From: Robert Klemme <shortcutter@...>
Date: 2009-08-20T19:57:06+09:00
Subject: Re: #has_arguments?

2009/8/19 Intransition <transfire@gmail.com>:
> Messing with optional argument check for the umpteenth time, eg.
>
>  def meth(a=Exception)
>    if a != Exception
>       ...
>    else
>      ...
>    end
>  end

My 0.02 EUR: if your method's behavior changes depending on argument
or argument types chances are that you may rather want different
methods.

As a side note: I see this sometimes

def m(a = nil)
  @a = a.nil? ? 123 : a
end

which is of course silly.  The same would be much better expressed as

def m(a = 123)
  @a = a
end

There is no need for additional optional logic - at least in these simple cases.

> Other's might do:
>
>  def meth(*a)
>    if !a.empty?
>      a = a.first
>       ...
>    else
>      ...
>    end
>  end
>
> Neither of which are very satisfying. So it occurs to me tonight that
> we already have #has_block? to see if a block was passed. So how about
> a #has_arguments? to query if _any_ arguments have been passed. So
> then...
>
>  def meth(a=default)
>    if has_arguments?
>       ...
>    else
>      ...
>    end
>  end
>
> Ah... now that would be nice.

It may be useful in some cases but since you can always do the "trick"
with "*" I am not sure whether we really need this.  I always found
block_given? a bit awkward since it looks like a method of self but is
rather a quick way to get at information about the argument list.  The
only reason I use it at times is the fact that the combination m(&b)
b.call is slower than the combination m() yield.

I'm undecided really.

Kind regards

robert

-- 
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