From: Michael Neumann <mneumann@...>
Date: 2004-11-17T23:50:00+09:00
Subject: Re: assert

Michael Neumann wrote:

> How about this:
> 
>   def breakpoint
>     file, line_no = caller.first.split(':', 2)
>     reason = File.readlines(file)[line_no.to_i - 1].
>       strip.sub(/^breakpoint\s+/, '')
>     p reason
>     # setup irb session etc.
>   end
> 
>   a = 4
>   breakpoint unless a == 5
> 
> This extracts the "unless a == 5" out of the source file. Of course, 
> that does not work for evaled-code (unless the source-buffer is stored 
> somewhere and we could access it).

This brings me to an idea I've seen in Python test-cases. They use 
docstrings before their "asserts", and these docstrings are then use 
when the assertion fails. Could we do this as well with comments?

(bad example):

Python:

   """Should be > 5"""
   assert(i > 5)

Ruby:

   # Should be > 5
   assert i > 5

This could avoid the use of the message parameter to the assert_* 
methods, which are used very seldom IMO. One disadvantage of comments is 
of course, that you can't use #{ ... }.

Regards,

   Michael