Re: Naming convention to identify functions with side effects

[Gary Scott <garylscott@sbcglobal.net>]

(see below) wrote:

> On 04/10/2008 13:30, in article
> d49286ef-faa1-4b1b-8e23-0ed80c015dd2@p10g2000prf.googlegroups.com, "Marco"
> <prenom_nomus@yahoo.com> wrote:
> 
> 
>>On Oct 3, 5:28 am, "Dmitry A. Kazakov" <mail...@dmitry-kazakov.de>
>>wrote:
>>
>>>Side-effects are bad in any subprograms, be them functions or procedures.
>>
>>  Technically "side-effects" are being used whenever you change an
>>internal state in a module, which is not always undesired.
> 
> 
> These are not "side-effects", they are just effects.
> The whole point of using computers is to cause changes of state.

Some consider non-pure to include 1) changes in state of some "global" 
(non-local) entity (especially volatile items that can have state 
changed externally such as an I/O device) and 2) uses an argument return 
value in addition to a function return.  All of those are 
"side-effects".  The idea is that functions are only for calculating the 
return value based upon argument inputs.

> 
> 
>>proper expression is "unrelated side-effects are bad" which violates
>>the Principle of Least Surprise.
> 
> 
> Quite so.


-- 

Gary Scott
mailto:garylscott@sbcglobal dot net

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