Some methods take a block, and this pattern frequently appears for a block: {|x| x.foo} and people would like to write that in a more concise way. In order to do that they use a combination of: a symbol, the method Symbol#to_proc, implicit class casting, and & operator. If you put & in front of … Read more
Another important but subtle difference between procs created with lambda and procs created with Proc.new is how they handle the return statement: In a lambda-created proc, the return statement returns only from the proc itself In a Proc.new-created proc, the return statement is a little more surprising: it returns control not just from the proc, … Read more
Those are not really files on disk (as you mention) but they are also not files in memory – the names in /proc correspond to calls into the running kernel in the operating system, and the contents are generated on the fly. The system doesn’t know how large the files would be without generating them, … Read more