From: Guillaume Marcais <guslist@...>
Date: 2006-07-08T11:22:37+09:00
Subject: Re: Float#==. Legacy?

Le 7 juil. 06, � 15:30, Joel VanderWerf a �crit :

>
> The Float#=~ that Martin suggested is nice, but it still doesn't help 
> with one of the problems which (I think) the OP wanted:
>
> x = 1.2
> y = 1.2000000000000001
> p(x =~ y)       # => true
> p([x] =~ [y])   # => false
>

Yes, this is what I was referring to.

I came about a little differently. Mainly that calling 
Float#within_delta or equivalent is easy when I have the float itself, 
but if is embedded in an Array or Hash, it renders #== useless on the 
structure:

[1+1, 3] == [2, 3]        # => true
[0.1+0.2, 3] == [0.3, 3]  # => false

For the second case, one would needs to loop on the elements of the 
array.

And my second realization is if Float#== is (almost) always a mistake, 
why not change it to something useful most of the time. Changing 
Float#== in my code the way I did make me a little nervous as it is 
changing a pretty fundamental behavior, but on the other hand it is 
hardly ever used and it made sense in my case.

Guillaume.