From: ES <ruby-ml@...>
Date: 2005-05-27T09:42:35+09:00
Subject: Re: A different perspective on Ruby.


Le 27/5/2005, "johng" <jgoalby@gmail.com> a �crit:
>|"It's 5.abs for absolute value, but Math.sqrt(5) for square root."
>|
>|Good point.  That bugs me too.  abs is a *function*, not logically a
>|method.
>
>> The definition of abs is not questionable; it returns self, negated
>> when self is negative, for all numeric value.  On the other hand,
>> natural sqrt() may return float or integer, or something else.  That's
>> the reason for sqrt() being a function in Math module.
>
>I may be missing something, but why does it matter what the return
>type is?
>
>What is wrong with always returning a float just like Math.sqrt does?
>
>-alternatively, although I prefer the first option-
>
>Why couldn't the implementation of sqrt "cast" the result to an
>instance
>of the current self's type? So, if you ask an integer to sqrt, you get
>an
>integer back?
>
>Like I said, maybe I am missing something, but it seems that
>sqrt is a verb applied to numbers.

Well, essentially this is all that is required:

irb(main):018:0> class Fixnum
irb(main):019:1>   def method_missing(sym, *args, &block)
irb(main):020:2>     return Math.send sym, self, *args, &block
irb(main):021:2>   end
irb(main):022:1> end
=> nil
irb(main):023:0> 100.sqrt
=> 10.0
irb(main):024:0>

It is obviously not very robust but it took about eight seconds
to implement.

>John.

E

--
template<typename duck>
void quack(duck& d) { d.quack(); }