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From: "Alejandro R. Mosteo" <alejandro@mosteo.com>
Newsgroups: comp.lang.ada
Subject: Re: Community Input for the Maintenance and Revision of the Ada
 Programming Language
Date: Tue, 29 Aug 2017 18:01:02 +0200
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Xref: news.eternal-september.org comp.lang.ada:47833
Date: 2017-08-29T18:01:02+02:00
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On 11/08/17 08:24, G.B. wrote:
> On 11.08.17 03:31, Randy Brukardt wrote:
>> Speaking of evil, anonymous types are evil. Why is it hard to declare a
>> record type for this purpose?
> 
> A record is mutable, a tuple isn't meant to be mutable
> (i.e., can't update it's components). Also, it is harder
> to start from good types and names than to use a continous
> improvement process that finds them.
> 
> A tuple language will first let programmers write
> 
>     return Integer, Float,
> or
>     -> (Int, Float)
> or
>    int, float function;
> 
> and then let them use these values "generically": anything that
> takes an integer and a floating point value will work:
> argument pattern matching, or referring to Fst and
> Snd component using built-in ".0" and ".1" suffix notation.
> It then does not matter whether the integers and FPT values
> really are of types (apples, prices) or (oranges, weight)...
> 
> It is convenient.

Having used it profusely in matlab, it is indeed convenient, specially 
paired with things like "~" (ignore one of the returned values). But:

> It is prone to logical errors, because it'll make lazy
> programmers stop making good use of the type system, i.e.
> it eases accidentally mistaking apples for oranges,
> or price for weight, IOW make reasonably errors.

This.

Alex.

> 
> It is, therefore, a very viable scheme of language based
> supportbusiness.
> 
> 
> 
> OTOH, if (int, float) tuples used in the implementation
> of an ADT only, then the convenience might loose some of
> the disadvantages of depending on tuples.
>