With Ruby, where to use NOT, AND, OR, XOR operations for Fixnum or Bignum?

Question

Hi,

Just wondering if anyone has any realworld examples or know when you might use the NOT, AND, OR, XOR, <<, >> operators in Ruby.

I've been programming for 4 years and never come across the need to use any of these, wondering how common actual usage is & if its something I should fully understand.

Thanks, -J

Answer 1

xor (aka ^), <<, and >> are more often used in lower-level programming. A C programmer will be intimately familiar with what these do. I'm writing an emulator in Ruby currently and use << and >> often in the 6502 core due to things like it having a 1 byte word size but 2 byte pc. You need to do bit shifting to save the pc onto the stack, for example.

not, and, and or are variations of !, &&, and ||, respectively. They work the same, but have a 'looser binding' to the variables around them. Their use (at least in practice) is to allow writing of expressions with fewer parens. I believe Rails actually forbids the use of these operators completely within its own codebase due to misunderstandings about how they work.

Answer 2

In an answer to another question, I was forced to do some bit-twiddling to work around a missing feature in the String#unpack / Array#pack pair of APIs. It uses left-shift (<<) and bitwise-or (|).