From ivan at llaisdy.com  Tue Oct 20 15:19:05 2015
From: ivan at llaisdy.com (Ivan Uemlianin)
Date: Tue, 20 Oct 2015 14:19:05 +0100
Subject: [99s-extend] Cowboy: Maps instead of records for context variables
Message-ID: <56263F49.2000206@llaisdy.com>

Dear All

Would there be any reason against using a map instead of a record for 
the context variable in a Cowboy REST resource?

Quite often I have a few resources doing very similar things in their 
callbacks, and I'd like to abstract out the similarities into a module - 
but I don't want to share a record between modules.

Maps seem to be a good fit, and I can't think of any downside 
(performance hit should be tiny).

Can anyone give me reasons to stick with records?

With thanks and best wishes

Ivan


-- 
============================================================
Ivan A. Uemlianin PhD
Llaisdy
Speech Technology Research and Development

                     ivan at llaisdy.com
                         @llaisdy
                          llaisdy.wordpress.com
               github.com/llaisdy
                      www.linkedin.com/in/ivanuemlianin

                         festina lente
============================================================


From essen at ninenines.eu  Tue Oct 20 15:22:39 2015
From: essen at ninenines.eu (=?UTF-8?Q?Lo=c3=afc_Hoguin?=)
Date: Tue, 20 Oct 2015 15:22:39 +0200
Subject: [99s-extend] Cowboy: Maps instead of records for context
 variables
In-Reply-To: <56263F49.2000206@llaisdy.com>
References: <56263F49.2000206@llaisdy.com>
Message-ID: <5626401F.9050907@ninenines.eu>

On 10/20/2015 03:19 PM, Ivan Uemlianin wrote:
> Dear All
>
> Would there be any reason against using a map instead of a record for
> the context variable in a Cowboy REST resource?
>
> Quite often I have a few resources doing very similar things in their
> callbacks, and I'd like to abstract out the similarities into a module -
> but I don't want to share a record between modules.
>
> Maps seem to be a good fit, and I can't think of any downside
> (performance hit should be tiny).
>
> Can anyone give me reasons to stick with records?

The only reason to use records is to keep typespecs information to 
improve Dialyzer's error reporting.

Personally I have no problems going with just maps for all kinds of 
states, even if they are in the same module. This is partly because I 
rely a lot more on tests than on Dialyzer to tell me my program is wrong.

Cheers,

-- 
Lo?c Hoguin
http://ninenines.eu
Author of The Erlanger Playbook,
A book about software development using Erlang