From: Brian Candler <B.Candler@...>
Date: 2007-04-14T04:01:50+09:00
Subject: Re: conditional statements within test method parameters?

On Sat, Apr 14, 2007 at 12:20:06AM +0900, Reuben Grinberg wrote:
> >I have a test method that writes some xml. The second parameter is
> >optional, the first parameter is boolean.
> >
> ><snip>
> >test_results((assert(REMEMBER_ME.isSet?)), *msg)
> ></snip>
> >
> >Would it be possible to embed a conditional statement between these
> >parameters
> >
> >Something like:
> >
> ><snip>
> >test_results((assert(REMEMBER_ME.isSet?)), unless 'the object is not
> >set') ?
> ></snip>
> >
> >cheers
> >
> >aidy
> >
> 
> Yes, but it's not necessarily pretty:
> 
> def test(one, *two)
> 	puts one
> 	two.each { |t| puts t}
> end
> 
> irb> test("bob", "jack", "andy")
> bob
> jack
> andy
> irb> test("bob")
> bob
> irb> some_condition = false
> irb> test("bob", some_condition ? ["jack", "andy"] : [])
> bob
> irb>
> 
> The "optional" argument is actually a list, so passing in the empty list 
> for it is the same thing as not passing it in.

I think you missed a '*' on the method call there.

As you've written it, in each case you're passing exactly two arguments, the
second of which is either ["jack","andy"] or [], so the array 'two' will
consist of either [["jack","andy"]] or [[]]

def test(one, *two)
  puts one.inspect, two.inspect
  puts
end

test("bob","jack","andy")
test("bob")
[false,true].each do |some_condition|
  test("bob", some_condition ? ["jack", "andy"] : [])
end
# This is what it should have been
[false,true].each do |some_condition|
  test("bob", *(some_condition ? ["jack", "andy"] : []))
end