From: Adam Prescott <adam@...>
Date: 2012-01-22T11:24:45+09:00
Subject: Re: Microrant on Ruy's Math Skills

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On Sun, Jan 22, 2012 at 02:08, Intransition <transfire@gmail.com> wrote:

> Yea, I just don't expect Ruby's first priority to be speed. I tend to
> expect POLS, which I would think would lead to giving priority to precision
> (which I suppose means BigDecimal) but allow the option for faster floating
> point if needed.
>

Since you mentioned POLS, the standard thing to remember is that it's
Matz's surprise, once you understand Matz's view of things. :) Aside from
that, though, if you understand that 0.9 is a floating point number, and
you're coming from other languages where this is the case, then you
understand what it means to compare 0.9 to another number which displays as
0.9.

"%.60f" % 0.9
#=> "0.900000000000000022204460492503130808472633361816406250000000"

But I also recognise that it will throw people completely new to
programming who have no appreciation for what's happening beneath various
levels of abstraction created by the language when the issue arises.

Also, this is probably obligatory:
http://docs.oracle.com/cd/E19957-01/806-3568/ncg_goldberg.html (I'm
surprised it hasn't been mentioned yet!)

(For the POLS thing in Ruby:
https://en.wikipedia.org/wiki/Ruby_(programming_language)#Philosophy )

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