[swift-evolution] ed/ing, InPlace, Set/SetAlgebra naming resolution

Fri Feb 12 18:13:05 CST 2016

on Fri Feb 12 2016, Craig Cruden <swift-evolution at swift.org> wrote:

> An algorithm (as far as I know) is not inherently mutable.  

Of course not; anything you can do with mutation, you can also do with
recursion and an infinite amount of memory.  But people don't have an
infinite amount of memory so they end up thinking in terms of mutation.

> It is a process of apply a certain process (or a certain function)
> over and over again until you have a result.

This quickly maps into replacing the argument values with new ones for
each application.

> If you processed it in writing (the common form of computing at the
> time) - you would write line after line of the results until you could
> break it down no farther (GCD).
>
> Each step clearly documented, clearly written down (not erasing a value and inserting a new value).  
>
> Basically you are applying a function on smaller and smaller bits
> (recursion) and recursion is not a mutable concept.
>
> But I think that is more than enough digression :p

Quite.

>
>
>> On 2016-02-13, at 5:21:46, Dave Abrahams via swift-evolution
>> <swift-evolution at swift.org> wrote:
>> 
>> 
>> on Fri Feb 12 2016, Craig Cruden
>> <swift-evolution at swift.org
>> <mailto:swift-evolution at swift.org>>
>> wrote:
>> 
>>> Not to mention - mutating (in my limited and aged math knowledge) is
>>> NOT mathematical (computer simulations might use math in simulations
>>> which simulating something that mutates)
>>> 
>>> Mathematicians (typically) don’t mutate - they might be mutants….  but
>>> they don’t mutate their equations.
>>> 
>>> When was the last time you saw a mutating equation?  If equations
>>> mutate then it makes it much more difficult to prove correctness.
>>> 
>>> Probably why even OO programming languages don’t allow you to mutate
>>> an Integer or Decimal ….. bad things can happen.
>>> 
>>> Union and intersection have more in common with operations like + and
>>> - which also do not mutate the values.
>> 
>> Let's not go too far with this.  Euclid invented the GCD algorithm,
>> which was originally expressed iteratively and therefore can be seen to
>> be mutating variables.  The whole concept of “algorithm” was named after
>> an arabic mathematician.
>> 
>>> 
>>> :p
>>> 
>>>>> Reasoning:
>>>>> 
>>>>> * I think the -ing endings sound unnatural, stilted, and unmathematical. They make me wince.
>>>>> * I think you have the nature of the words mis-assigned. In my
>>>>> opinion in this rare case, union, intersection, and exclusiveOr act
>>>>> as verbs as they are mathematical set operations. For example,
>>>>> "what is the result of A union B?" is a reasonable thing to say to
>>>>> a math person or put on an exam question, etc.
>>> 
>>>> 
>>> 
>>>> On 2016-02-12, at 22:20:01, Thorsten Seitz via swift-evolution
>>>> <swift-evolution at swift.org> wrote:
>>>> 
>>>> I beg to disagree with your reasoning.
>>>> I think "union" is more commonly used as a noun and "intersection"
>>>> certainly is not a verb. Your example sounded weird for me (but
>>>> maybe that's because I'm not a native speaker) and I would rather
>>>> expect the question to be "What is the union of A and B?"
>>>> 
>>>> -Thorsten 
>>>> 
>>>> Am 11.02.2016 um 20:09 schrieb Erica Sadun via swift-evolution
>>>> <swift-evolution at swift.org
>>>> <mailto:swift-evolution at swift.org
>>>> <mailto:swift-evolution at swift.org>>>:
>>>> 
>>>>> My expectations is that the standard operators act upon a set, changing the set. 
>>>>> 
>>>>> set1.union(with: set2) tells set1 to perform the union. 
>>>>> set1.unioned(with: set2) creates a new instance where set1 has been unioned with set 2.
>>>>> 
>>>>> Naming: intersected, unioned, and exclusiveOred over intersecting,
>>>>> unioning, exclusiveOring.
>>>>> Mutating: union, intersection, exclusiveOr. 
>>>>> Non-Mutating, returning new value: unioned(with), intersected(with), exclusiveOred(with)
>>>>> 
>>>>> Reasoning:
>>>>> 
>>>>> * I think the -ing endings sound unnatural, stilted, and unmathematical. They make me wince.
>>>>> * I think you have the nature of the words mis-assigned. In my
>>>>> opinion in this rare case, union, intersection, and exclusiveOr act
>>>>> as verbs as they are mathematical set operations. For example,
>>>>> "what is the result of A union B?" is a reasonable thing to say to
>>>>> a math person or put on an exam question, etc.
>>>>> 
>>>>> Importantly, they produce significant side effects, and should be
>>>>> treated as verbs that operate upon the receiver, updating the
>>>>> receiver, establishing their use for mutating ops.
>>>>> 
>>>>> Dave wrote:
>>>>>>>> - use nouns for methods with no side effects (or only incidental ones,  like logging)
>>>>>>>> - use verbs for methods with significant side-effects
>>>>> 
>>>>> 
>>>>> -- E
>>>>> 
>>>>>> On Feb 11, 2016, at 9:52 AM, Dave Abrahams via swift-evolution
>>>>>> <swift-evolution at swift.org
>>>>>> <mailto:swift-evolution at swift.org>
>>>>>> <mailto:swift-evolution at swift.org
>>>>>> <mailto:swift-evolution at swift.org>>>
>>>>>> wrote:
>>>>>> 
>>>>>> 
>>>>>> Hi All,
>>>>>> 
>>>>>> The API guidelines working group took up the issue of the InPlace suffix
>>>>>> yesterday, and decided that it was not to be used anywhere in the
>>>>>> standard library.  We are planning to apply the changes shown here
>>>>>> <https://gist.github.com/dabrahams/d872556291a3cb797bd5
>>>>>> <https://gist.github.com/dabrahams/d872556291a3cb797bd5>
>>>>>> <https://gist.github.com/dabrahams/d872556291a3cb797bd5
>>>>>> <https://gist.github.com/dabrahams/d872556291a3cb797bd5>>> to
>>>>>> the
>>>>>> API of
>>>>>> SetAlgebra (and consequently Set) to make it conform to the guidelines
>>>>>> under development.
>>>>>> 
>>>>>> Comments welcome as usual,
>>>>>> 
>>>>>> -- 
>>>>>> -Dave
>>>>>> 
>>>>>> _______________________________________________
>>>>>> swift-evolution mailing list
>>>>>> swift-evolution at swift.org
>>>>>> <mailto:swift-evolution at swift.org>
>>>>>> <mailto:swift-evolution at swift.org
>>>>>> <mailto:swift-evolution at swift.org>>
>>>>>> https://lists.swift.org/mailman/listinfo/swift-evolution
>>>>>> <https://lists.swift.org/mailman/listinfo/swift-evolution>
>>>>>> <https://lists.swift.org/mailman/listinfo/swift-evolution
>>>>>> <https://lists.swift.org/mailman/listinfo/swift-evolution>>
>>>>> 
>>>>> _______________________________________________
>>>>> swift-evolution mailing list
>>>>> swift-evolution at swift.org
>>>>> <mailto:swift-evolution at swift.org>
>>>>> <mailto:swift-evolution at swift.org
>>>>> <mailto:swift-evolution at swift.org>>
>>>>> https://lists.swift.org/mailman/listinfo/swift-evolution
>>>>> <https://lists.swift.org/mailman/listinfo/swift-evolution>
>>>>> <https://lists.swift.org/mailman/listinfo/swift-evolution
>>>>> <https://lists.swift.org/mailman/listinfo/swift-evolution>>
>>>> _______________________________________________
>>>> swift-evolution mailing list
>>>> swift-evolution at swift.org
>>>> <mailto:swift-evolution at swift.org>
>>>> https://lists.swift.org/mailman/listinfo/swift-evolution
>>>> <https://lists.swift.org/mailman/listinfo/swift-evolution>
>>> 
>>> _______________________________________________
>>> swift-evolution mailing list
>>> swift-evolution at swift.org
>>> <mailto:swift-evolution at swift.org>
>>> https://lists.swift.org/mailman/listinfo/swift-evolution
>>> <https://lists.swift.org/mailman/listinfo/swift-evolution>
>> 
>> -- 
>> -Dave
>> 
>> _______________________________________________
>> swift-evolution mailing list
>> swift-evolution at swift.org
>> <mailto:swift-evolution at swift.org>
>> https://lists.swift.org/mailman/listinfo/swift-evolution
>> <https://lists.swift.org/mailman/listinfo/swift-evolution>
> _______________________________________________
> swift-evolution mailing list
> swift-evolution at swift.org
> https://lists.swift.org/mailman/listinfo/swift-evolution

-- 
-Dave