Unpacking a value from a binary requires additional '.first'
When I parsed a binary protocol (msgpack) by
String#unpack, there are many similar expressions, like below:
str = io.read(1) length = str.unpack('C').first case length when 4 data = io.read(4).unpack('N').first # ...
I know that
unpack returns "1 or more" values, but I think there are too many cases to return just one object.
Creating Array objects for return values requires additional cost to create Array object, and calling
I'm happy if I can write the code above like this:
str = io.read(1) length = str.unpack('C', 0) # index, or str.unpack('C', index: 0) case length when 4 data = io.read(4).unpack('N', 0) # ...
Updated by mame (Yusuke Endoh) about 4 years ago
There is more concise way:
length, = str.unpack('C')
You cannot use this in a method chain, though.
I actually understand your frustration, but I feel no difference between
str.unpack('C', 0) and
Yusuke Endoh firstname.lastname@example.org