From: Michael Neumann <mneumann@...>
Date: 2004-06-05T18:37:43+09:00
Subject: Re: Check assertion in Ruby

On Sat, Jun 05, 2004 at 08:50:22AM +0900, David A. Black wrote:
> Hi --
> 
> On Sat, 5 Jun 2004, Michael Neumann wrote:
> 
> > On Sat, Jun 05, 2004 at 03:34:47AM +0900, Edgardo Hames wrote:
> > > Hi, everybody. I would like to use an assert like function to test the 
> > > number of rows returned by a query. Something like Eiffel's
> > > 
> > > check result.num_rows = 1
> > >
> > > What's the best way to do that in Ruby?
> > 
> >   def check
> >     raise "check failed" unless yield
> >   end
> > 
> > 
> >   check { result.num_rows == 1 }
> 
> I guess you could even do:
> 
>   def check(a)
>     raise "check failed" unless a
>   end

Or even better combining both approaches:

   def check(a=nil, &block)
     raise "check failed" unless (block ? block.call : a)
   end

Wouldn't that make sense to add to module Kernel? Or maybe named as
assert? 

I quite often need an assert method...

Regards,

  Michael