[LRUG] The advantage of immutability?

[Riccardo Tacconi]

Yes I can recommend Tom's post to understand how to build immutable data
structures in Ruby. The problem is that Ruby is mainly an imperative
programming language and you will have harder time to use it in a more
functional way then directly using languages like Haskell. With Rails you
will have even harder time because it is a framework design to change the
state of shared objects. But it is possible and hard to figure out in the
beginning because you are trying to use immutability in a place where
mutability is everywhere (and JC explained that very well).

You were talking about Java Strings, I would add that strings should be
immutable, and Ruby should not allow the usage of mutable strings. Mutable
strings do not give any advantage and introduce only problems.

On 10 September 2015 at 10:39, Tom Stuart <tom at codon.com> wrote:

> On 10 Sep 2015, at 10:34, Stephen Best <bestie at gmail.com> wrote:
> > In every example I've seen immutability has certainly required more
> effort, but I don't think this always correlates with more complexity.
>
> This reminds me (belatedly) of a bit I wrote last year, on implementing
> immutable trees:
> http://codon.com/notes-on-counting-tree-nodes#immutable-trees
>
> I wrote that in an attempt to demonstrate how immutability can be useful —
> in that particular case, by making a data structure correct by
> construction, rather than having to write extra code to deal with malformed
> trees and so on. So I think that’s a decent example of how “more effort”
> (to implement the operations without mutation) leads to “[less] complexity”
> (because the resulting code is ultimately simpler to work with).
>
> Cheers,
> -Tom
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-- 
Riccardo Tacconi

http://github.com/rtacconi
http://twitter.com/rtacconi
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