From: Ross Bamford <rossrt@...>
Date: 2006-03-23T00:49:35+09:00
Subject: Re: questions/suggestions from a Ruby newbie

On Wed, 2006-03-22 at 23:38 +0900, Diego.Virasoro@gmail.com wrote:

> -Fortran 95 had a really nice feature when using arrays: you could
> assign values using ranges. I am glad to see something similar exist in
> Ruby too, (eg. variable[0..100]=0)
> However F95 went a bit further, since the ranges could include an
> optional parameter, the step. In F95 it would look something like:
> variable[min:max:step] = 0
> There's a lot of cases when something like this is really convinient. I
> know you can produce a similar effect using a few more lines, but I
> think a feature like a range+step would have several advantages, namely
> that it would look more clear in less code (a common feature in Ruby)
> and it's closer to the way we think to be very desirable. Has there
> been any talk about such a feature in future Ruby?
> 

I don't think this is doable with things as they are, since Ruby's
support for range indices differs from Fortran's (IIRC - I think
var[0:10:2] = 0 would set 0,2,4,6,8,10 ?).

In Ruby, when providing a range to Array#[]= it serves to select a
continuous range of elements that are to be replaced with a single
element (the RHS):

a = [:a, :b, :c, :d, :e, :f, :g, :h, :i, :j]
# => [:a, :b, :c, :d, :e, :f, :g, :h, :i, :j]

a[0..3] = 0
# => 0

a
# => [0, :e, :f, :g, :h, :i, :j]

> -What is the difference between the << and + concatenation for strings?
> Is it just that the former modifies the string while the second one
> returns a new string? Why then not use something like +!  (just as an
> alternative)?

I agree with David and Robert; when I first came over to Ruby I saw
plenty of stuff that could be 'made better', but now I'm used to it I
wouldn't change much at all. << is pretty consistently used throughout
Ruby and makes lots of stuff easy thanks to duck typing (string? array?
file? something else? who cares... :)) 

> Thank you very much. Anyway Ruby keeps being a great language and I
> really love it (though I have not use it much yet).

Give it a couple of months and you'll be using it for everything from
shuffling your music to documenting C code :)

-- 
Ross Bamford - rosco@roscopeco.REMOVE.co.uk