
    "@movement" eq '1 0'  ? 'east'  :
    "@movement" eq '0 -1' ? 'south' :
    "@movement" eq '-1 0' ? 'west'  :
    die "Unknown direction: (@movement)";
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I probably wouldn't use a lookup hash here. Redundancy's not so bad with only 4 items.