my @letter_seq = map(
		 $curr->[STYLE].":".join(',', splice @letter, 0, length($_)),
		 join('', @property{@letter}) =~ /\G(X|D+|L+)/g
);

# Join the result of a hash slice taken from the letter-to-property 
# mapping. Perform a match against the joined string to group together
# alphanumeric characters and leave all others distinct. Remove each match
# from the @letter array and join the character(s) to an output string such
# that the resulting format is i.e., "some_type:f4,!".