From: Mark Thomas <mark@...>
Date: 2008-09-26T03:44:41+09:00
Subject: Re: Bug in the money gem?

On Sep 25, 2:32 pm, Eric LIn <ericlin...@gmail.com> wrote:
> For anyone of you using the money gem (http://dist.leetsoft.com/api/
> money/), I noticed today that 0 - 100 does not equal -100, it equals
> 100 instead (all numbers here represent Money objects).  Do any of you
> find that odd?

Yes, it's odd. The problem is line 80:

# File lib/money/money.rb, line 79
79:   def -(other_money)
80:     return other_money.dup if cents.zero?
81:     return dup if other_money.cents.zero?
82:
83:     if self.cents == 0 or currency == other_money.currency
84:       Money.new(cents - other_money.cents, other_money.currency)
85:     else
86:       Money.new(cents - other_money.exchange_to(currency).cents,
currency)
87:     end
88:   end

Try commenting line 80 out. I don't see any reason why the class
wouldn't handle negative values, though I didn't look carefully.

-- Mark.