They do this instead: $hash{red}{green}{brown} = { }
True, that's what comes out of the for loop. Then the next instruction in my sample turns it into the requested result.. Is the following more to your liking? 
my $ptr = \%hash;
$ptr = $ptr->{$_} = {} for @array[0..$#array-1]; # fixed; s/shift @arr
+ay/$_/
$ptr->{$array[-1]} = 1;

[download]
or maybe 
my $ptr = \%hash;
$ptr = $ptr->{shift @array} = {} while @array > 1;
$ptr->{$array[0]} = 1;

[download]
Update: forgot to remove the shift when I initially copypasted. See comment.

Makeshifts last the longest.

In reply to Re^3: setting hash keys by array by Aristotle
in thread setting hash keys by array by hotshot

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