perl -e 'my @scale=("A" .. "G"); my $note = -1; print (($note += 1) %= @scale)' #Working fine
0

perl -e 'my @scale=("A" .. "G"); print (0 %= @scale);' # Not working
Can't modify constant item in modulus (%) at -e line 1, near "@scale)"
Execution of -e aborted due to compilation errors.