As Logan pointed out in a different thread:
% ruby increment.rb
-:13: Can’t change the value of self
self = self + 1
So, how WOULD I create an .increment operator? I get why I can’t put it
in class Fixnum (well, I think I know why); Fixnums are symbol-ish-ly
unalterable. 5.increment should fail, for sanity’s sake.
So I have to add .increment to class . . . hmm. I can’t add it to
variables; they’re just references. But I want my_var.increment to
change ‘my_var’ so that it references the next integer in line.
Strings have methods that alter strings in place, but a String object
is a composite object, made up of characters, and !-type methods alter
the characters of the string without altering the variable’s reference.
Numbers aren’t composite objects. Maybe it can’t be done? But people
are constantly amazing me with crazy magical Ruby tricks; it seems so
improbable that there isn’t a way to do this as well . . .
Somebody else pointed out I could just my_var += 1. Yes, but to me,
that implies that the “1” is deliberate, and at some other point I
might add 2 or 5 or something, whereas using “inc” or “++” or whatever
says “it really doesn’t matter if I’m counting by ones, tens, Roman
numerals, or letters. This variable is just stepping upwards.”
But the main reason I’m asking is not to slightly improve the esthetics
of a couple lines of code. I’m certain that I’m going to learn
something interesting from the answer to the question.