Project

General

Profile

Feature #12752

Updated by shyouhei (Shyouhei Urabe) over 3 years ago

When I parsed a binary protocol (msgpack) by `String#unpack`, there are many similar expressions, like below: 

 ```ruby 
 ``` 
 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 `.first`. 

 I'm happy if I can write the code above like this: 

 ```ruby 
 ``` 
 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) 
 # ... 
 ```

Back