From: matz@... (Yukihiro Matsumoto)
Date: 2002-12-25T08:38:14+09:00
Subject: Re: rescue statement modifier behavior change in 1.8.0

Hi,

In message "rescue statement modifier behavior change in 1.8.0"
    on 02/12/25, "Tim Hunter" <cyclists@nc.rr.com> writes:

|So I'm spending my Christmas Eve trying out new versions of Ruby. What a
|Christmas present!
|
|The following program works without error in 1.6.8. With the
|1.8.0preview1, the rescue statement modifier doesn't catch the IndexError.
|The program terminates with the message:
|
|[tim:~]$ ruby foo.rb
|foo.rb:4:in `bar=': bar too big (IndexError)
|        from foo.rb:16
|
|Is this a deliberate change in behavior?

Yes.

|Here's the program:
|
|class Foo
|    def bar=(b)
|        if b > 10
|            raise IndexError, "bar too big"
|        end
|    end
|end
|
|foo = Foo.new
|begin
|    foo.bar = 11
|rescue
|    foo.bar=10
|end
|
|foo.bar = 11 rescue 10
|exit

  foo.bar = 11 rescue 10

line was parsed as

  (foo.bar = 11) rescue 10

or

  begin
    foo.bar = 11
  rescue
    10
  end

on 1.6.x.  On 1.8.0, it is parsed as

  foo.bar = (11 rescue 10)

Put extra parenthesises, if you want the old behavior.

							matz.